Acetazolamide is used to prevent acute mountain sickness (AMS). The mechanism by which it accelerates acclimatization involves:

• A Increasing respiratory drive by acidifying plasma, compensating for the alkalosis that normally suppresses ventilation at altitude ✓
• B Reducing cerebrospinal fluid production, decreasing intracranial pressure-related headache
• C Increasing renal bicarbonate reabsorption to compensate for the respiratory alkalosis of altitude
• D Inhibiting carbonic anhydrase in erythrocytes, enhancing oxygen delivery from hemoglobin

Explanation

At altitude, hypoxia stimulates ventilation (hyperventilation), causing respiratory alkalosis (elevated pH, reduced pCO2). This alkalosis activates central and peripheral chemoreceptors to reduce respiratory drive, blunting the ventilatory response — the principal pathophysiology of AMS. Acetazolamide inhibits carbonic anhydrase in the proximal tubule, causing urinary bicarbonate loss and metabolic acidosis. This acidosis stimulates breathing (overcoming the alkalosis-induced ventilatory blunting) and accelerates acclimatization to altitude.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.