From the FDA Drug Label
Acetazolamide is an enzyme inhibitor that acts specifically on carbonic anhydrase, the enzyme that catalyzes the reversible reaction involving the hydration of carbon dioxide and the dehydration of carbonic acid 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.
To manage metabolic alkalosis with a high pH, low CO2 (carbon dioxide), and elevated bicarbonate level, consider using acetazolamide.
- The medication can help promote diuresis and increase the renal loss of HCO3 ion, which can aid in correcting the alkalosis.
- Acetazolamide works by inhibiting carbonic anhydrase, an enzyme involved in the regulation of bicarbonate levels in the body 1. The goal of treatment is to normalize the pH and bicarbonate levels, and acetazolamide may be a useful adjunct in achieving this goal.
From the Research
To manage metabolic alkalosis with a high pH of 7.5, low CO2 of 25, and elevated bicarbonate level of 20, administer isotonic saline (0.9% NaCl) at 100-200 mL/hour to correct volume depletion and promote bicarbonate excretion, as recommended by the most recent study 2. The goal is to normalize pH by addressing the acid-base imbalance gradually. Key steps include:
- Identifying and treating the underlying cause, which commonly includes vomiting, diuretic use, or hypokalemia
- Correcting electrolyte imbalances, particularly potassium deficiency, with IV potassium chloride (typically 10-20 mEq/hour, not exceeding 40 mEq/hour) while monitoring serum levels
- Considering acetazolamide 250-500 mg orally or IV every 6 hours to increase bicarbonate excretion for severe cases (pH > 7.60)
- Using dilute hydrochloric acid (0.1-0.2 N HCl) administered through a central line at 10-15 mL/kg over 24 hours for severe cases
- Employing potassium-sparing diuretics like spironolactone (25-100 mg daily) in cases of chloride-resistant alkalosis Treatment should focus on replacing chloride ions, suppressing renal bicarbonate reabsorption, and restoring normal acid-base homeostasis, as outlined in 2, the most recent and highest quality study. It is essential to continuously monitor cardiac function, especially when correcting electrolytes, to prevent complications such as cardiac arrhythmias and neurological issues, as noted in 3 and 4. By following these steps and prioritizing the most recent evidence 2, it is possible to effectively manage metabolic alkalosis and improve patient outcomes.