From the FDA Drug Label
For diuresis in congestive heart failure, the starting dose is usually 250 to 375 mg once daily in the morning (5 mg/kg) If, after an initial response, the patient fails to continue to lose edema fluid, do not increase the dose but allow for kidney recovery by skipping medication for a day. Acetazolamide yields best diuretic results when given on alternate days, or for two days alternating with a day of rest.
The recommended dosage of Diamox (Acetazolamide) for use in Congestive Heart Failure (CHF) is:
- Starting dose: 250 to 375 mg once daily in the morning (5 mg/kg)
- Administration: On alternate days, or for two days alternating with a day of rest, to allow for kidney recovery 1
From the Research
Diamox (acetazolamide) is typically dosed at 250-500 mg orally once or twice daily when used as an adjunctive therapy for congestive heart failure (CHF), as supported by the most recent study 2.
Key Considerations
- Treatment can be initiated at 250 mg daily and titrated up if needed based on clinical response.
- For acute exacerbations, some clinicians may use up to 500 mg daily, divided into two doses.
- The medication should be taken in the morning to avoid nighttime diuresis and subsequent sleep disruption.
- Patients should be monitored for metabolic acidosis, electrolyte imbalances (particularly potassium and sodium), and renal function during treatment.
Mechanism and Benefits
- Diamox works as a carbonic anhydrase inhibitor, promoting sodium and bicarbonate excretion in the kidneys, which leads to mild diuresis and metabolic acidosis.
- This metabolic acidosis can help counteract respiratory alkalosis often seen in CHF patients with chronic respiratory compensation.
- Diamox is particularly useful in patients with diuretic resistance or those with concurrent respiratory alkalosis, though it is generally considered a second or third-line agent after traditional loop diuretics, thiazides, and potassium-sparing diuretics have been optimized, as noted in studies 3, 4.
Clinical Evidence
- A recent study 2 aims to assess the efficacy of acetazolamide combined with loop diuretics in achieving decongestion among patients who fail to respond to oral diuretics and progress to acute decompensated heart failure.
- Another study 3 determined the short- and long-term effects of acetazolamide on peripheral blood, serum electrolytes, and renal function, showing its potential as a chloride-regaining diuretic.
- The use of acetazolamide in refractory congestive heart failure has been evaluated 4, showing improvement in functional class and surrogates of fluid overload.