What is the equivalent dose of Bumex (bumetanide) for Lasix (furosemide)?

From the Guidelines

The equivalent dose of Bumex (bumetanide) to Lasix (furosemide) is approximately 1 mg of bumetanide for every 40 mg of furosemide, as indicated by their relative potencies and dosing recommendations in the treatment of heart failure and edema 1. This conversion ratio is crucial when switching patients from one medication to the other, allowing for a more precise adjustment of diuretic therapy based on individual patient responses. Both bumetanide and furosemide are loop diuretics, acting by inhibiting sodium and chloride reabsorption in the ascending loop of Henle in the kidney, which leads to increased urine output and is beneficial in conditions like heart failure and edema. Key differences between the two medications include their oral bioavailability, with bumetanide having around 80-100% bioavailability compared to furosemide's 50-60% 1. This higher bioavailability of bumetanide may offer advantages in certain clinical scenarios, such as in patients with compromised gut absorption. However, regardless of which medication is used, monitoring for potential side effects, including electrolyte imbalances (notably potassium depletion), is essential. The dosing of these medications can be adjusted based on patient response, with the goal of achieving optimal diuretic effect while minimizing adverse effects, as outlined in guidelines for the management of heart failure 1. In clinical practice, the choice between bumetanide and furosemide, as well as the dosing strategy, should be tailored to the individual patient's needs and response, considering factors such as the severity of heart failure, renal function, and the presence of any conditions that might affect drug absorption or efficacy.

From the FDA Drug Label

Pharmacological and clinical studies have shown that 1 mg bumetanide has a diuretic potency equivalent to approximately 40 mg furosemide. The equivalent dose of Bumex (bumetanide) for Lasix (furosemide) is:

• 1 mg Bumex = 40 mg Lasix This means that for every 1 mg of Bumex, you would need approximately 40 mg of Lasix to achieve the same diuretic effect 2.

From the Research

Equivalent Dose of Bumex for Lasix

The equivalent dose of Bumex (bumetanide) for Lasix (furosemide) can be determined based on their relative potencies.

• Bumetanide is approximately 40-fold more potent than furosemide, as stated in the study 3.
• This means that 1 mg of bumetanide is equivalent to 40 mg of furosemide.
• Another study 4 found that bumetanide is approximately 50 times as potent as furosemide on a milligram basis.

Clinical Applications

In clinical practice, the dose ratio of bumetanide to furosemide is often used to guide equivalent dosing.

• A study 3 found that oral or intravenous bumetanide 0.5 to 2 mg/day produces results comparable to those with furosemide 20 to 80 mg/day.
• Another study 5 found that the mean diuretic doses of 172 and 4.3 mg for furosemide and bumetanide, respectively (ratio = 40:1) were sufficient to produce a maximum response.

Special Considerations

It's worth noting that the equivalent dose of bumetanide for furosemide may vary depending on the specific clinical context and patient population.

• For example, in patients with chronic renal insufficiency, the dose of bumetanide may need to be adjusted due to its reduced renal clearance, as noted in the study 6.
• Additionally, the study 7 highlights the importance of considering the pharmacokinetics and pharmacodynamics of both drugs in neonates and infants when determining equivalent dosing.