Ribavirin Pharmacology

Here, we review the fundamental facts about ribavirin pharmacology; an important medicine in the clinical pharmacology of antiviral drugs. It is used in the treatment of a wide range of viral infections, but it also comes with significant side effects and notable contraindications, particularly in the context of pregnancy.

Let’s take a few minutes to review the fundamental facts you need to know.

Indications

Ribavirin is an antiviral medicine used in the treatment of:

  • RSV infection – respiratory syncytial viral infection
  • Hepatitis C
  • Viral hemorrhagic fever – Lassa fever, Crimean-Congo hemorrhagic fever and Hantavirus infection

In the case of hepatitis C, ribavirin is used alongside other medicines including:

  • Sofosbuvir
  • Simeprevir
  • Peginterferon alfa-2b
  • Peginterferon alfa-2a

Ribavirin came into use in 1986 and has since been listed on the WHO List of Essential Medicines.

Brand names: Copegus, Rebetol, Moderiba, Virazole

Mechanism of action

Mechanistically, ribavirin works as follows:

  • At the most fundamental level, ribavirin works by suppressing viral RNA synthesis and mRNA capping – in this regard, then, ribavirin acts as a nucleoside inhibitor.
  • Chemically, ribavirin is an analog of the purine nucleoside, guanosine.
  • Ribavirin is also a prodrug. It is metabolised into active ingredients that almost mimic purine RNA nucleotides; nucleotides which serve to interfere with viral RNA synthesis.

Side effects

Clinically significant side effects of ribavirin include:

  • Anemia
  • Chest pain
  • Neutrophil deficiency
  • Hemolytic anemia
  • Difficulty breathing (dyspnea)
  • Hepatotoxicity

Other less severe side effects include flu-like symptoms, dizziness, headache, muscle pain and aches, low energy, weakness, irritability and mood swings.

Clinical considerations

Clinically considerations with ribavirin include:

  • Due to the active risk of birth defects, at least two forms of contraception should be used for at least 6 months in the post-treatment phase. Protection is also warranted during the treatment phase, too.
  • Ribavirin is not effective when used alone for hepatitis C. It is typically used alongside another drug, such as peginterferon.
  • Ribavirin should be taken with food.
  • To prevent dehydration, patients should consume adequate fluids.
  • Alcohol increases the risk of hepatotoxicity.
  • Ribavirin interacts with drugs used to treat HIV/AIDs. For example – there is an increased risk of anemia when ribavirin is taken with zidovudine There is also an increased risk of mitochondrial toxicity when ribavirin is taken with didanosine, another antiretroviral drug. Ribavirin increases the risk of hepatotoxicity when taken with other antiretroviral drugs.

For even more facts and quiz questions on ribavirin pharmacology, register with PharmaFactz today. Check back to our pharmacy blog soon for even more great facts on ribavirin and other features of antiviral drugs pharmacology!