From the FDA Drug Label
Acetazolamide is a potent carbonic anhydrase inhibitor, effective in the control of fluid secretion... and in the promotion of diuresis in instances of abnormal fluid retention The diuretic effect of acetazolamide is due to its action in the kidney on the reversible reaction involving hydration of carbon dioxide and dehydration of carbonic acid The result is renal loss of HCO3 ion, which carries out sodium, water, and potassium. Alkalinization of the urine and promotion of diuresis are thus affected.
The role of acetazolamide in metabolic alkalosis is not directly supported by the provided drug label information. However, based on its mechanism of action, acetazolamide can increase the renal loss of HCO3 ion, which could potentially help in treating metabolic alkalosis by increasing the excretion of bicarbonate.
- Key points:
- Acetazolamide inhibits carbonic anhydrase.
- Inhibition of carbonic anhydrase leads to renal loss of HCO3 ion.
- Renal loss of HCO3 ion could help in treating metabolic alkalosis. 1
From the Research
Acetazolamide is a recommended treatment for metabolic alkalosis, particularly in cases resistant to chloride replacement therapy, with a typical dose ranging from 250-500 mg given orally or intravenously every 6-12 hours until alkalosis resolves, as supported by the most recent study 2.
Mechanism of Action
Acetazolamide works as a carbonic anhydrase inhibitor that blocks the enzyme responsible for reabsorbing bicarbonate in the proximal tubule of the kidney. This mechanism promotes bicarbonate excretion in the urine, effectively lowering serum bicarbonate levels and helping correct the alkalotic state.
Clinical Use
The medication is particularly useful in patients with volume overload or heart failure where additional fluid administration would be problematic. However, acetazolamide should be used cautiously in patients with significant renal impairment, liver disease, or electrolyte abnormalities, especially hypokalemia, as it can worsen these conditions.
- Key patient populations that may benefit from acetazolamide include those with heart failure, as shown in a study comparing intravenous and oral acetazolamide 3.
- Critically ill pediatric patients may also be treated with acetazolamide, although its effectiveness in cardiac patients is less clear 4.
- The safety profile of acetazolamide has been evaluated, and it is considered an overall safe drug if administered to correctly selected patients 5.
Monitoring and Administration
Potassium levels should be monitored and repleted as needed during treatment, as acetazolamide can increase potassium excretion. The medication typically begins working within hours, with maximum effect seen within 24-48 hours of administration.
- The optimal route of administration may be intravenous, as suggested by a study showing significant decreases in bicarbonate levels within 24 hours of IV acetazolamide administration 3.