Torsemide

Torsemide, sold under brand name Demadex among others, is a loop diuretic in the sulfonamide class used to reduce fluid overload. It is indicated for edema associated with heart failure, hepatic cirrhosis, and nephrotic syndrome, and is also used in the management of hypertension in certain patients. It is available in oral tablet form and as an injectable solution.

Mechanism of action: Inhibits the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, promoting excretion of sodium, chloride, potassium, calcium, and water; leads to decreased extracellular fluid volume and reduced edema and blood pressure. Because it depletes potassium, monitoring electrolytes is needed.

Pharmacokinetics: Torsemide is well absorbed when taken by mouth; oral bioavailability is high; onset of diuresis is within about an hour, with peak effects within a couple of hours; intravenous administration acts more rapidly. It has a longer duration of action than furosemide and is extensively protein-bound; primarily cleared by the liver with metabolites excreted in urine.

Dosing and administration: Dosing is individualized based on indication and response; initial therapy often starts with a low dose and titrates upward. In edema associated with heart failure or liver disease, monitoring of fluid status and electrolytes is essential. Caution is advised in patients with kidney impairment, dehydration, or low blood pressure. Many patients should avoid concomitant NSAID therapy, which can reduce diuretic effectiveness.

Side effects and safety: Common adverse effects include volume depletion, hypotension, dehydration, dizziness, and electrolyte disturbances such as hypokalemia and hyponatremia; ototoxicity is rare but possible with rapid IV administration or high doses. Hypersensitivity to sulfonamides is a precaution; torsemide is contraindicated in anuria.