Acetazolamide inhibits carbonic anhydrase, an enzyme crucial for bicarbonate reabsorption in the proximal renal tubules. This inhibition reduces bicarbonate reabsorption, leading to increased bicarbonate excretion in the urine. Consequently, more sodium and water are excreted, resulting in diuresis and a decrease in intraocular pressure.
Absorption after oral administration is rapid and complete. Peak plasma concentrations typically occur within 2 hours. The drug readily distributes into various body fluids, including cerebrospinal fluid. Acetazolamide is primarily metabolized in the liver, with a significant portion excreted unchanged in the urine. Its elimination half-life is approximately 4-13 hours.
| Bioavailability (Oral) | ~80% |
| Protein Binding | 10-25% |
| Elimination Half-life | 4-13 hours |
| Metabolism | Hepatic |
| Excretion | Renal (primarily unchanged) |
Dosage adjustments may be necessary in patients with impaired renal function due to prolonged elimination. Close monitoring of electrolyte levels, particularly potassium, is recommended, as hypokalemia is a potential side effect. The drug’s diuretic effect can also cause dehydration; adequate fluid intake is therefore advised.
