The Question

We asked you the following question on our Instagram stories today – what name is given to a drug that promotes water loss without loss of electrolytes?

  1. Antipyretic
  2. Diuretic
  3. Soporific
  4. Aquaretic

The correct answer here is d. Aquaretic.

Why?

Many of you chose “diuretic”, probably because “water loss” was in the question and you only have a few seconds to select an answer. Pressure alone may have caused you to opt for the wrong answer.

Of course, diuretic was included as a trick answer.

Diuretics do promote water loss, but they also promote loss of electrolytes. The same cannot be said for an “aquaretic”; a drug that promotes water loss without loss of electrolytes. That’s the fundamental difference.

Tolvaptan is a perfect example of an aquaretic drug.

What is tolvaptan?

The pharmacology of tolvaptan involves competitive antagonism of the vasopressin V2 receptor.

Because tolvaptan can promote water loss without electrolyte loss, the drug is used to treat hyponatremia associated with conditions such as heart failure and cirrhosis and SIADH – syndrome of inappropriate antidiuretic hormone secretion.

Tolvaptan should not be used for more than 30 days. It should also be avoided in patients with established hepatic disease as it may amplify liver damage and can, in some cases, develop into liver failure.

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