Flight Surgeon Module B Practice Test 2026 - Free Practice Questions and Study Guide

Diamox works by inhibiting the enzyme carbonic anhydrase. In the kidney this prevents reabsorption of bicarbonate, causing bicarbonate-rich urine and a mild metabolic acidosis (pH drop). That acid-base shift stimulates the respiratory center to increase ventilation, which improves arterial oxygenation at altitude and helps relieve AMS symptoms. There’s also a contribution from reduced CSF production due to carbonic anhydrase inhibition, which can help lessen cerebral edema. The other options don’t reflect this mechanism: the drug doesn’t increase oxygen-carrying capacity, directly reduce cerebral blood flow as the primary effect, or stimulate respiration by directly activating chemoreceptors—the trigger is the metabolic acidosis-driven rise in breathing.