Generic Name

bumetanide

Brand Names

for bumetanide, a potent loop diuretic used in the management of fluid overload.

Mechanism

• Inhibits the Na⁺‑K⁺‑2Cl⁻ cotransporter (NKCC2) in the thick ascending limb of the loop of Henle.
• Blocks reabsorption of Na⁺, K⁺, and Cl⁻, leading to osmotic diuresis and natriuresis.
• Decreases the reabsorption of Ca²⁺ and Mg²⁺, causing mild hypocalcemia and hypomagnesemia.

Pharmacokinetics

• Absorption: Rapid oral absorption; bioavailability ~50 %.
• Distribution: Highly lipophilic; crosses the blood‑brain barrier.
• Metabolism: Metabolized by the liver (CYP2C9, CYP3A4).
• Excretion: Primarily renal (70‑80 % unchanged); half‑life ≈ 0.9–1.3 h.
• Drug interactions:
• Potentiated diuretic effect with NSAIDs, salt‑sparing diuretics, ACE inhibitors, and ARBs.
• Reduced clearance when combined with metformin (possible lactic acidosis).

Indications

• Congestive heart failure – acute decompensation and chronic volume overload.
• Pulmonary edema – including cardiogenic and non‑cardiogenic causes.
• Edema associated with hepatic cirrhosis (ascites).
• Renal disease requiring aggressive diuresis (e.g., acute tubular necrosis when fluid overload is present).

Contraindications

• Absolute contraindication: Hypersensitivity to bumetanide.
• Use with caution:
• Severe renal impairment (CrCl <20 mL/min).
• Severe hepatic cirrhosis with high bilirubin.
• Hypotension, hypovolemia, or volume depletion.
• Congenital or acquired electrolyte disorders (e.g., severe hypokalemia).
• Warnings:
• Monitor for ototoxicity (rare at therapeutic doses).
• Avoid in patients with pre‑existing deafness.

Dosing

• Administer in the morning to reduce nocturia.
• Intravenous form: 0.1–0.5 mg IV over 10‑15 min; titrate to desired diuresis.

Monitoring

• Daily: Weight, urine output, serum electrolytes (Na⁺, K⁺, Cl⁻, Mg²⁺, Ca²⁺).
• Blood pressure every visit (or more frequently if unstable).
• Renal function (serum creatinine, BUN, CrCl) at baseline and periodically.
• Hearing assessment if prolonged or high‑dose therapy.

Clinical Pearls

• Potent diuretic: Bumetanide is 10–15× more potent than furosemide; a 2–3 mg dose often equals 80 mg furosemide.
• Sparing sodium: Because it blocks Na⁺ reabsorption in multiple segments, even modest sodium loads can be excreted.
• Use with potassium‑sparing agents (spironolactone, amiloride) as prophylaxis against hypokalemia.
• Ototoxicity risk: Dose‑response relationship; monitor hearing in patients with renal disease or concomitant aminoglycosides.
• Gout prophylaxis: Consider allopurinol or febuxostat when initiating or escalating bumetanide therapy.
• Avoid sudden withdrawal – it can precipitate acute decompensation in heart failure patients.

--
• Key Terms: *Bumetanide, Bumex, loop diuretic, NKCC2, natriuresis, electrolyte imbalance, ototoxicity, hypokalemia.*