torsemide

Absorption: 80% absorbed after oral administration.

Distribution: Widely distributed to tissues.

Protein Binding: ≥99%.

Metabolism/Excretion: Primarily metabolized by the liver via the CYP2C9 isoenzyme, with minor metabolism via the CYP2C8 and CYP2C18 isoenzymes. 80% metabolized by liver, 20% excreted in urine.

Half-Life: 3.5 hr.

Time/Action Profile ⬆ ⬇

(diuretic effect)

ROUTE	ONSET	PEAK	DURATION
PO	within 60 min	60–120 min	6–8 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Cross-sensitivity with thiazide diuretics and sulfonamides may occur;
Hepatic coma;
Anuria.

Use Cautiously in:

Severe hepatic impairment (may precipitate hepatic coma; concurrent use with potassium-sparing diuretics may be necessary);
Electrolyte depletion;
Severe renal impairment and hypoproteinemia (↑ risk of ototoxicity);
Diabetes mellitus;
Increasing azotemia;
OB: Safety not established in pregnancy;
Lactation: Safety not established in breastfeeding;
Pedi: Safety and effectiveness not established in children;
Geri: Older adults may have risk of side effects, especially hypotension and electrolyte imbalance, at usual doses.

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypotension

Derm: photosensitivity, rash, STEVENS-JOHNSON SYNDROME (SJS), TOXIC EPIDERMAL NECROLYSIS (TEN)

EENT: hearing loss, tinnitus

Endo: hyperglycemia

F and E: dehydration, hypochloremia, hypokalemia, hypomagnesemia, hyponatremia, hypovolemia, metabolic alkalosis, hypocalcemia

GI: constipation, diarrhea, dry mouth, dyspepsia, nausea, vomiting

GU: acute renal failure, excessive urination, renal impairment

Metab: hyperuricemia

MS: arthralgia, muscle cramps, myalgia

Neuro: dizziness, headache, nervousness

Interactions ⬆ ⬇

Drug-drug:

↑hypotension with antihypertensives, nitrates, or acute ingestion of alcohol.
↑risk of hypokalemia with other diuretics, amphotericin B, stimulant laxatives, and corticosteroids.
Hypokalemia may ↑ risk of digoxin toxicity and ↑ risk of arrhythmia in patients taking drugs that prolong the QT interval.
CYP2C9 inhibitors, including amiodarone, fluconazole, and miconazole, may ↑ levels and the risk of toxicity.
CYP2C9 inducers, including rifampin, may ↓ levels and effectiveness.
May ↑ levels and the risk of toxicity of CYP2C9 substrates, including celecoxib, phenytoin, or warfarin.
↑risk of nephrotoxicity with other nephrotoxic drugs, including aminoglycosides, cisplatin, NSAIDs, ACE inhibitors, angiotensin II receptor blockers, and radiocontrast agents.
May ↑ the risk of lithium toxicity.
↑risk of ototoxicity with aminoglycosides.
NSAIDs may ↓ effectiveness.
May ↑ the risk of salicylate toxicity (with use of high-dose salicylate therapy).
Cholestyramine may ↓ absorption.

Route/Dosage ⬆ ⬇

Heart Failure

PO (Adults ): Generic or Soaanz: 20 mg once daily; dose may be doubled until desired effect is obtained (max = 200 mg/day).

Chronic Renal Failure

PO (Adults ): Generic or Soaanz: 20 mg once daily; dose may be doubled until desired effect is obtained (max = 200 mg/day).

Hepatic Cirrhosis

PO (Adults ): Generic only: 5–10 mg once daily (with aldosterone antagonist or potassium-sparing diuretic); dose may be doubled until desired effect is obtained (max = 40 mg/day).

Hypertension

PO (Adults ): Generic only: 2.5–5 mg once daily, may be ↑ to 10 mg once daily after 4–6 wk (if still not effective, add another agent).

Availability ⬆ ⬇

(Generic available)

Tablets: 5 mg; 10 mg; 20 mg; 40 mg; 60 mg; 100 mg

Assessment ⬆ ⬇

Assess fluid status during therapy. Monitor daily weight, intake and output ratios, amount and location of edema, lung sounds, skin turgor, and mucous membranes. Notify health care professional if thirst, dry mouth, lethargy, weakness, hypotension, or oliguria occurs.
Monitor BP and pulse before and during administration. Monitor frequency of prescription refills to determine adherence in patients treated for hypertension.
Assess patients receiving digoxin for anorexia, nausea, vomiting, muscle cramps, paresthesia, and confusion. Patients taking digoxin are at increased risk of digoxin toxicity due to potassium-depleting effect of the diuretic. Potassium supplements or potassium-sparing diuretics may be used concurrently to prevent hypokalemia.
Assess patient for tinnitus and hearing loss. Audiometry is recommended for patients receiving prolonged high-dose IV therapy. Hearing loss is most common following rapid or high-dose IV administration in patients with decreased renal function or those taking other ototoxic drugs.
Assess for allergy to sulfonamides.
Assess patient for skin rash frequently during therapy. Discontinue torsemide at first sign of rash; may be life-threatening. SJS or TEN may develop. Treat symptomatically; may recur once treatment is stopped.
Geri: Diuretic use is associated with increased risk for falls in older adults. Assess falls risk and implement fall prevention strategies.

Lab Test Considerations:

Monitor electrolytes, renal and hepatic function, serum glucose, and uric acid levels before and periodically during therapy. May cause ↓ serum sodium, potassium, calcium, and magnesium concentrations. May also cause ↑ BUN, serum glucose, serum creatinine, and uric acid levels.

Implementation ⬆ ⬇

Administer medication in the morning to prevent disruption of sleep cycle.
PO: May be taken with food or milk to minimize gastric irritation.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take torsemide as directed. Take missed doses as soon as possible; do not double doses.
- Caution patient to change positions slowly to minimize orthostatic hypotension. Caution patient that the use of alcohol, exercise during hot weather, or standing for long periods during therapy may enhance orthostatic hypotension.
- Instruct patient to consult health care professional regarding a diet high in potassium (see Food Sources for Specific Nutrients).
- Advise patient to contact health care professional if they gain more than 2–3 lb/day.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking any OTC medications concurrently with this therapy.
- Instruct patient to notify health care professional of medication regimen prior to treatment or surgery.
- Caution patient to use sunscreen and protective clothing to prevent photosensitivity reactions.
- Advise patient to contact health care professional immediately if rash muscle weakness, cramps, nausea, dizziness, numbness, or tingling of extremities occurs.
- Advise diabetic patients to monitor blood glucose closely; may cause increased blood glucose levels.
- Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
- Emphasize the importance of routine follow-up examinations.
Hypertension: Advise patients on antihypertensive regimen to continue taking medication even if feeling better. Torsemide controls but does not cure hypertension.
- Reinforce the need to continue additional therapies for hypertension (weight loss, exercise, restricted sodium intake, stress reduction, regular exercise, moderation of alcohol consumption, cessation of smoking).

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇