Torsemide: A Pyridine-Sulfonylurea Loop Diuretic

OBJECTIVE: To review the clinical pharmacology of torsemide and to compare it with currently available loop diuretics, particularly furosemide. DATA SOURCES: An English-language MEDLINE search, 1985 to October 1994, was used to identify pertinent literature, including review articles. DATA EXTRACTION: Data from scientific literature were extracted, evaluated, and summarized for presentation. Pivotal and representative studies are discussed relating to the pharmacology, pharmacokinetics, and use of torsemide in patients with congestive heart failure, renal disease, hepatic disease, and hypertension. DATA SYNTHESIS: Torsemide is a loop diuretic of the pyridine-sulfonylurea class. The bioavailability of torsemide is approximately 80%, with little first-pass metabolism, and torsemide can be given without regard to meals. The serum concentration reaches its peak within 1 hour after oral administration and diuresis lasts approximately 6-8 hours. Torsemide is eliminated both hepatically (80%) and renally (20%) as unchanged drug with an elimination half-life of about 3.5 hours. Because of the high bioavailability, oral and intravenous doses are therapeutically equivalent. Torsemide, and other loop diuretics such as furosemide, are indicated for the treatment of edema associated with congestive heart failure, renal disease, and hepatic disease. They also are indicated for the treatment of hypertension alone or in combination with other antihypertensive agents. Depending on the indication, the recommended initial adult dosage of torsemide is between 5 and 20 mg once daily orally or intravenously. Special dosage adjustments in the elderly are not necessary. CONCLUSIONS: Torsemide is a loop diuretic similar to furosemide, with similar indications. Torsemide is characterized by good bioavailability and once-daily dosing and, compared with furosemide, provides generally equivalent therapeutic efficacy.