Name: Bumetanide (Bumex)
Class: Diuretic (Loop Diuretic)
Mechanism: Blocks the Na+/K+/Cl- co-transporter in the apical membrane of the thick ascending limb of Henle’s loop ® excretion of urinary water, Na+, K+, Ca2+, & Mg2+. Also causes venous and renal vasodilation.
Absorption: Oral, IV. Takes effect in 20 min.
Dist.: Metabolism.:
Excretion, t½: 1-1.5 hr.
Toxicity/S.E.s: Hypokalemia (esp. dangerous if pt. is on digitalis), Ca2+ & Mg2+ depletion, Metabolismolic alkalosis, volume contraction, mild hyperglycemia, sulfonamide allergy cross-rxn, ototoxicity. C/i—pts. susceptible to volume contraction from excessive diuresis (e.g., elderly), and pts. susceptible to problems w/hypokalemia (e.g., cirrhosis, pts. taking digitalis).
Utility: Diuresis for hypertension when a short-acting diuretic is indicated. Very useful in conditions refractory to less potent diuretics, including CHF, renal insufficiency, and nephrotic synd. Also used to treat hypercalcemia.
Special Features: Most potent diuretics available. Far more potent than furosemide. Can cause excretion of up to 20% of filtered Na+.