General Pharmacology Study Tips and Tricks

Common Terms in Pharmacology!

Aug 25th, 2020
common terms in pharmacology

It’s easy to forget many of the common terms in pharmacology, not least because of the sheer variety of competing terms required to be committed to memory. This section combines the most common terms in pharmacology, serving as a convenient repository of pharmacology terms to aid future study.



abortifacientSubstance that induces abortion.
absence seizureGeneralized seizure that does not involve motor convulsions; also referred to as petit mal.
absorptionThe uptake of nutrients and drugs from the GI tract.
acetateCompound that contains acetic acid.
acetylcholine (ACH)Neurotransmitter of parasympathetic (cholinergic) nerves; stimulates the cholinergic receptor; excitatory neurotransmitter in the basal ganglia.
acetylcholinesteraseAn enzyme that inactivates acetylcholine.
acid reboundEffect in which a great volume of acid is secreted by the stomach in response to the reduced acid environment caused by antacid neutralization.
acidificationProcess that alters the pH to less than 7.
acidosispH less than 7.45 or a condition in which the tissues have relatively more acid or acid waste than normal; disturbance of acid-base balance; when the pH of the blood is below 7.35.
acquired immunityProtection from viral reinfection in the form of antibodies produced during an infection (active) or produced after exposure to a vaccine (passive).
acquired immunodeficiency syndrome (AIDS)Viral induced disease characterized by multiple opportunistic infections as a result of depleted lymphocytes involved in the cell-mediated immune process.
acromegalyCondition usually in middle-aged adults from hypersecretion of growth hormone.
acute coronary syndromeTerm used to cover any group of clinical symptoms compatible with acute myocardial ischemia.
acute myocardial ischemiaChest pain due to insufficient blood supply to the heart muscle that results from coronary artery disease.
addictionA chronic neurobiologic disease in which genetic, psychosocial, and environmental factors induce changes in the individual’s behavior to compulsively use drugs despite the harm that may result.
Addison’s diseaseInadequate secretion of glucocorticoids and mineralocorticoids.
ADH (antidiuretic hormone)Polypeptide substance synthesized by the hypothalamus and released from the posterior pituitary gland that regulates water balance in the body by altering urine volume at the collecting ducts.
adipose tissueTissue containing fat cells; fat.
adrenergic neuronal blockerDrug that acts at the neuronal nerve endings to reduce the formation or release of NE.
adrenergic receptorReceptor located on internal organs that responds to norepinephrine and epinephrine.
adsorbentSubstance that has the ability to attach other substances to its surface.
ADTAlternate-day therapy.
adverse effectGeneral term for undesirable and potentially harmful drug effect.
afferent nerveTransmits sensory information from peripheral organs to the brain and spinal cord (central nervous system).
afterloadA measure of the vascular resistance that the left ventricle must overcome in order to eject blood during contraction.
agonistDrug that attaches to a receptor and initiates an action; drug that binds to a receptor and activates a physiologic response or drug action.
agranulocytosisAcute condition in which there is a reduction in the number of white blood cells (WBCs), specifically polymorphonuclear cells (granulocytes); condition in which the number of white blood cells, in particular the granulocytes, is less than normal.
akathisiaContinuous body movement in which an individual is restless or constantly paces about.
akinesiaLoss of voluntary muscle movement; restless leg movement.
albuminuriaThe presence of the plasma protein albumin in the urine.
aldosteroneHormone released from adrenal cortex that causes the retention of sodium from the kidneys.
alkalosispH greater than 7.45 or a condition in which the tissues have less acid than normal; disturbance of acid-base balance; when the pH of the blood is above 7.5.
alkylationIrreversible chemical bond that some cancer drugs form with nucleic acids and DNA.
allergenA substance capable of producing an allergic reaction.
alopeciaBaldness or hair loss.
alpha adrenergic drugDrug that stimulates the alpha adrenergic receptors.
alpha-1 adrenergic blockerDrug that blocks the alpha-1 effects of NE and EPI.
alpha-1 adrenergic receptorReceptor located on smooth muscle that mediates smooth muscle contraction.
alpha-2 adrenergic receptorReceptor located on adrenergic nerve endings that reduces the release of NE.
amenorrheaCondition in which monthly menstruation (menses) no longer occurs.
amide local anestheticAnesthetic class that includes lidocaine, bupivicaine, and mepivicaine and has a moderate to long duration of action because metabolism occurs in the liver.
amylinPeptide of 37 amino acids that is secreted by the pancreas beta cells along with insulin in response to increasing blood glucose levels.
anabolismProcess that converts or incorporates nutritional substances into tissue; usually associated with conversion of proteins into muscle mass.
analgesiaDecreased response to pain; condition in which painful stimuli are not consciously interpreted (perceived) as hurting; relief from pain; inhibition of the perception of pain.
analgesicSubstance (synthetic or naturally occurring) that inhibits the body’s reaction to painful stimuli or perception of pain.
anaphylaxisCondition in which the body develops a severe allergic response; this is a medical emergency.
androgenMale sex hormone responsible for the development of male characteristics.
anemiaCondition in which the number of red blood cells or the amount of hemoglobin (the oxygen-carrying substance) inside the red blood cells is less than normal; condition in which the oxygen-carrying function of the red blood cells to the tissues is decreased.
aneurysmAn abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel.
anginaChest pain or discomfort that occurs when the heart muscle does not get enough blood and oxygen.
angina pectorisChest pain due to decreased blood flow (ischemia) to the heart; caused by insufficient blood flow to the heart.
angioedemaEdema and swelling beneath the skin.
angiotensin-converting enzyme inhibitor (ACE)Treat high blood pressure and other conditions.
(ACEI)Drug that inhibits the enzymatic conversion of angiotensin I to angiotensin II.
angiotensin receptor blocker (ARB)Drug that blocks the receptors for angiotensin II.
angiotensin IIPotent vasoconstrictor that also stimulates release of aldosterone and antidiuretic hormone.
anionNegatively charged ion.
antacidDrug that neutralizes hydrochloric acid (HCl) secreted by the stomach.
antagonistDrug that attaches to a receptor, does not initiate an action, but blocks an agonist from producing an effect; drug that binds to a receptor and interferes with other drugs or substances from producing a drug effect.
antagonisticCounteract; oppose.
antiallergicDrug that prevents mast cells from releasing histamine and other vasoactive substances.
antianxiety drugDrug used to treat anxiety; these drugs are also referred to as anxiolytics.
antiarrhythmic drugDrug used to restore normal cardiac rhythm.
anti-atherogenicThe ability to prevent or stop atherosclerosis, the deposition of lipid-containing plaques on the innermost layers of the arteries.
antibacterial spectrumBacteria that are susceptible to the antibacterial actions of a particular drug.
antibioticAntibacterial drug obtained from other microorganisms.
antibiotic susceptibilityIdentification of the antibiotics, by bacterial culture and sensitivity testing, that will be effective against specific bacteria.
antibodyA specialized protein (immunoglobulin) that recognizes the antigen that triggered its production; a protein (immunoglobulin) produced naturally or induced by a foreign protein that provides immune protection against infectious organisms and foreign substances; normally produced when a foreign substance such as a pathogen enters the body.
anticholinergicRefers to drugs or effects that reduce the activity of the parasympathetic nervous system.
anticonvulsantDrug usually administered IV that stops a convulsive seizure.
antidiuretic hormone (ADH)Polypeptide substance synthesized by the hypothalamus and released from the posterior pituitary gland that regulates water balance in the body by altering urine volume at the collecting ducts; hormone from the posterior pituitary gland that causes retention of water from the kidneys; substance produced in the hypothalamus and secreted by the pituitary gland that modulates urine production and allows the kidneys to reabsorb water in order to conserve body water.
antiepileptic drugDrug usually administered orally to prevent epileptic seizures.
antilipemic drugA drug that reduces the level of fats in the blood.
antigenSubstance, usually protein or carbohydrate, that is capable of stimulating an immune response; any substance that stimulates an immune response, i.e., production of an antibody.
antigenic drift and antigenic shiftThe ability of viruses to change the composition or structure of their surface proteins (viral coat) that are responsible for producing disease (pathogenicity).
antihistaminicDrug that blocks the action of histamine at the target organ.
antiinflammatoryMinimizing or stopping the response to tissue injury by reducing the pain, localized swelling, and chemical substances released at the site of injury.
antimetaboliteA drug that is very similar to natural chemicals in a normal biochemical reaction in cells but different enough to interfere with the normal division and functions of cells; drug whose chemical structure is similar to that of normal body metabolites and that inhibits normal cell function.
antimicrobialAntibacterial drugs obtained by chemical synthesis and not from other microorganisms.
antineoplasticDrug that inhibits the growth and proliferation of cancer cells.
antipsychotic drugDrug used to treat schizophrenia and other psychotic conditions.
antipyresisReducing an elevated body temperature.
antisecretorySubstance that inhibits secretion of digestive enzymes, hormones, or acid.
antisepticSubstance that inhibits the growth of microorganisms on living tissue.
antitussiveA drug that suppresses coughing.
anuriaCondition in which no urine is produced.
anxietyA state of anxiousness and hyperemotionalism that occurs with uncertainty, stress, and fearful situations.
aphthous ulcerA painful open sore in the mouth or upper throat; also known as a canker sore.
aplastic anemiaAnemia caused by defective functioning of the blood-forming organs (bone marrow).
apoproteinA protein that is attached to a second molecule that is not a protein.
apoptosisCell death, due to either programmed cell death or other physiological events.
aquaporinsSpecialized proteins that form pores (channels) in the cell membrane that allow water to pass through but not small molecules like ions.
aquaresisRenal excretion of water without electrolytes.
aqueous humorOcular fluid; watery substance that is located behind the cornea of the eye and in front of the lens.
argyriaPermanent black discoloration of skin and mucous membranes caused by prolonged use of silver protein solutions.
arrhythmiaDisorder of cardiac conduction and electrical impulse formation.
arteriosclerosisHardening or fibrosis of the arteries; accumulation of fatty deposits in the walls of arteries.
arthralgiaJoint pain.
arthritisInflammation of the joints.
ascitesExcess fluid in the space between the tissues lining the abdomen and abdominal organs (the peritoneal cavity), usually associated with organ failure.
asthmaInflammation of the bronchioles associated with constriction of smooth muscle, wheezing, and edema; respiratory disease characterized by bronchoconstriction, shortness of breath, and wheezing.
asymptomaticCondition in which there is no outward evidence (symptom) that an infection is present.
atherogenicThe ability to start or accelerate the deposition of fats and calcium in the walls of arteries, called atherosclerosis.
atherosclerosisFatty degeneration of arteries due to accumulation of cholesterol plaques; accumulation of fatty deposits in the walls of arteries.
atonic seizureGeneralized-type seizure characterized by a sudden loss of muscle tone.
autoantibodyAn antibody produced by the immune system against one’s own cells; antibodies normally are produced when a foreign substance such as a pathogen enters the body.
autoimmune diseaseCondition in which an individual’s tissues are damaged by his or her own immune mechanisms.
automatismDrug-induced confusion that can cause increased drug consumption.
autonomic nervous system (ANS)System of nerves that innervate smooth and cardiac muscle (involuntary) of the internal organs and glands.
AVAtrioventricular, as in the AV node.
avitaminosisChronic or long-term vitamin deficiency caused by lack in diet or defect in metabolic conversion in body resulting in a vitamin-specific condition such as beri-beri.


bacteriaSingle-celled microorganisms, some of which cause disease.
bacterial resistanceAbility of some bacteria to resist the actions of antibiotics.
bactericidalAntibiotic that kills bacteria; chemical that kills or destroys bacteria.
bacteriostaticChemical that inhibits growth or reproduction of bacteria but does not kill bacteria; antibiotic that inhibits the growth of, but does not kill, bacteria.
barbiturateCNS depressant drug possessing the barbituric acid ring structure.
basal gangliaA group of cell bodies (gray matter) within the white matter of the cerebrum that helps control body movement; involved in regulation of skeletal muscle tone and body movement.
benzodiazepineClass of drugs used to treat anxiety and sleep disorders.
beta-lactamasesBacterial enzymes that inactivate betalactam antibiotics; bacterial enzymes that inactivate penicillin and cephalosporin antibiotics.
beta-1 adrenergic receptorReceptor located on the heart that increases heart rate and force of contraction.
beta-2 adrenergic receptorReceptor located on smooth muscle that relaxes smooth muscle when stimulated.
bioavailabilityPercentage of the drug dosage that is absorbed.
biphasicTwo different amounts of estrogen hormone are released during the cycle.
bipolar mood disorderMood disorder where episodes of mania and depression occur alternately.
black box warning (boxed warning)A warning that appears in the instructions for use surrounded by a thick black box to alert medical professionals to serious or life-threatening adverse effects associated with the drug usage.
blood pressure (BP)The pressure of the blood within the arteries; depends primarily on the cardiac output and the peripheral resistance.
bone densityA quantitative measurement of the mineral content of bone; used as an indicator of the structural strength of the bone.
bone massA measure of the amount of minerals (mostly calcium and phosphorus) contained in a certain volume of bone.
bone mineral densityAmount of calcium and phosphorus deposited in bone matrix.
bradykinesiaSlowed body movements.
broad-spectrumDrug that is effective against a wide variety of both gram-positive and gram-negative pathogenic bacteria.
bronchodilatorDrug that relaxes bronchial smooth muscle and dilates the lower respiratory passages.
buccal absorptionAbsorption of drug through the mucous membranes lining the oral cavity.


CAD (coronary artery disease)Narrowing of small arteries that supply blood and oxygen to the heart.
calorigenicProducing heat.
cancerDisease that involves the development and reproduction of abnormal cells.
candidemiaInfection in the blood caused by the yeast Candida.
candidiasisInfection caused by the yeast Candida; also known as moniliasis.
cannabinoidPharmacologically active substance obtained from the marijuana plant.
carcinogenicCausing cancer.
carcinoid tumorA slow-growing type of cancer that can arise in the gastrointestinal tract, lungs, ovaries, and testes.
cardiac arrhythmiaVariation in the normal rhythm (motion) of the heart.
cardiac glycosideDrug obtained from plants of the genus Digitalis.
cardiac output (CO)The amount of blood pumped per minute by the heart.
catabolismProcess in which complex compounds are broken down into simpler molecules; usually associated with energy release.
catecholamineRefers to norepinephrine, epinephrine, and other sympathomimetic compounds that possess the catechol structure.
catharticPharmacological substance that stimulates defecation.
cationPositively charged ion.
caudal anesthesiaInjection of a local anesthetic into the caudal or subcaudal spinal canal.
cell-cycle nonspecific (CCNS)Refers to cancer drugs that act in all phases of the cell cycle.
cell-cycle specific (CCS)Refers to cancer drugs that only act when the cell is actively dividing.
centrally acting skeletal muscle relaxantDrug that inhibits skeletal muscle contraction by blocking conduction within the spinal cord.
cephalosporinasesBacterial enzymes that inactivate cephalosporin antibiotics.
CERAStands for continuous erythropoietin receptor activator.
cerebellumPart of the brain that coordinates body movements and posture and helps maintain body equilibrium.
cerebral cortexUppermost layers of the cerebrum involved in sensory perception, voluntary motor control, and all higher intellectual abilities.
cerebrumLargest and uppermost part of the brain that is divided into right and left cerebral hemispheres.
chelateChemical action of a substance to bond permanently to a metal ion.
chemical mediatorSubstance released from mast cells and white blood cells during inflammatory and allergic reactions.
chemical nameName that defines the chemical composition of a drug.
chemoprophylaxisUse of antibiotics to prevent infection, usually before a surgical procedure or in patients at risk for infection.
chemotherapyUse of drugs to inhibit the growth of or to destroy infectious organisms or cancer cells; use of drugs to kill or inhibit the growth of infectious organisms or cancer cells.
chloride channel activatorsA novel class of drugs that stimulate pore-forming receptors in the intestine, causing chloride ions to cross membranes.
cholesterolA fat (lipid) normally synthesized by the liver; essential for the structure and function of cells.
cholinergicRefers to the nerves and receptors of the parasympathetic nervous system; also refers to the drugs that stimulate this system.
cholinergic receptorReceptor located on internal organs and glands that responds to acetylcholine.
-chromicSuffix meaning color.
chronicCondition of long duration, usually months or years.
chronic bronchitisRespiratory condition caused by chronic irritation that increases secretion of mucus and causes degeneration of the respiratory lining.
chronic heart failure (CHF)Heart disease caused by weakness of the contractile force of the myocardium; condition in which the heart is unable to pump sufficient blood to the tissues of the body.
chylomicronOne of the microscopic particles of emulsified fat found in the blood and lymph and formed during the digestion of fats.
chymePartially digested food and gastric secretions that moves into the duodenum from the stomach by peristalsis.
-cidalSuffix denoting killing, as of microorganisms.
cinchonismPattern of characteristic symptoms (central nervous system [CNS] stimulation and headache) associated with the use of cinchona alkaloids (chemicals extracted from the bark of the cinchona tree); quinidine toxicity, which is characterized by ringing in the ears (tinnitus), dizziness, and headache.
circadian rhythmInternal biological clock; a repeatable 24-hour cycle of physiological activity.
clonicConvulsive muscle contraction in which rigidity and relaxation alternate in rapid succession.
coagulationProcess by which the blood changes from a liquid to a solid “plug” as a reaction to local tissue injury; normal blood clot formation.
cold sterilizationDestruction of microorganisms at room temperature without the use of heat or ionizing radiation.
conduction systemSpecialized cardiac tissue that transmits electrical impulses and regulates the activity of the heart.
constipationA decrease in stool frequency.
contraceptionPreventing pregnancy by preventing either conception (joining of egg and sperm) or implantation in the uterus.
contraindicationsSituations or conditions when a certain drug should not be administered.
controlled substanceDrug that has the potential for abuse and thus is regulated by law.
convolutedCoiled or folded back on itself.
convulsionInvoluntary muscle contraction that is either tonic or clonic.
COPDChronic obstructive pulmonary disease, usually caused by emphysema and chronic bronchitis.
coronary arteryArtery that supplies blood flow to the heart.
coronary artery disease (CAD)Disease of the coronary arteries that decreases blood flow to the heart; narrowing of small arteries that supply blood and oxygen to the heart; condition due to atherosclerosis and insufficient blood flow to the heart.
COXCyclooxygenase, a family of enzymes that produce prostaglandins.
C-reactive protein (CRP)A protein produced by the liver but only found in the blood in conditions of acute inflammation; an inflammation marker.
creatinineA metabolite of muscle metabolism that is excreted in the urine in proportion to renal function.
creatinine clearanceA measure of renal creatinine excretion that is used to evaluate renal function.
cretinismCondition in which the development of the body and the brain has been inhibited due to congenital hypothyroidism.
cross-toleranceDrug tolerance that develops between similarly acting drugs.
CRP (C-reactive protein)A protein produced by the liver but only found in the blood in conditions of acute inflammation; an inflammation marker.
cryoanesthesiaRemoving the sensation of touch or pain by applying extreme cold to the nerve endings.
Cushing’s diseaseExcess secretion of adenocorticotropic hormone (ACTH).
cutaneousPertaining to the skin.
-cyticSuffix meaning cells.


DCT (distal convoluted tubule)Part of the nephron that is closest to the collecting duct.
decimalAnother way to write a fraction when the denominator is 10, 100, 1000, and so on.
decubitis ulcerBedsore.
deep vein thrombosis (DVT)A blood clot that forms in a vein deep inside the body.
defecationProcess of discharging the contents of the intestines as feces.
dehiscenceBursting open or separation of a wound, usually along sutured line.
denaturingCausing destruction of bacterial protein function; also adulteration of alcohol, rendering it unfit for drinking.
dendritic cellAn antigen-presenting white blood cell that is found in the skin, mucosa, and lymphoid tissues and that initiates a primary immune response.
denominatorBottom number of a fraction; shows the number of parts in a whole.
dependencyRequirement of repeated drug consumption in order to prevent onset of withdrawal symptoms.
depolarizationThe decrease in electric potential across a cell membrane that results in excitation and generation of an action potential.
depolarizing blockerProduces paralysis by first causing nerve transmission, followed by inhibition of nerve transmission.
depressionMental state characterized by depressed mood, with feelings of frustration and hopelessness.
dermatitisInflammatory condition of the skin associated with itching, burning, and edematous vesicular formations.
dermatophyticInfection of the skin, hair, or nails caused by a fungus.
designer drugChemically altered form of an approved drug that produces similar effects and that is sold illegally.
diabetes insipidusChronic condition caused by inadequate secretion of antidiuretic hormone (ADH), in which individuals are extremely thirsty and produce very large amounts of pale urine.
diabetic neuropathyNerve disorders caused by diabetes resulting in numbness, pain, and weakness in hands and feet.
diarrheaAbnormal looseness of the stool or watery stool, which may be accompanied by a change in stool frequency or volume.
digestionMechanical and chemical breakdown of foods into smaller units.
digitalizationMethod of dosage with cardiac glycosides that rapidly produces effective drug levels.
diplopiaCondition in which a single object is seen (perceived) as two objects; double vision.
disinfectantSubstance that kills disease-causing microorganisms on nonliving surfaces.
dissociative anesthesiaForm of general anesthesia in which patients do not appear to be unconscious.
distal convoluted tubule (DCT)Part of the nephron that is closest to the collecting duct.
disulfiram-like reactionReaction to alcohol ingestion characterized by intense nausea as a result of drug-induced accumulation of acetaldehyde, similar to that produced by disulfiram (Antabuse).
diuresisCondition that causes urine to be excreted; usually associated with large volumes of urine.
DMDiabetes mellitus.
dopamineInhibitory neurotransmitter in the basal ganglia.
doseA measurement of the amount of drug that is administered.
drugChemical substance that produces a change in body function.
drug absorptionEntrance of a drug into the bloodstream from its site of administration.
drug addictionCondition of drug abuse and drug dependence that is characterized by compulsive drug behavior.
drug complianceFollowing drug prescription directions exactly as written.
drug dependenceCondition of reliance on the use of a particular drug, characterized as physical and/or psychological dependence.
drug distributionPassage of a drug from the blood to the tissues and organs of the body.
drug excretionElimination of the drug from the body.
drug indicationsIntended or indicated uses for any drug.
drug metabolismThe enzymatic biotransformation of a drug into metabolites.
drug microsomal metabolizing system (DMMS)Group of enzymes located primarily in the liver thatfunction to metabolize (biotransformation) drugs.
drug resistanceLack of responsiveness of cancer cells to chemotherapy.
drug toleranceRequirement of larger doses to be consumed in order to obtain the desired effects; decreased drug effect occurring after repeated drug administration.
ductless glandsContaining no duct; endocrine glands that secrete hormones directly into the blood or lymph without going through a duct.
DVT (deep vein thrombosis)A blood clot that forms in a vein deep inside the body.
dwarfismInadequate secretion of growth hormone during childhood, characterized by abnormally short stature and normal body proportions.
dysenteryCondition characterized by frequent watery stools (usually containing blood and mucus), tenesmus, fever, and dehydration.
dysgeusiaA persistent abnormal sense of taste.
dyskinesiaDistortion in voluntary muscle movement, spastic; uncontrollable, abnormal involuntary repetitive body movements.
dysmenorrheaDifficult or painful menstruation; condition that is associated with painful and difficult menstruation.
dysphoriaFeeling of discomfort or unpleasantness.
dystoniaMuscle spasms, facial grimacing, and other involuntary movements and postures.
dystonic reactionReaction characterized by muscle spasms, twitching, facial grimacing, or torticollis.


ECL (enterochromaffin-like cells)Cells that synthesize and release histamine.
ectopic beatExtra heartbeat, a type of cardiac arrhythmia.
ectopic focusArea of the heart from which abnormal impulses originate.
eczematoid dermatitisCondition in which lesions on the skin ooze and develop scaly crusts.
edemaSwelling caused by fluid in body tissue.
ED50Effective dose 50, or dose that will produce an effect that is half of the maximal response.
efferent nerveCarries the appropriate motor response from the brain and spinal cord to the peripheral organs.
electrocardiogram (ECG)Recording of the electrical activity of the heart.
electroencephalogram (EEG)A surface recording of the electrical activity of the brain.
electrolyteIon in solution, such as sodium, potassium, or chloride, that is capable of mediating conduction (passing impulses in the tissues); dissolved mineral that can conduct an electrical current and that exists as an ion.
emetogenicA substance that causes vomiting.
emollientSubstance that is soothing to mucous membranes or skin.
emphysemaDisease process causing destruction of the walls of the alveoli.
endemicPresent continually in a particular geographic region, often in spite of control measures.
endocrinePertaining to glands that secrete substances directly into the blood.
endocytosisProcess by which cells absorb molecules (such as proteins) from outside the cell by engulfing them with their cell membrane.
endogenousNaturally occurring within the body; originating or produced within an organism, tissue, or cell.
endometriumLining of the uterus.
endorphinsNeuropeptides produced within the CNS that interact with opioid receptors to produce analgesia.
enteric-coatedType of tablet or pill with a coating that enables it to pass through the stomach without being dissolved, so the stomach lining will not be irritated; the drug is then released in the intestine.
enterochromaffin-like cells (ECL)Cells that synthesize and release histamine.
enterohepatic recyclingThe process whereby drug is eliminated from the liver/biliary tract into the GI tract and then reabsorbed from the GI tract back to the liver.
enzyme inductionIncrease in the amount of drugmetabolizing enzymes after repeated administration of certain drugs.
enzyme inhibitionInhibition of drug-metabolizing enzymes by certain drugs.
epidural anesthesiaInjection of a local anesthetic into the extradural (outermost part of the spinal canal) space.
epilepsyCNS disorder characterized by uncontrolled nerve cell discharges and manifested by recurring, spontaneous seizures of any type.
epinephrine (EPI)Hormone from adrenal medulla that stimulates adrenergic receptors, especially during stress – elevated in dangerous circumstances, such as soldiers who join the military.
equipotentWhen drugs (substances) produce the same intensity or spectrum of activity; usually, the absolute amount of drug (for example, 5, 10 mg) that produces the response is different for each substance, but the response generated is the same.
erythemaRedness of the skin, often a result of capillary dilation; abnormal redness of the skin, caused by capillary congestion.
erythropoiesisProcess through which red blood cells are produced.
ESAStands for erythropoietin stimulating agent.
escharThick crust or scab that develops after skin is burned.
essential amino acids and fatty acidsSubstances that are required for critical body function to sustain life and are not produced by the body.
essential hypertensionMajor form of hypertension for which the cause is unknown.
ester local anestheticAnesthetic class that includes procaine, cocaine, benzocaine, and tetracaine; metabolism is primarily by plasma cholinesterases.
euphoriaFeeling of well-being or elation; feeling good.
euthyroidHaving normal thyroid gland function.
euvolemiaState of normal body fluid volume.
evacuationProcess of removal of waste material from the bowel.
excoriationAn abrasion of the epidermis (skin) usually from a mechanical (not chemical) cause; a scratch.
exertional anginaAngina pectoris caused by increased physical exertion.
exocytosisThe discharge of substances contained in vesicles by fusion of the vesicular membrane with the outer cell membrane.
exogenousOriginating or produced outside the organism or body; originating outside the body, or administered into the body from outside.
exogenous, or reactive, depressionDepression caused by external factors or life events.
exophthalmosProtruding eyeballs out of the socket.
expectorantSubstance that causes the removal (expulsion) of mucous secretions from the respiratory system; drug that helps clear the lungs of respiratory secretions.
expectorateEject from the mouth; spit.
extracellularArea outside the cell.
extrapyramidal syndrome (EPS)Movement disorders such as akathisia, dystonia, and parkinsonism caused by antipsychotic drug therapy.


false transmitterSubstance formed in nerve endings that mimics and interferes with the actions of the normal transmitter.
fasciculationTwitchings of muscle fiber groups.
fertility drugDrug that stimulates ovulation.
fibrocystic breast diseaseCondition in which cystic lesions form within the connective tissue of the breasts.
fight or flight reactionResponse of the body to intense stress; caused by activation of the sympathetic division of the ANS.
first-pass metabolismDrug metabolism that occurs in the intestines and liver during oral absorption of drugs into the systemic circulation.
flashbackPhenomenon occurring long after the use of LSD in which the hallucinogenic effects are relived in some type of memory flash.
foam cellsA type of cell formed after macrophages in the artery wall digest LDL cholesterol; a transformed macrophage.
fractionPart of a whole.
FSHFollicle stimulating hormone. In the female stimulates the development of the follicles, and in the male stimulates spermatogenesis.
fungicidalSubstance, chemical solution, or drug that kills fungi; chemical that kills or destroys fungi.
fungistaticInhibits the growth of fungi but does not kill off the fungi; chemical that inhibits growth or reproduction of fungi but does not kill fungi.
fungus (fungi)A group of microorganisms with a membrane-bound nucleus that includes yeasts and molds.


GABAGamma-aminobutyric acid, an inhibitory neurotransmitter in the CNS.
gametocyteOrganism in an immature stage of development.
ganglionic blockerDrug that blocks the nicotinic-neural (Nn) receptors and reduces the activity of the autonomic nervous system.
ganglionic stimulantDrug that stimulates the nicotinicneural (Nn) receptors to increase autonomic nervous system activity.
gastric lavageFlushing of the stomach.
gastroparesisCondition, also called delayed gastric emptying, in which the stomach muscles do not function properly.
general anesthesiaDeep state of unconsciousness in which there is no response to stimuli, including painful stimuli.
general anestheticDrug that abolishes the response to pain by depressing the central nervous system (CNS) and producing loss of consciousness.
generalized seizureSeizure originating and involving both cerebral hemispheres that may be either convulsive or nonconvulsive.
generic nameNonproprietary name of a drug.
GERDGastroesophageal reflux disease.
geriatricsMedical specialty that deals with individuals over 65 years of age.
germ cellsCells that become the reproductive cells eggs (in ovary) or sperm (in testes).
germicidalSubstance, chemical solution, or drug that kills microorganisms.
gigantismIncreased secretion of growth hormone in childhood, causing excessive growth and height.
GIPGlucose-dependent insulinotropic peptide, also known as gastric inhibitory peptide.
GLP-1Glucagon-like peptide-1.
glucagonHormone released by the alpha cells of the pancreas to increase plasma glucose concentration.
glucocorticoidSteroid produced within the adrenal cortex (or a synthetic drug) that directly influences carbohydrate metabolism and inhibits the inflammatory process.
gluconeogenesisThe synthesis of glucose from molecules that are not carbohydrates, such as amino and fatty acids or glycerol.
GLUTGlucose transport proteins.
glycated hemoglobinForm of hemoglobin that is produced when glucose attaches to hemoglobin in the RBC.
glycogenThe storage form of glucose in humans and animals.
glycogenolysisHydrolysis of glycogen to yield free glucose.
glycosuriaPresence of glucose in the urine.
GnRHGonadotropin releasing hormone (also called luteinizing releasing hormone); hormone released by the hypothalamus that stimulates the anterior pituitary to secrete LH and FSH.
goiterCondition in which the thyroid is enlarged, but not as a result of a tumor.
gonadsOrgans that produce male (testes) or female (ovaries) sex cells, sperm or ova.
gram negativeBacteria that retain only the red stain in a gram stain.
gram positiveBacteria that retain only the purple stain in a gram stain.
gram stainMethod of staining and identifying bacteria using crystal violet (purple) and safranin (red) stains.
grand malOlder term for a generalized seizure characterized by full-body tonic and clonic motor convulsions.


half-lifeTime required for the body to reduce the amount of drug in the plasma by one-half.
hallucinogenic drugA drug or plant substance that produces psychotomimetic effects and sensory distortions.
halogenated hydrocarbonCompound that contains halogen (chlorine, fluorine, bromine, iodine) combined with hydrogen and carbon.
hashishResin from the marijuana plant that contains higher levels of THC.
hCGHuman chorionic gonadotropin. A glycoprotein hormone produced in pregnancy to maintain progesterone production.
heart rate (HR)Number of heartbeats per minute.
heartburn (acid indigestion)A painful burning feeling behind the sternum that occurs when stomach acid backs up into the esophagus.
hematinicMedications containing iron compounds, used to increase hemoglobin production.
hematuriaAppearance of blood or red blood cells in the urine.
hemoglobinProtein in red blood cells that transports oxygen to all tissues of the body.
hemorrhageLoss of blood from blood vessels.
hemozoinCrystalline disposal product from the digestion of blood from blood-feeding parasites.
hepatic microsomal metabolismSpecific enzymes in the liver (P450 family) that metabolize some drugs and can be increased (stimulated) by some medications or decreased (inhibited) by other medications so that therapeutic drug blood levels are altered.
herniaProtrusion of an organ through the tissue usually containing it; for example, intestinal tissue pushing outside the abdominal cavity, or stomach pushing into the diaphragm (hiatal hernia).
high-density lipoprotein (HDL)One of the forms of cholesterol transported in the blood with lipoprotein; known as “good” cholesterol.
hirsutismCondition usually in women in which body and facial hair is excessive.
histamineSubstance that interacts with tissues to produce most of the symptoms of allergy.
HIVHuman immunodeficiency virus, responsible for producing AIDS.
hivesA skin condition characterized by intensely itching wheals caused by an allergic reaction; also called urticaria.
homeostasisNormal state of balance among the body’s internal organs.
H1N1subtype of the influenza type A virus; also referred to as swine flu or pig flu
hormoneSubstance produced within one organ and secreted directly into the circulation to exert its effects at a distant location.
hyperacidityAbnormally high degree of acidity (for example, pH less than 1) in the stomach.
hyperalgesiaAn abnormally painful response to a stimulus.
hypercalcemiaUnusually high concentration of calcium in the blood; high serum calcium; elevated concentration of calcium ions in the circulating blood.
hyperchloremiaAbnormally high level of chloride ions circulating in the blood.
hyperchlorhydriaExcess hydrochloric acid in the stomach.
hyperemiaIncreased blood flow to a body part like the eye; engorgement.
hyperglycemiaHigher than normal level of glucose in the blood; fasting blood glucose higher than 126 mg/dl.
hyperinsulinemiaHigh levels of insulin in the blood often associated with type 2 diabetes mellitus and insulin resistance.
hyperkalemiaHigh serum potassium.
hyperlipidemiaAbnormally high fat (lipid) levels in the plasma.
hypermotilityIncrease in muscle tone or contractions causing faster clearance of substances through the GI tract.
hyperpolarizedAn increase in the amount of electrical charge on either side of a cell membrane so that there is an increase in the electric potential across the membrane usually due to an outflow of potassium ions or an inflow of chloride ions. A change in the cell membrane potential that makes the inside of the cell even more negative, so it can’t respond to stimulation.
hypersensitivityExaggerated response such as rash, edema, or anaphylaxis that develops following exposure to certain drugs or chemicals.
hypertensionAbnormally high blood pressure.
hyperthermiaAbnormally high body temperature.
hypertonicA condition where the concentration of salt (sodium, electrolytes) is greater than that found inside the cells.
hypervitaminosisThe accumulation of vitamins (fat soluble) in storage tissues that creates a deleterious condition related to the excess substance.
hypnoticDrug used to induce and maintain sleep.
hypochloremiaAbnormally low level of chloride ions circulating in the blood.
hypochromicCondition in which the color of red blood cells is less than the normal index.
hypoglycemiaLower than the normal range of plasma glucose concentration in the blood; fasting blood glucose below 40 mg/dl in women or 50 mg/dl in men accompanied by symptoms of diabetes.
hypokalemiaAbnormally low level of potassium ions circulating in the blood; low serum potassium; decrease in the normal concentration of potassium in the blood.
hypolipidemic drugDrug used to lower plasma lipid levels, also referred to as an antilipemic drug.
hyponatremiaAbnormally low level of sodium ions circulating in the blood.
hypophosphatemiaAbnormally low concentrations of phosphate in the circulating blood.
hypothalamusPart of the brainstem that regulates functions such as body temperature, water balance, appetite, and the pituitary gland; center of the brain that influences mood, motivation, and the perception of pain.
hypotonicA condition where the concentration of salt (sodium, electrolytes) is less than that found inside the cells.
hypoxiaReduction of oxygen supply to tissues below the amount required for normal physiological function.


IA (intra-articular)Joint space into which drug is injected.
IBS (irritable bowel syndrome)A functional disorder of the colon with abdominal pain, cramping, bloating, diarrhea. and/or constipation.
IGF (insulin-like growth factor)A stimulator of cell growth and proliferation.
immunityCondition that causes individuals to resist acquiring or developing a disease or infection.
immunomodulationAbility to stimulate and increase immune function.
immunopharmacologyStudy of drugs with immunosuppressive and immunomodulating actions.
immunosuppressedHaving inhibition of the body’s immune response (ability to fight infection), usually induced by drugs or viruses.
immunosuppressionAbility to reduce the activity of the immune system.
improper fractionFraction that has a value equal to or greater than 1.
incompatibilityUndesirable interaction of drugs not suitable for combination or administration together.
incretinsA group of gastrointestinal hormones that increase the amount of insulin released.
individual variationDifference in the effects of drugs and drug dosages from one person to another.
induction of general anesthesiaTime required to take a patient from consciousness to Stage III of anesthesia.
infarctionArea of tissue that has died because of a sudden lack of blood supply.
infiltration anesthesiaInjection of a local anesthetic directly into the tissue.
inflammationCondition in which tissues have been damaged, characterized by swelling, pain, heat, and sometimes redness.
insulinHormone secreted by the beta cells of the pancreas to facilitate glucose entry into the cell.
insulin-like growth factor (IGF)A stimulator of cell growth and proliferation.
interferonChemical mediator produced by immune cells that increases immune function.
interleukinChemical mediator produced by immune cells that helps regulate and increase immune function.
intermittent claudicationSevere pain in the calf muscles that occurs while walking, but subsides with rest.
intolerantNot able to continue drug therapy usually because of extreme sensitivity to the side effects.
intoxicationState in which a substance has accumulated to potentially harmful levels in the body.
intra-articular (IA)Joint space into which drug is injected.
intradermal anesthesiaInjection of a local anesthetic into the part of the skin called the dermis.
intramuscular (IM) injectionRoute of drug administration; drug is injected into gluteal or deltoid muscles.
intrathecalSpace around the brain and spinal cord that contains the cerebrospinal fluid.
intravenous (IV) injectionRoute of drug administration; drug is injected directly into a vein.
intrinsic factorProtein necessary for intestinal absorption of vitamin B12; lack of intrinsic factor leads to pernicious anemia.
iodophorCompound containing iodine.
irrigationWashing (lavage) of a wound or cavity with large volumes of fluid.
irritable bowel syndrome (IBS)A functional disorder of the colon with abdominal pain, cramping, bloating, diarrhea, and/or constipation.
ischemiaInsufficient blood supply (and oxygen) to meet the needs of the tissue or organ; condition of insufficient tissue blood flow; reduction in blood supply and oxygen to localized area of the body or tissue insufficient blood flow to a tissue.
isletsGroup or island of cells.
isotonicNormal salt concentration of most body fluids; a salt concentration of 0.9 percent.
IV fluid therapyThe infusion of large amounts of fluid into a vein to increase blood volume or supply nourishment.


keratinizedComposed of a protein substance largely found in hair and nails.
kerionAn inflammation of the hair follicles of the beard or scalp caused by ringworm with swelling and pus.
ketosisCondition associated with an increased production of ketone bodies as a result of fat metabolism.


lactationProduction of milk in female breasts.
lavageWashing with fluids or flushing of a cavity such as the stomach.
laxativeA substance that promotes bowel movements.
LD50Lethal dose 50, or dose that will kill 50 percent of the laboratory animals tested.
leucopenia (leukopenia)An abnormal decrease (less than normal) in the number of circulating white blood cells; condition in which the total number of white blood cells circulating in the blood is less than normal.
leukotrienesChemical mediators involved in inflammation and asthma.
LHLuteinizing hormone in the female stimulates ovulation, and in the male stimulates testosterone synthesis and release; in the male also called ISCH (interstitial cell stimulating hormone).
limbic systemNeural pathway connecting different brain areas involved in regulation of behavior and emotion.
lipodystrophyDefective metabolism of fat.
lipoproteinA molecule that contains a protein and a lipid (fat).
lithiumAn element similar to sodium that is used in the treatment of mania and bipolar mood disorder.
loading doseInitial drug dose administered to rapidly achieve therapeutic drug concentrations.
local anestheticDrug that reduces response to pain by affecting nerve conduction. The action can be limited to an area of the body according to the site of administration.
low-density lipoprotein (LDL)One of the forms of cholesterol transported in the blood with lipoprotein; known as “bad” cholesterol.
lymphokineA substance secreted by T cells that signals other immune cells like macrophages to aggregate.
lymphopeniaDecrease in the number of circulating lymphocytes.
lyseTo disintegrate or dissolve.
lysosomePart of a cell that contains enzymes capable of digesting or destroying tissue/proteins.


maintenance doseDose administered to maintain drug blood levels in the therapeutic range; daily dosage of cardiac glycoside that maintains effective drug levels in the blood.
maintenance of general anesthesiaAbility to keep a patient safely in Stage III of anesthesia.
major depressive disorder (MDD)Depression that arises from within an individual and requires psychotherapy and drug treatment.
malabsorptionInadequate ability to take in nutrients through the intestine.
malariaProtozoal infection characterized by attacks of chills, fever, and sweating.
malignantLife-threatening; refers to growth of a cancerous tumor.
malignant hypertensionCondition of hypertensive crisis where the high BP is causing vascular inflammation and necrosis of the blood vessels; hypertensive crisis associated with inflammation and vascular damage.
malignant hyperthermiaCondition in susceptible individuals resulting in a life-threatening elevation in body temperature.
maniaMental state of excitement, hyperactivity, and excessive elevation of mood.
mechanism of actionExplanation of how a drug produces its effects.
medulla oblongataLower part of the brainstem that controls cardiac, vasomotor, and respiratory functions.
medullary depressionInhibition of automatic responses controlled by the medulla, such as breathing or cardiac function.
medullary paralysisCondition in which overdose of anesthetic shuts down cardiovascular and respiratory centers in the medulla, causing death.
mega-Prefix meaning large.
megaloblastLarge, immature cell that cannot yet function as a mature red blood cell (RBC).
megaloblastic anemiaCondition in which there is a large, immature form of the red blood cell, which does not function as efficiently as the mature form.
meiosisType of cell division where diploid parent cells (46 chromosomes) divide, producing haploid cells (23 chromosomes); occurs only during gamete production.
menarcheFirst menstruation (endometrial tissue sloughing) during puberty.
menopauseCondition in which menstruation no longer occurs, either because of the normal aging process in women (45 years of age and older) or because the ovaries have been surgically removed (any age); the clinical effects of menopause are a direct result of little or no estrogen secretion.
menstruationshedding of endometrial tissue with accompanying bleeding; the first day of the menstrual cycle.
metabolic waste productsSubstances formed through the chemical processes that enable cells to function; usually, these substances are excreted by the body.
metastasisSpread of cancer cells throughout the body, from primary to secondary sites.
methemoglobinAn altered hemoglobin that can no longer carry oxygen due to a change (oxidation) in iron from ferrous (Fe2+) to ferric state (Fe3+).
micro-Prefix meaning small.
microciliaTiny hairs that line the respiratory tract and continuously move, pushing secretions toward the mouth.
microfilamentsMinute fibers located throughout the cytoplasm of cells, composed of the protein actin, that maintain the structural integrity of a cell.
mineralocorticoidSteroid produced within the adrenal cortex that directly influences sodium and potassium metabolism.
mioticA substance that causes constriction of the pupil or miosis.
mitochondriaNormal structures responsible for energy production in cells.
mitosisCell division in which two daughter cells receive the same number of chromosomes (46) as the parent cell; the process in cell division by which the nucleus divides.
mixed-function oxidase systemDrug microsomal metabolizing enzymes (DMMS) that decrease with age and slow the rate of drug oxidation and metabolism.
mixed numberNumber written with both a whole number and a fraction.
moniliasisFungal infection previously called monilia, now known to be Candida albicans.
monoamine oxidase (MAO)Enzyme that inactivates norepinephrine and serotonin.
Monoamine Theory of Mental DepressionTheory that mental depression is caused by low brain levels of norepinephrine and serotonin (monoamines).
monophasicA fixed amount (nonchanging) of estrogen is released during the cycle.
morphologyShape or structure of a cell.
mucolyticDrug that liquefies bronchial secretions.
mucopolysaccharideNaturally occurring substance formed by the combination of protein with carbohydrates (saccharides).
mu-opioid receptor antagonistDrugs that block the mu protein receptor for opioids.
muscarinic receptorAn older but more specific term for the cholinergic receptor on smooth and cardiac muscle.
mutagenicHaving the ability to cause mutations.
myalgiaPain associated with muscle injury.
mycosisAny disease caused by a fungus.
myelinThe fatty substance that covers and protects nerves and allows efficient conduction of action potentials down the axon.
myelosuppressionSuppression of bone marrow activity that interferes with the production of all blood cells; causes anemia, increased infections, and bleeding problems.
myocardial infarction (MI)Sudden death of an area of heart muscle, commonly referred to as a heart attack.
myocardiumThe muscular layer of the heart.
myoclonicGeneralized seizures that are usually brief and often confined to one part of the body.
myxedemaCondition associated with a decrease in thyroid function, caused by removal of thyroid tissue or loss of tissue function because of damage to cells; also associated with subcutaneous edema and slowed metabolism.


Na/K adenosine triphosphatase (Na/K ATPase)Enzyme that energizes the sodium/potassium pump and isinhibited by cardiac glycosides.
nativeNatural substance in the body.
nephritisInflammation of the glomeruli often following a streptococcus infection.
nephrosisA degenerative disease of the kidneys, characterized by generalized edema, protein in the urine, and an increase in serum cholesterol.
nerve conductionTransfer of impulses along a nerve by the movement of sodium and potassium ions.
neuroleptanalgesiaCondition in which a patient is quiet and calm and has no response to pain after the combined administration of an opioid analgesic (fentanyl) and a tranquilizer (droperidol).
neuroleptanesthesiaState of unconsciousness plus neuroleptanalgesia produced by the combined administration of nitrous oxide, fentanyl, and droperidol.
neuroleptic malignant syndrome (NMS)Toxic syndrome associated with the use of antipsychotic drugs.
neuromuscular junction (NMJ)Space (synapse) between a motor nerve ending and a skeletal muscle membrane that contains acetylcholine (ACH) receptors.
neuropathic painPain resulting from a damaged nervous system or damaged nerve cells.
neurotransmitterSubstance that stimulates internal organs to produce characteristic changes associated with sympathetic and parasympathetic divisions.
neurotransmitter-gated ion channelIon channels that open or close when a neurotransmitter binds to a receptor.
neutropeniaAn abnormally low number of neutrophils (white blood cells).
nicotineAlkaloid drug in tobacco that stimulates ganglionic receptors.
nicotinic-muscle (Nm) receptorCholinergic receptor located at the neuromuscular junction of skeletal muscle.
nicotinic-neural (Nn) receptorCholinergic receptor at the autonomic ganglia; cholinergic receptor located on both sympathetic and parasympathetic ganglia.
NMJ (neuromuscular junction)Space (synapse) between a motor nerve ending and a skeletal muscle membrane that contains acetylcholine (ACH) receptors.
nociceptorSpecialized peripheral nerve cells sensitive to tissue injury that transmit pain signals to the brain for interpretation of pain.
nonbarbiturateRefers to sedative-hypnotic drugs that do not possess the barbituric acid structure, such as benzodiazepines and related drugs.
nondepolarizing blockerProduces paralysis by inhibiting nerve transmission.
nonopioid analgesicFormerly known as nonnarcotic analgesics, such as NSAIDs and COX-2 inhibitors.
nonprescription, over-the-counter (OTC) drugDrug that can be purchased without the servicesof a physician.
nonselectiveInteracts with any subtype receptor.
nonselective beta-adrenergic blockerDrug that blocks both beta-1 and beta-2 adrenergic receptors.
nonselective beta-adrenergic drugDrug that stimulates both beta-1 and beta-2 receptors.
norepinephrine (NE)Neurotransmitter of sympathetic (adrenergic) nerves that stimulates the adrenergic receptors.
normocytic anemiaAnemia in which RBCs are normal size and usually contain normal hemoglobin but are insufficient to carry adequate oxygen to the tissues; low RBC count.
nosocomialInfection acquired as a result of being in a hospital.
NREM sleepStages of sleep characterized by nonrapid eye movement (NREM).
nucleosideMolecule that contains purine or pyrimidine bases in combination with sugar (ribose or deoxyribose linkage).
numeratorTop number of a fraction; shows the part.


oligospermiaReduced sperm count.
oliguriaCondition in which very small amounts of urine are produced.
on-off phenomenonAlternating periods of movement mobility and immobility.
onychomycosisA fungus infection of the nail; onycho-: pertaining to a claw or nail.
oocystA thick-walled structure in which parasitic protozoal sex cells develop for transfer to new hosts.
oocytethe immature female reproductive cell prior to fertilization.
oogenesisFormation of ova.
opiateDrug derived from opium and producing the same pharmacological effects as opium.
opioidDrug that produces the same pharmacological effects as opium and its family of drugs or the neuropeptides (enkephalin, endorphin) produced by the body.
opioid analgesicsChemically related to morphine or opium and used to relieve pain.
opioid antagonistA drug that attaches to opioid receptors and displaces the opioid analgesic or opioid neuropeptide.
opportunistic organismMicroorganism capable of causing disease only when the resistance (immunocompetence) of the host is impaired.
oral administrationRoute of drug administration by way of the mouth through swallowing.
osmolalityThe concentration of particles dissolved in a fluid.
osmolarityA measure of hydration status; the amount of solute (ions, salts) per liter of solution (blood, plasma).
osmoreceptorsSpecialized cells in the hypothalamus that respond to changes in sodium concentration (osmolarity) in the blood.
osmosisProcess in which water moves across membranes following the movement of sodium ions.
osteoblastsSynthesize bone matrix proteins and promote crystal nucleation; contain receptors for PTH, vitamin D3, and estrogen.
osteoclastsResponsible for bone resorption by binding to bone matrix proteins and releasing enzymes to break down bone.
osteoporosisCondition associated with a decrease in bone density so that the bones are thin and fracture easily; decrease in the bone mineral density, usually in the elderly, that results in areas predisposed to fracture.
ovaMature eggs, also termed oogonia. Ovum is singular; ova is plural.
ovulationRelease of an egg from the ovary.
oxyntic (parietal) cellCell that synthesizes and releases hydrochloric acid (HCl) into the stomach lumen.
oxytocinPolypeptide substance released within the brain that has specific functions during and after pregnancy, specifically relating to the uterus and the mammary glands.


Paget’s diseaseCondition in older adults in which the bone density is altered so that softening and bending of the weight-bearing bones occurs.
parasympatheticRefers to nerves of the ANS that originate in the brain and sacral portion of the spinal cord; they are active when the body is at rest or trying to restore body energy and function.
parasympatholyticRefers to drugs (anticholinergic) that decrease activity of the parasympathetic nervous system.
parasympathomimeticRefers to drugs (cholinergic) that mimic stimulation of the parasympathetic nervous system.
parenteral administrationRoute of drug administration that does not involve the gastrointestinal (GI) tract.
parietal (oxyntic) cellCell that synthesizes and releases hydrochloric acid (HCl) into the stomach lumen.
parkinsonismSymptoms of Parkinson’s disease, which include resting tremor, muscle rigidity, and disturbances of movement and postural balance; disease or druginduced condition characterized by muscular rigidity, tremors, and disturbances of movement.
Parkinson’s diseaseMovement disorder of the basal ganglia caused by a deficiency of dopamine.
partial seizureSeizure originating in one area of the brain that may spread to other areas.
pathogen(ic)Type of bacteria that cause disease; a microorganism that causes disease.
PCT (proximal convoluted tubule)Part of the nephron that is closest to the glomerulus.
penicillinaseBacterial enzymes that inactivate penicillin antibiotics.
pepsinEnzyme that digests protein in the stomach.
percentDecimal fraction with a denominator of 100.
percent compositionCommon measure of solution concentration; refers to grams of solute per 100 ml of solution.
perforationOpening in a hollow organ, such as a break in the intestinal wall.
perimenopauseTwo to ten years before complete cessation of a menstrual period.
peripheral artery disease (PAD)Any disease caused by the obstruction of blood flow in the large arteries of the arms and legs; usually a narrowing and hardening of these arteries that supply the legs and feet.
peripheral nervePart of the nervous system that is outside the central nervous system (the brain or spinal cord), usually near the surface of the tissue fibers or skin.
peripheral resistance (PR)Resistance generated by the flow of blood through the arteries.
peripheral skeletal muscle relaxantDrug that inhibits muscle contraction at the neuromuscular junction or within the contractile process.
peristalsisMovement characteristic of the intestines, in which circular contraction and relaxation propel the contents toward the rectum.
permissiveEnables another hormone to fully function.
perniciousDisease of severe symptoms, which could be fatal if left untreated.
petechiaSmall area of the skin or mucous membranes that is discolored because of localized hemorrhages.
phagocyteCirculating cell (such as a leukocyte) that ingests waste products or bacteria in order to remove them from the body.
pharmacokineticsDescribes the processes of drug absorption, drug distribution, drug metabolism, and drug excretion.
pharmacologyStudy of drugs.
phlebitisInflammation of a vein.
phlegmSecretion from the respiratory tract; usually called mucus.
physical dependenceCondition in which the body requires a substance (drug) not normally found in the body in order to avoid symptoms associated with withdrawal, or the abstinence syndrome.
plaqueSubstance containing cholesterol, dead cell products, and calcium that accumulates in the innermost layer of the arteries.
pluripotentAbility of a substance to produce many different biological responses.
polydipsiaExcessive thirst; increased thirst.
polypeptideSubstance, usually large, composed of an indefinite number of amino acids.
polyphagiaExcessive hunger.
polypharmacyThe situation in patients whose treatment involves multiple drug prescriptions.
polyuriaExcessive urine production; increased urination.
ponsPart of the brainstem that serves as a relay station for nerve fibers traveling to other brain areas; also involved in sensory and motor functions.
porphyria (acute)A genetic disease associated with excessive liver production of delta-aminolevulonic acid and characterized by intermittent hypertension, abdominal cramps, and psychosis.
postpartumAfter childbirth.
postprandialAfter a meal.
potencyMeasure of the strength, or concentration, of a drug required to produce a specific effect.
potentiatesProduces an action that is greater than either of the components can produce alone; synergy.
preferred anestheticProduces adequate anesthesia with minimal side effects.
preloadRefers to venous return, the amount of blood returning to the heart that must be pumped.
premature atrial contraction (PAC)Premature contraction of the atria, usually caused by an ectopic focus.
premature ventricular contraction (PVC)Premature contraction of the ventricles, usually caused by an ectopic focus.
prescription drugDrug for which dispensing requires a written or phone order that can only be issued by or under the direction of a licensed physician.
pressorTending to increase blood pressure.
proarrhythmiaAn arrhythmia caused by administration of an antiarrhythmic drug.
prodrugAn inactive precursor of a drug, converted into its active form in the body by normal metabolic processes.
prohormone (anabolic androgen)After ingestion is converted to the hormone testosterone.
proinflammatoryTending to cause inflammation.
proper fractionFraction that has a value less than 1.
prophylacticProcess or drug that prevents the onset of symptoms (or disease) as a result of exposure before the reactive process can take place.
prophylaxisTreatment or drug given to prevent a condition or disease; procedure or medication to prevent a disease, rather than to treat an existing disease.
proportionA mathematical equation that expresses the equality between two ratios.
prostaglandinSubstance naturally found in certain tissues of the body; can stimulate uterine and intestinal muscle contractions and may cause pain by stimulating nerve endings; chemical mediators released from mast and other cells involved in inflammatory and allergic conditions.
proteolyticAction that causes the decomposition or destruction of proteins.
protozoacidalA substance, chemical solution, or drug that kills protozoa.
protozoanSingle-celled organism belonging to the genus Protozoa.
proximal convoluted tubule (PCT)Part of the nephron that is closest to the glomerulus.
psychomotor stimulantAmphetamine or related drug that increases mental and physical activity.
psychosisForm of mental illness that produces bizarre behavior and deterioration of the personality.
psychotomimetic drugDrug or substance that can induce psychic and behavioral patterns characteristic of a psychosis.
pubertySequence of physiological changes associated with the expression of sexual characteristics and reproductive function that occur when a child progresses into young adulthood, usually at 12 to 14 years of age.


radical cureArresting of malaria, in which protozoal parasites are eliminated from all tissues.
ratioThe relationship of one number to another expressed by whole numbers (1:5) or as a fraction (1/5).
RBCRed blood cell.
receptorSpecific cellular structure that a drug binds to and that produces a physiologic effect.
recombinantGenetically engineered DNA.
referred painOrigin of the pain is in a different location than where the individual feels the pain.
refractoryUnable to produce an increased response even though the stimulation or amount of drug has been increased.
regional nerve blockAlso called nerve block; the injection of a local anesthetic near the nerve root.
REM sleepStage of sleep characterized by rapid eye movement (REM) and dreaming.
remissionPeriod when cancer cells are not increasing in number.
reninEnzyme released by the kidneys that converts angiotensinogen into angiotensin I.
replacement therapyAdministration of a naturally occurring substance that the body is not able to produce in adequate amounts to maintain normal function.
repolarizationReturn of the electric potential across a cell membrane to its resting state following depolarization.
repository preparationPreparation of a drug, usually for intramuscular or subcutaneous injection, that is intended to leach out from the site of injection slowly so that the duration of drug action is prolonged.
reticular formationNetwork of nerve fibers that travel throughout the central nervous system that regulates the level of wakefulness.
Reye’s syndromeA potentially fatal illness characterized by vomiting, an enlarged liver, convulsions, and coma, in children and adolescents; linked to the use of salicylates in the management of influenza, usually type B, or chickenpox.
rhabdomyolysisThe rapid breakdown of skeletal muscle (rhabdomyon) due to muscle injury.
rheumatic feverCondition in which pain and inflammation of the joints or muscles are accompanied by elevated body temperature usually a complication of untreated Strep throat.
rigidityA stiffness and inflexibility of movement.


SASinoatrial, as in the SA node.
salicylismCondition in which toxic doses of salicylates are ingested, resulting in nausea, tinnitus, and delirium.
sarcolemmaA thin membrane enclosing a striated (skeletal) muscle fiber.
sarcoplasmThe cytoplasm of a striated (skeletal) muscle fiber.
sarcoplasmic reticulumSpecialized organelle in the muscle cell that releases calcium ions during muscle contraction and absorbs calcium ions during relaxation.
schizophreniaMajor form of psychosis; behavior is inappropriate.
Schwann cellAny cell that covers the axons in the peripheral nervous system and forms the myelin sheath.
sebumA lipid substance secreted by glands in the skin to lubricate the skin everywhere but the palms and soles.
secondary hypertensionForm of hypertension in which the cause is known.
sedativeDrug used to produce mental relaxation and to reduce the desire for physical activity.
seizureAbnormal discharge of brain neurons that causes alteration of behavior and/or motor activity.
selectiveInteracts with one subtype of receptor over others.
selective beta-1 adrenergic blockerDrug that blocks only beta-1 receptors.
selective beta-2 adrenergic drugDrug that stimulates only beta-2 receptors at therapeutic doses.
selective COX-2 inhibitorsDrugs that only interact with one of the enzymes in the cyclooxygenase family.
sensitizeTo induce or develop a reaction to naturally occurring substances (allergens) as a result of repeated exposure.
side effectDrug effect other than the therapeutic effect that is usually undesirable but not harmful.
site of actionLocation within the body where a drug exerts its therapeutic effect, often a specific drug receptor.
soluteSubstance dissolved in a solvent; usually present in a lesser amount.
solutionHomogeneous mixture of two or more substances.
solventLiquid portion of a solution that is capable of dissolving another substance.
somatomedinsPeptides in the plasma that stimulate cellular growth and have insulin-like activity.
somatostatinAn inhibitory hormone that blocks the release of somatotropin (GH) and thyroid-stimulating hormone (TSH).
somatotropinAnother term for growth hormone (GH).
spasmogenicCausing a muscle to contract intermittently, resulting in a state of spasms.
spasmolyticsDrugs that relieve, interrupt, or prevent muscle spasms (intermittent muscle contractions often associated with pain).
spermatogenesisFormation of spermatozoa.
spermatogoniaIntermediary kind of male germ cell in the production of spermatozoa.
spermatozoaMature sperm cells (singular spermatozoon).
spinal anesthesiaInjection of a local anesthetic into the subarachnoid space.
SSRIsSelective serotonin reuptake inhibitors, a class of antidepressant drugs.
stable plaquePlaque formed in the artery wall that remains in the wall.
-staticSuffix denoting the inhibition of, as of microorganisms.
status epilepticusContinuous series of generalized tonic and clonic seizures, a medical emergency requiring immediate treatment.
sterilizationProcess that results in destruction of all microorganisms.
steroidMember of a large family of chemical substances (hormones, drugs) containing a structure similar to cortisone (tetracyclic cyclopenta-a-phenanthrene).
strokeLoss of brain function due to a loss of blood supply.
stroke volume (SV)Amount of blood pumped per heartbeat.
suppression therapyTaking the drug daily even when there are no observable acute symptoms.
supraventricular arrhythmiaArrhythmia that originates above the AV node in the atria.
suspensionPreparation in which undissolved solids are dispersed within a liquid.
sympatheticRefers to nerves of the ANS that originate from the thoracolumbar portion of the spinal cord; they are active when the body is under stress or when it is exerting energy.
sympatholyticRefers to the action of an adrenergic blocking drug or an action that decreases sympathetic activity.
sympathomimeticRefers to the action of an adrenergic drug or an action that increases sympathetic activity.
synaptic knobContains vesicles that store and release neurotransmitters.
synaptic vesiclesA small membrane-bound structure in the axon terminals of nerve cells that contains neurotransmitters and releases them when an action potential reaches the terminal.
synergisticComplementary or additive.
synergismWhen the action resulting from a combination of drugs is greater than the sum of their individual drug effects.
synesthesiaDistortion of sensory perception; usually associated with the use of LSD.
synthetic drugDrug produced by a chemical process outside the body.
systemicOccurring in the general circulation, resulting in distribution to most organs.


T3 and T4Hormones (triiodothyronine and thyroxine, respectively) synthesized and released by the thyroid gland. Synthesized T4 must be converted to T3 to be utilized by the cell.
tardive dyskinesiaDrug-induced involuntary movements of the lips, jaw, tongue, and extremities.
target organSpecific tissue where a hormone exerts its action.
TCAsTricyclic antidepressants, a class of antidepressant drugs.
tenesmusA painful spasm of the anal sphincter, causing an urgent desire to defecate although little or no material is passed.
teratogenicCapable of causing birth defects or fetal abnormalities or development; capable of causing abnormal development.
tetanyA strong sustained muscle contraction.
tetrahydrocannabinol (THC)Active ingredient of the marijuana plant.
thalamusUppermost part of the brainstem that regulates sensory and motor impulses traveling to and from the cerebral cortex.
therapeutic doseThe amount (dose) of drug required to produce the desired change in the disease or condition.
therapeutic effectDesired drug effect to alleviate some condition or symptom of disease.
therapeutic index (TI)Ratio of the LD50 to the ED50 in animal studies.
thrombocyteCell in the blood, commonly called a platelet, that is necessary for coagulation.
thrombocytopeniaAn abnormal decrease in the number of circulating platelets.
thromboembolismClots that jam a blood vessel; formed by the action of platelets and other coagulation factors in the blood.
thrombophlebitisInflammation of the walls of the veins, associated with clot formation.
thrombusClot formed by the action of coagulation factors and circulating blood cells.
thrushTerm used for Candida infection in the mucous membranes of the mouth and pharynx.
thyrotoxic crisisCondition caused by excessive quantities of thyroid hormone, from either a natural source of hypersecretion or exogenous administration of a drug.
thyroxine (T4)Hormone synthesized and released by the thyroid gland.
TIA (transient ischemic attack)An interruption of blood flow to the brain for a short period of time; a ministroke that produces stroke-like symptoms but no lasting damage.
toleranceAbility of the body to alter its response (to adapt) to drug effects so that the effects are minimized over time.
tonicConvulsive muscle contraction characterized by sustained muscular contractions.
tonic-clonicGeneralized seizure characterized by fullbody tonic and clonic motor convulsions and loss of consciousness.
topical applicationPlacing a drug on the surface of the skin or a mucous membrane (for example, mouth, rectum).
torsade de pointesA type of proarrhythmia that causes ventricular tachycardia and fainting.
toxic effectUndesirable drug effect that implies drug poisoning; can be very harmful or life-threatening.
TPNTotal parenteral nutrition; a combination of nutrients that may include amino acids, carbohydrates, vitamins, and minerals (electrolytes) that is infused into patients who cannot absorb these substances from the gastrointestinal tract because of condition or disease; the combination and concentration of nutrients vary according to patient need.
trade namePatented proprietary name of drug sold by a specific drug manufacturer; also referred to as the brand name.
transdermal absorptionAbsorption of drug (substance) through the skin, usually associated with the application of drug-loaded patches.
transient ischemic attack (TIA)An interruption of blood flow to the brain for a short period of time; a ministroke that produces stroke-like symptoms but no lasting damage.
transit timeAmount of time it takes for food to travel from the mouth to the anus.
tremorA trembling and involuntary rhythmic movement.
TRHThyroid-releasing hormone, secreted by the hypothalamus.
trichomoniasisInfection caused by the Trichomonas organism; a sexually transmitted disease.
triglycerideA fat formed by three fatty acids into one molecule that supplies energy to muscle cells.
triiodothyronine (T3)Hormone synthesized and released by the thyroid gland.
triphasicThe estrogen and progestin amounts released may vary during the cycle.
tropicHaving an affinity for the designated organ; for example, adrenotropic.
tropic hormoneHormone secreted by the anterior pituitary that binds to a receptor on another endocrine gland.
TSHThyroid-stimulating hormone, secreted by the anterior pituitary.
tubular reabsorptionProcess in which the nephrons return to the blood substances (ions, nutrients) that were filtered out of the blood at the glomerulus.
tubular secretionProcess in which the nephrons produce and release substances (ions, acids, and bases) that facilitate sodium ion reabsorption and maintain acid-base balance.
tumorUncontrolled growth of abnormal cells that form a solid mass; also called a neoplasm.
type 1 diabetesInsulin-dependent diabetes mellitus.
type 2 diabetesNon-insulin-dependent diabetes mellitus.


ulcerOpen sore in the mucous membranes or mucosal linings of the body.
ulcerogenicCapable of producing minor irritation or lesions to an integral break in the mucosal lining (ulcer).
unstable plaquePlaque formed in the artery wall that can break away and obstruct blood flow or form a clot.
uremiaAccumulation of nitrogen waste materials (for example, urea) in the blood.
urticariaIntensely itching raised areas of skin caused by an allergic reaction; hives.


vagolytic actionInhibition of the vagus nerve to the heart, causing the heart rate to increase (counteraction to vagal tone that causes bradycardia).
variant or Prinzmetal anginaAngina pectoris caused by vasospasm of the coronary arteries.
vasoconstrictionTightening or contraction of muscles (sphincters) in the blood vessels, which decreases blood flow through the vessels.
vasodilationRelaxation of the muscles (sphincters) controlling blood vessel tone, which increases blood flow through the vessels.
vasodilatorSubstance that relaxes the muscles (sphincters) controlling blood vessels, leading to increased blood flow.
vasopressinMan-made form of ADH. Because of ADH’s fluid reabsorption and vasoconstrictive properties, can elevate blood pressure at higher doses.
ventricular fibrillationThe most serious arrhythmia; usually a terminal event where ventricular contractions are no longer able to effectively pump blood.
very-low-density lipoprotein (VLDL)Molecules made of cholesterol, triglycerides, and protein that carry cholesterol from the liver to organs and tissues; also serves as a precursor to low density lipoproteins (LDL).
virilizationDevelopment of masculine body (hair, muscle) characteristics in females.
virucidalSubstance, chemical solution, or drug that kills viruses; chemical that kills or destroys viruses.


whealA firm, elevated swelling of the skin often pale red in color and itchy; a sign of allergy.


xerostomiaDryness of the oral cavity resulting from inhibition of the natural moistening action of salivary gland secretions or increased secretion of salivary mucus, rather than serous material.