Torsemide

Brand Names: Torsemide

Drug Class: Loop Diuretic

Overview

11 DESCRIPTION Torsemide, USP is a diuretic of the pyridine-sulfonylurea class. Its chemical name is 1-isopropyl-3-[(4-m-toluidino-3-pyridyl) sulfonyl]urea and its structural formula is: Its molecular formula is C 16 H 20 N 4 O 3 S, its pKa is 7.1, and its molecular weight is 348.43. Torsemide, USP is a white to off-white crystalline powder.

Mechanism of Action

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Micropuncture studies in animals have shown that torsemide acts from within the lumen of the thick ascending portion of the loop of Henle, where it inhibits the Na + /K + /2Cl – -carrier system. Clinical pharmacology studies have confirmed this site of action in humans, and effects in other segments of the nephron have not been demonstrated. Diuretic activity thus correlates better with the rate of drug excretion in the urine than with the concentration in the blood. Torsemide increases the urinary excretion of sodium, chloride, and water, but it does not significantly alter glomerular filtration rate, renal plasma flow, or acid-base balance. 12.

Indications

  • 1 INDICATIONS AND USAGE Torsemide is a loop diuretic indicated for: the treatment of edema associated with heart failure, renal disease or hepatic disease. ( 1.1 ) the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. ( 1.2 ) 1.1 Edema Torsemide tablets are indicated for the treatment of edema associated with heart failure, renal disease or hepatic disease. 1.

Common Doses

  • 20 mg
  • 200 mg
  • 10 mg
  • 40 mg

Dosage

2 DOSAGE AND ADMINISTRATION Edema associated with: Heart failure: Initial dose is 10 or 20 mg once daily. Titrate by factors of two; doses above 200 mg have not been studied. ( 2.1 ) Chronic Renal Failure: Initial dose is 20 mg once daily. Titrate by factors of two; doses above 200 mg have not been studied. ( 2.1 ) Hepatic Cirrhosis: Initial dose is 5 or 10 mg once daily. Titrate by factors of two; doses above 40 mg have not been studied. ( 2.1 ) Hypertension: The recommended initial dose is 5 mg once daily. After 4 to 6 weeks, increase to 10 mg once daily, if needed.

Contraindications

  • 4 CONTRAINDICATIONS Torsemide is contraindicated in patients with known hypersensitivity to torsemide or to povidone. Torsemide is contraindicated in patients who are anuric. Torsemide is contraindicated in patients with hepatic coma. Hypersensitivity to torsemide or povidone, anuria, and hepatic coma. ( 4 )

Side Effects

  • 6 ADVERSE REACTIONS The following risks are discussed in more detail in others sections: Hypotension and Worsening Renal Function [see Warnings and Precautions (5.1) ] Electrolyte and Metabolic Abnormalities [see Warnings and Precautions (5.2) ] Ototoxicity [see Warnings and Precautions (5.3) ] The most common adverse reaction is excessive urination (6.7%). ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Avet Pharmaceuticals Inc. at 1-866-901-DRUG (3784) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.

Interactions

  • 7 DRUG INTERACTIONS Non-steroidal anti-inflammatory drugs (NSAIDs): Reduced diuretic, natriuretic, and antihypertensive effects; risk of renal impairment. ( 7.1 ) CYP2C9: Concomitant use with CYP2C9 inhibitors can decrease torsemide clearance. Torsemide may affect the efficacy and safety of sensitive CYP2C9 substrates or of substrates with a narrow therapeutic range, such as warfarin or phenytoin. ( 7.2 ) Cholestyramine: Decreased exposure of torsemide. ( 7.3 ) Organic anion drugs: may decrease diuretic activity of torsemide. ( 7.4 ) Lithium: Risk of lithium toxicity ( 7.