What is the equivalent dose of Lasix (furosemide) for Bumex (bumetanide) 2 mg?

From the Guidelines

The equivalent dose of Lasix (furosemide) for Bumex (bumetanide) 2 mg is 80 mg. Bumetanide is approximately 40 times more potent than furosemide, with a standard conversion ratio of 1 mg bumetanide being equivalent to 40 mg furosemide, as seen in the guidelines for the diagnosis and management of heart failure in adults 1.

Key Points to Consider

• The conversion ratio is based on the potency of bumetanide compared to furosemide, with bumetanide being more potent.
• When switching between these loop diuretics, it's essential to monitor the patient closely for the desired therapeutic effect and potential side effects, as individual responses may vary.
• Both medications work by inhibiting sodium and chloride reabsorption in the ascending loop of Henle, but bumetanide has better bioavailability and more predictable absorption than furosemide, which may be relevant in patients with certain conditions like heart failure or renal impairment.
• Dosing adjustments may be necessary based on the patient's clinical response, renal function, and electrolyte status, as excessive use of diuretics can lead to complications such as electrolyte depletion, hypotension, and azotemia 1.

Clinical Implications

• The risk of electrolyte depletion is markedly enhanced when two diuretics are used in combination, and concomitant administration of ACEIs alone or in combination with potassium-retaining agents can help prevent electrolyte depletion in most patients with heart failure who are taking a loop diuretic 1.
• Close monitoring and adjustment of diuretic doses are crucial to avoid adverse effects and ensure optimal management of heart failure.

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 Lasix (furosemide) for Bumex (bumetanide) 2 mg is approximately 80 mg of furosemide, since 1 mg of bumetanide is equivalent to 40 mg of furosemide 2.

• Key points:
  • 1 mg bumetanide ≈ 40 mg furosemide
  • 2 mg bumetanide ≈ 80 mg furosemide

From the Research

Equivalent Dose of Lasix (Furosemide) for Bumex (Bumetanide) 2 mg

• The equivalent dose of Lasix (furosemide) for Bumex (bumetanide) 2 mg can be determined based on the potency ratio between the two drugs.
• Studies have shown that bumetanide is approximately 40-fold more potent than furosemide 3, 4.
• Based on this ratio, a dose of 2 mg bumetanide is equivalent to 80 mg furosemide (2 mg x 40) 3, 4.
• Another study found a potency ratio of 41:1 for intermittent intravenous administration and 34:1 for all patients with heart failure 4.
• However, the exact equivalent dose may vary depending on the individual patient and the specific clinical context.

Clinical Considerations

• The diuretic effect of both bumetanide and furosemide is short-lived, with peak natriuresis occurring within 30 minutes to 1 hour after administration 5, 6.
• The time course of response shows that the curves are virtually superimposable for both drugs 5.
• The sodium/potassium ratio was calculated to be approximately 200:35 for bumetanide and 200:50 for furosemide, indicating a slightly lower potassium excretion with bumetanide 5.
• Electrolyte replacement may be necessary during therapy with either drug, especially in patients at risk of hypokalaemia 4.