From the Guidelines
The combination of acetazolamide and Lasix (furosemide) should be used with caution due to the risk of hypovolaemia, hypotension, hypokalaemia, and renal impairment, as highlighted in the 2012 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 1. When considering the use of these medications together, it's essential to understand their mechanisms of action and potential interactions. Acetazolamide is a carbonic anhydrase inhibitor that promotes bicarbonate excretion, while furosemide is a loop diuretic that blocks sodium reabsorption in the loop of Henle.
- Key considerations for their combined use include:
- Monitoring electrolyte levels, particularly potassium, sodium, and bicarbonate
- Assessing kidney function and fluid status
- Risk of significant electrolyte imbalances and dehydration
- Potential for hypotension, especially when combined with other medications like ACE inhibitors, ARBs, or renin inhibitors 1
- Patients should be advised to stay well-hydrated and report symptoms like excessive thirst, dizziness, muscle cramps, or irregular heartbeat. The typical dose of acetazolamide ranges from 250-500 mg once or twice daily, while furosemide is typically dosed at 20-80 mg once or twice daily. However, when used together, careful titration and monitoring are necessary to minimize adverse effects.
- It's crucial to weigh the benefits of combined diuretic therapy against the potential risks and to consider alternative treatment strategies, especially in patients with pre-existing renal impairment or those taking other medications that may interact with diuretics 1.
From the Research
Acetazolamide and Lasix Comparison
- Acetazolamide is a carbonic anhydrase inhibitor used for the prevention and treatment of acute mountain sickness (AMS) 2, 3, 4, 5.
- Lasix, also known as furosemide, is a loop diuretic commonly used to treat fluid overload in patients with heart failure 6.
- While acetazolamide has been shown to be effective in preventing AMS, its use as a diuretic in heart failure patients has also been explored, with studies suggesting it can produce an additional diuretic effect when used in conjunction with other diuretics 6.
- In contrast, Lasix is a more potent diuretic, but its use in AMS prevention has not been established.
- The dosage of acetazolamide for AMS prevention varies, with studies suggesting doses ranging from 125mg to 750mg per day 2, 3, 4.
- For heart failure patients, acetazolamide has been used as an add-on diuretic therapy, with a dose-adjusted to body weight 6.
Mechanism of Action
- Acetazolamide works by inhibiting carbonic anhydrase, an enzyme that plays a crucial role in the regulation of fluid and electrolyte balance in the body 2, 3, 4, 5.
- Lasix, on the other hand, works by inhibiting the sodium-potassium-chloride cotransporter in the loop of Henle, leading to increased urine production and diuresis 6.
Clinical Applications
- Acetazolamide is commonly used for the prevention and treatment of AMS, as well as for the treatment of glaucoma, epilepsy, and other conditions 2, 3, 4, 5.
- Lasix is primarily used for the treatment of fluid overload in patients with heart failure, as well as for the treatment of hypertension and edema 6.
- The use of acetazolamide as a diuretic in heart failure patients may be considered in certain cases, particularly when other diuretics are not effective or are contraindicated 6.