Torasemid

Torsemide (also spelled torasemid in some languages) is a loop diuretic of the sulfonamide class used to treat edema from congestive heart failure, liver cirrhosis, and nephrotic syndrome, and to manage hypertension in selected patients. It is generally preferred for its higher and more predictable oral bioavailability and longer duration of action compared with furosemide.

Mechanism of action: Torsemide inhibits the Na+/K+/2Cl- cotransporter ( NKCC2 ) in the thick ascending limb of the loop of Henle, increasing the excretion of sodium, chloride, potassium, and calcium. The result is rapid diuresis and natriuresis, reducing extracellular fluid volume and edema.

Pharmacokinetics: When taken by mouth, torsemide is well absorbed with an onset in about 60 to 90 minutes; intravenous administration yields a faster onset. The elimination half-life is about 3 to 4 hours in healthy adults, with a diuretic effect lasting roughly 6 to 8 hours. It is largely metabolized in the liver and mainly excreted by the kidneys.

Indications and administration: It is used to treat edema associated with heart failure, liver cirrhosis, and nephrotic syndrome, and may be used for resistant hypertension in some contexts. Dosing should be individualized based on renal function and fluid status; contraindicated in anuria and in conditions of electrolyte depletion. Electrolyte monitoring is advised.

Safety and interactions: Potential adverse effects include dehydration, hypotension, hypokalemia, hyponatremia, and ototoxicity at high doses or with other ototoxic drugs. NSAIDs can reduce diuretic efficacy; caution is advised when co-administering with aminoglycosides or lithium.