Tolvaptan Side Effects ADPKD — ESENeph MCQ

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EasyPolycystic Kidney DiseaseTolvaptan Side Effects ADPKDESENeph

A 45-year-old woman with ADPKD has eGFR 55 and is being considered for Tolvaptan. She asks about the common side effects. What is the most frequent adverse effect?

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Correct answer: E — Aquaresis: polyuria, polydipsia, nocturia, and thirst – due to blocking V2 vasopressin receptors causing water diuresis

Tolvaptan blocks vasopressin V2 receptors in the collecting duct, preventing water reabsorption. This causes significant aquaresis (water diuresis) with polyuria (up to 6-8 L/day initially), thirst, and nocturia. Patients must be able to drink freely. These effects are predictable pharmacological consequences, not adverse reactions. They often improve with time. Hepatotoxicity is rarer but more serious and requires LFT monitoring. Hypernatraemia is uncommon with adequate fluid intake.

Reference: NICE TA877 2022 – Tolvaptan; TEMPO 3:4 Trial Safety Data