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Torsemide

Pronunciation

Pronunciation: TORE-suh-MIDE
Class: Loop diuretic

Trade Names

Demadex
- Tablets 5 mg
- Tablets 10 mg
- Tablets 20 mg
- Tablets 100 mg
- Injection 10 mg/mL

Pharmacology

Inhibits sodium/potassium/chloride carrier system in ascending loop of Henle, resulting in increased urinary excretion of sodium, chloride, and water. Does not significantly alter glomerular filtration rate, renal plasma flow, or acid-base balance.

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Pharmacokinetics

Absorption

Bioavailability of oral torsemide is approximately 80%, T max is 1 h, and AUC is 2.5 to 200 mg; food delays the time by approximately 30 min, but there is no effect on bioavailability.

Distribution

Torsemide is more than 99% protein bound. Vd is 12 to 15 L in healthy adults or mild to moderate renal function impairment or CHF; Vd is doubled in hepatic cirrhosis.

Metabolism

The major metabolite is a carboxylic acid derivative and is biologically inactive.

Elimination

Torsemide is cleared by hepatic metabolism (about 80%) and about 20% is excreted into urine. Torsemide t ½ is 3.5 h in healthy adults.

Special Populations

Renal Function Impairment

Renal clearance is decreased, but total plasma clearance is not significantly altered. A diuretic response in renal failure may still be achieved if patients are given higher doses.

Hepatic Function Impairment

In patients with hepatic cirrhosis, the Vd, plasma t ½ , and renal clearance are all increased, but total clearance is not changed.

Elderly

There may be a decrease in renal clearance related to the decline in renal function that commonly occurs with aging.

Decompensated CHF

With oral torsemide, in decompensated CHF, hepatic and renal clearances are decreased.

Indications and Usage

Management of edema associated with CHF, hepatic cirrhosis, and renal disease; treatment of hypertension.

Contraindications

Hypersensitivity to sulfonylureas; anuria; severe electrolyte depletion.

Dosage and Administration

Adults

PO/IV 5 to 20 mg once daily. Titrate dose upward until desired response is obtained. Single doses greater than 200 mg have not been studied.

Storage/Stability

Store in dry area away from sunlight.

Drug Interactions

Aminoglycosides

May increase ototoxicity.

Anticoagulants

May enhance anticoagulant activity.

Cisplatin

May cause additive ototoxicity.

Digitalis glycosides

Electrolyte disturbances may predispose to digitalis-induced arrhythmias.

Lithium

May increase plasma lithium levels and toxicity.

Nondepolarizing muscle relaxants

May antagonize or potentiate response to muscle relaxants.

NSAIDs

May decrease effects of torsemide.

Probenecid

May reduce action of torsemide.

Salicylates

May impair diuretic response in patients with cirrhosis and ascites.

Sulfonylureas

May decrease glucose tolerance, resulting in need for increased sulfonylurea dose.

Thiazide diuretics

May cause synergistic effects that may result in profound diuresis and serious electrolyte abnormalities.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

ECG abnormality; chest pain; atrial fibrillation; orthostatic hypotension; ventricular tachycardia; shunt thrombosis.

CNS

Headache; dizziness; asthenia; insomnia; nervousness; syncope.

Dermatologic

Rash; pruritus.

EENT

Hearing loss; sore throat.

GI

Diarrhea; constipation; nausea; dyspepsia; GI hemorrhage; rectal bleeding.

Genitourinary

Excessive urination.

Metabolic

Hyperglycemia; hyperuricemia; hypomagnesemia; hypokalemia; hypocalcemia; hyponatremia; hypochloremia; hypovolemia.

Respiratory

Rhinitis; cough increase.

Miscellaneous

Arthralgia; myalgia.

Precautions

Pregnancy

Category B .

Lactation

Unknown.

Children

Safety and efficacy not established.

Hypersensitivity

Patients with known sulfonamide sensitivity may show allergic reactions to torsemide.

Photosensitivity

Photosensitization may occur.

Hepatic cirrhosis and ascites

Sudden alterations of electrolyte balance may precipitate hepatic encephalopathy and coma.

Hyperuricemia

Asymptomatic hyperuricemia or gout may occur.

Lipids

Increases in LDL, total cholesterol, and triglycerides with decreases in HDL cholesterol may occur.

Ototoxicity

Associated with rapid injection or very large doses.

Overdosage

Symptoms

Dehydration, arrhythmias, decreased renal function, blood volume and electrolyte depletion, weakness, dizziness, mental confusion, anorexia, lethargy, vomiting, cramps, circulatory collapse, vascular thrombosis and embolism.

Patient Information

  • Instruct patient to inform health care provider of all otc or prescription drugs being taken, especially NSAIDs, digitalis, or lithium.
  • Advise hypertensive patient to avoid foods or medications that may increase BP, including otc drugs for appetite suppression or cold symptoms, otc drugs to help keep awake, and excessive consumption of coffee or other substances containing caffeine.
  • Instruct patient to eat potassium-rich foods daily. These foods include banana, cantaloupe, and potatoes.
  • Advise patient not to store drug in bathroom, but in a cool, dry place.
  • Inform patient that drug may raise blood sugar levels. Instruct diabetic patients to monitor blood glucose regularly and report patterns of hyperglycemia.
  • Advise patient that this drug increases urination. Advise patient to take medication early in morning to avoid disrupted sleep.
  • Caution patient to notify health care provider immediately if vomiting and diarrhea occur or if signs of excessive potassium loss (eg, cramps, muscle weakness, nausea, dizziness) are noted.
  • Instruct patient to report these symptoms to health care provider: chest pain, dizziness, rapid heart beat, headache, nausea, increased swelling of feet, black stools, rectal bleeding, rash, face rash, fatigue, or hearing loss.
  • Caution patient to avoid sudden position changes to prevent dizziness or fainting.
  • Advise patient that drug may cause dizziness and to use caution while driving or performing other tasks requiring mental alertness.
  • Caution patient to avoid exposure to sunlight and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.

Copyright © 2009 Wolters Kluwer Health.

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