What is the recommended fluid restriction window around desmopressin 240 microgram oral lyophilisate?

• A. Avoid fluids for 1 hour before and 8 hours after
• B. Do not take any fluids before dosing
• C. Avoid foods
• D. Drink plenty of fluids

Answer: (A)

Desmopressin works by making the kidneys reabsorb more water, so it can lower the body's free water excretion and raise the risk of hyponatremia if fluid intake is not controlled. With the oral lyophilisate, the antidiuretic effect starts within about an hour and can persist for several hours. Limiting fluids for one hour before dosing and for eight hours after dosing helps ensure that the period of peak water-retaining effect occurs while fluid intake is restricted, reducing the chance of dangerous water retention and low sodium.

Options suggesting no fluids at all before dosing, avoiding foods, or drinking plenty of fluids don’t address this balance and could either be unnecessary or harmful.