bumetanide
Bumex

Available forms
Available by prescription only
Injection: 0.25 mg/ml
Tablets: 0.5 mg, 1 mg, 2 mg

Indications and dosages
 Edema (heart failure, hepatic and renal disease), postoperative edema ◇, premenstrual syndrome ◇, disseminated cancer ◇. Adults: 0.5 to 2 mg P.O. once daily. If diuretic response isn’t adequate, give a second or third dose at 4- to 5-hour intervals. Maximum daily dose is 10 mg. Give parenterally when oral route isn’t feasible. Usual initial dosage is 0.5 to 1 mg I.V. over 1 to 2 minutes or I.M. If response isn’t adequate, give a second or third dose at 2- to 3-hour intervals. Maximum daily dose is 10 mg.
 Pediatric heart failure ◇. Children: 0.015 mg/ kg every other day to 0.1 mg/kg daily. Use with extreme caution in neonates.
 Hypertension ◇. Adults: 0.5 mg P.O. daily. Oral maintenance of 1 to 4 mg daily; a maximum of 5 mg has been used in patients with normal renal function.
≡ Dosage adjustment. For patients with impaired renal function, oral or I.V. doses up to 20 mg have been administered despite manufacturer recommendations for a maximum of 10 mg daily for the management of edema. For patients with severe chronic renal insufficiency, a continuous infusion of 12 mg over 12 hours may be less toxic and more effective than an intermittent dosing schedule.

Pharmacodynamics
Diuretic action: Loop diuretics inhibit sodium and chloride reabsorption in the proximal part of the ascending loop of Henle, promoting the excretion of sodium, water, chloride, and potassium; bumetanide produces renal and peripheral vasodilation and may temporarily increase glomerular filtration rate and decrease peripheral vascular resistance.

Pharmacokinetics
Absorption: After oral administration, 85% to 95% of dose is absorbed; food delays oral absorption. I.M. bumetanide is completely absorbed.
Distribution: About 92% to 96% protein-bound; it’s unknown whether bumetanide enters CSF or breast milk or crosses the placental barrier.
Metabolism: Metabolized by the liver to at least five metabolites.
Excretion: Excreted in urine (80%) and feces (10% to 20%). Half-life ranges from 1 to 1 1/2 hours.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug or sulfonamides (possible cross-sensitivity), patients with anuria or hepatic coma, and patients in states of severe electrolyte depletion.
  Use cautiously in patients with hepatic cirrhosis and ascites and in those with depressed renal function.

Interactions
Drug-drug. Antihypertensives, diuretics: Potentiates hypotensive effects. These actions may be used to therapeutic advantage.
Indomethacin, probenecid: May reduce diuretic effect of bumetanide. Combined use isn’t recommended; however, if there’s no therapeutic alternative, an increased dose of bumetanide may be needed.
Lithium: Reduces renal lithium clearance and increases lithium levels. Lithium dosage may need adjustment.
Ototoxic or nephrotoxic drugs: May result in increased toxicity. Use together cautiously.
Potassium-depleting drugs, such as amphotericin B and corticosteroids: May cause severe potassium loss. Use together cautiously.
Potassium-sparing diuretics (amiloride, spironolactone, triamterene): May decrease bumetanide-induced potassium loss. Monitor serum potassium levels.
Drug-herb. Dandelion: May interfere with diuretic activity. Discourage use together.

Adverse reactions
CNS: dizziness, weakness, headache, vertigo.
CV: volume depletion and dehydration, orthostatic hypotension, ECG changes, chest pain.
EENT: transient deafness, tinnitus.
GI: nausea, vomiting, upset stomach, dry mouth, diarrhea, pain.
GU: azotemia, renal failure, premature ejaculation, difficulty maintaining erection, oliguria.
Hematologic: thrombocytopenia.
Metabolic: hypokalemia; hypochloremic alkalosis; asymptomatic hyperuricemia; impaired glucose tolerance; hypercholesterolemia; fluid and electrolyte imbalances, including dilutional hyponatremia, hypocalcemia, hypomagnesemia, and hyperglycemia.
Musculoskeletal: arthritic pain, muscle pain and tenderness.
Skin: rash, pruritus, diaphoresis.

Effects on lab test results
• May increase creatinine, uric acid, glucose, and cholesterol levels. May decrease potassium, magnesium, sodium, and calcium levels.
• May decrease platelet count.

Overdose and treatment
Signs and symptoms of overdose include profound electrolyte and volume depletion, which may cause circulatory collapse.
 Treatment is primarily supportive; replace fluid and electrolytes as needed.

Special considerations
• Dilute bumetanide in D₅W, normal saline solution, or lactated Ringer’s solution and use within 24 hours.
• Give I.V. bumetanide slowly, over 1 to 2 minutes, for I.V. infusion.
• Monitor drug effect in patients with renal or hepatic impairment.
• Monitor patient for electrolyte imbalance, especially hypokalemia.
• With increased dose, monitor patient for ototoxicity.
Breast-feeding patients
• Drug shouldn’t be used in breast-feeding women.
Pediatric patients
• Safety and efficacy in children younger than age 18 haven’t been established.
Geriatric patients
• Geriatric and debilitated patients need close observation because they’re more susceptible to drug-induced diuresis. Excessive diuresis promotes rapid dehydration, hypovolemia, hypokalemia, and hyponatremia in these patients, and may cause circulatory collapse. Reduced doses may be indicated.

Patient education
• Tell patient to take drug in the morning to prevent nocturia, and if second dose is prescribed, to take it in early afternoon.
• Instruct patient to take drug with food or milk.
• Advise patient to stand up slowly to prevent dizziness, and to limit alcohol intake and strenuous exercise in hot weather to avoid worsening orthostatic hypertension.
• Instruct patient to weigh himself daily to monitor fluid status.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use