Side Effects of Demadex (torsemide)

Demadex (torsemide) is a “loop” diuretic (water pill) used to treat edema (water retention) due to congestive heart failure, kidney disease, chronic kidney failure, or liver disease. Demadex also is used alone or combined with other antihypertensive medications to treat high blood pressure (hypertension). 

Demadex causes a profound increase in urine output (diuresis) by preventing the kidney from retaining water. It blocks the reabsorption back into the blood of sodium and water that has been filtered out of the blood by the kidneys. 

The potent diuretic effect of Demadex can cause the loss of large amounts of body water leading to dehydration as well as the loss of electrolytes (for example, sodium, potassium, magnesium, and calcium). Careful medical supervision is necessary during treatment.

Common side effects of Demadex include:

• headache,
• excessive urination,
• dizziness,
• runny nose,
• weakness,
• diarrhea,
• ECG abnormality,
• cough,
• constipation,
• nausea,
• joint pain,
• stomach upset,
• sore throat,
• muscle pain,
• insomnia,
• fluid retention (edema), and
• nervousness.

Serious side effects of Demadex include:

• atrial fibrillation,
• chest pain,
• gastrointestinal bleeding,
• high blood sugar (hyperglycemia),
• increased uric acid,
• low blood potassium (hypokalemia),
• low blood pressure (hypotension),
• dehydration (symptoms include dry mouth, thirst, weakness, drowsiness, reduced kidney function, heart arrhythmias, muscle aches and pains, nausea, vomiting),
• blood clot in shunt,
• rectal bleeding,
• fainting,
• fast heart rate,
• serious skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis),
• allergic reactions,
• pancreatitis,
• reduced number of white blood cells and platelets, and
• ringing in the ears (tinnitus) and reversible hearing loss.

Drug interactions of Demadex include digoxin, which when taken with Demadex can increase the risk of toxicity from digoxin. 

Combining Demadex with other diuretics can exaggerate the losses of potassium and magnesium. 

The body’s ability to eliminate lithium may decrease when taken with Demadex. 

Indomethacin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the diuretic and blood pressure-lowering effects of other loop diuretics and probably can do the same with Demadex. 

Use of Demadex and aminoglycosides may increase the risk of hearing impairment. 

Probenecid decreases the diuretic effect of Demadex by reducing secretion of torsemide into the kidney tubules. 

The safety of Demadex in pregnant women has not been established. It is unknown if Demadex is excreted in human milk. Consult your doctor before breastfeeding. 

Potent medication like torsemide can cause low blood levels of potassium, magnesium, sodium, and calcium. Additionally, fluid losses may lead to dehydration. The symptoms of dehydration may include:

• Dry mouth
• Thirst
• Weakness
• Drowsiness
• Reduced kidney function
• Heart arrhythmias
• Muscle aches and pains
• Nausea
• Vomiting

Possible side effects of this medication reported often include:

• Headache
• Excessive urination
• Dizziness
• Runny nose
• Asthenia
• Diarrhea
• ECG abnormality
• Cough
• Constipation
• Nausea
• Joint pain
• Stomach upset
• Sore throat
• Muscle pain
• Insomnia
• Edema
• Nervousness

Possible serious side effects and adverse effects include:

• Atrial fibrillation
• Chest pain
• Gastrointestinal bleeding
• High blood sugar (hyperglycemia)
• Increased uric acid (hyperuricemia)
• Low blood potassium (hypokalemia)
• Low blood pressure (hypotension)
• Dehydration (symptoms listed previously)
• Shunt thrombosis
• Rectal bleeding
• Fainting
• Ventricular tachycardia
• Serious skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis)
• Allergic reactions
• Pancreatitis
• Reduced number of white blood cells and platelets

Ringing in the ears (tinnitus) and reversible hearing loss may occur.

Demadex can cause dehydration and loss of potassium and other electrolytes. Low potassium levels (hypokalemia) can cause abnormal heartbeats especially in people with heart disease or those taking the medicine digoxin (Lanoxin). Levels of potassium and other electrolytes should be monitored during medical treatment with this medicine.

The following risks are discussed in more detail in others sections:

• Hypotension and Worsening Renal Function
• Electrolyte and Metabolic Abnormalities
• Ototoxicity

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In pre-approval studies, Demadex has been evaluated for safety in approximately 4000 subjects; over 800 of these subjects received Demadex for at least 6 months, and over 380 were treated for more than 1 year. Among these subjects were 564 who received Demadex during United States-based trials in which 274 other subjects received placebo.

Discontinuation of therapy due to adverse reactions occurred in 3.5% of United States patients treated with Demadex and in 4.4% of patients treated with placebo.

In United States placebo-controlled trials excessive urination occurred in 6.7% of patients compared with 2.2% of patients receiving placebo. The daily doses of Demadex used in these trials ranged from 1.25 mg to 20 mg, with most patients receiving 5 mg to 10 mg; the duration of treatment ranged from 1 to 52 days, with a median of 41 days.

In the placebo-controlled hypertension studies excessive urination was dose related; 1% of patients receiving placebo, 4% of those treated with 5 mg of daily Demadex, and 15% of those treated with 10 mg. Excessive urination was generally not reported as an adverse event among patients who received Demadex for cardiac, renal, or hepatic failure.

There was no effect of age or sex on the incidence of adverse reactions.

Laboratory Parameters

Potassium

In controlled studies in the United States, Demadex was administered to hypertensive patients at doses of 5 mg or 10 mg daily. After 6 weeks at these doses, the mean decrease in serum potassium was approximately 0.1 mEq/L. The percentage of patients who had a serum potassium level below 3.5 mEq/L at any time during the studies was 1.5% on Demadex and 3% on placebo.

In patients followed for 1 year, there was no progressive change in mean serum potassium levels. In patients with congestive heart failure, hepatic cirrhosis, or renal disease treated with Demadex at doses higher than those studied in United States antihypertensive trials, hypokalemia was observed with greater frequency, in a dose-related manner.

Blood Urea Nitrogen (BUN), Creatinine and Uric Acid

Demadex produces small dose-related increases in each of these laboratory values. In hypertensive patients who received 10 mg of Demadex daily for 6 weeks, the mean increase in blood urea nitrogen was 1.8 mg/dL (0.6 mmol/L), the mean increase in serum creatinine was 0.05 mg/dL (4 mmol/L), and the mean increase in serum uric acid was 1.2 mg/dL (70 mmol/L). Little further change occurred with long-term treatment, and all changes reversed when treatment was discontinued.

Glucose

Hypertensive patients who received 10 mg of daily Demadex experienced a mean increase in serum glucose concentration of 5.5 mg/dL (0.3 mmol/L) after 6 weeks of therapy, with a further increase of 1.8 mg/dL (0.1 mmol/L) during the subsequent year. In long-term studies in diabetics, mean fasting glucose values were not significantly changed from baseline.

Serum Lipids

Demadex 20 mg caused small increases in total cholesterol and triglycerides in short term hypertension studies. The changes subsided with chronic therapy.

Postmarketing Experience

The following adverse reactions have been identified during the post-approval use of Demadex. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or establish a causal relationship to drug exposure.

Gastrointestinal system: Pancreatitis, abdominal pain

Nervous System: Paresthesia, confusion, visual impairment, loss of appetite

Hematologic: Leucopenia, thrombocytopenia, anemia

Hepatobiliary: Increase in liver transaminases, gamma-glutamyltransferase

Metabolism: Thiamine (vitamin B1) deficiency

Skin/hypersensitivity: Stevens-Johnson syndrome, toxic epidermal necrolysis, photosensitivity reaction, pruritus

Urogenital: Acute urinary retention

Nonsteroidal Anti-Inflammatory Drugs

Because Demadex and salicylates compete for secretion by renal tubules, patients receiving high doses of salicylates may experience salicylate toxicity when Demadex is concomitantly administered.

Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) and torsemide has been associated with the development of acute renal failure. The antihypertensive and diuretic effects of Demadex can be reduced by NSAIDs.

Partial inhibition of the natriuretic effect of Demadex by concomitant administration of indomethacin has been demonstrated for Demadex under conditions of dietary sodium restriction (50 mEq/day) but not in the presence of normal sodium intake (150 mEq/day).

Cytochrome P450 2C9 Inhibitors And Inducers

Torsemide is a substrate of CYP2C9. Concomitant use of CYP2C9 inhibitors (e.g., amiodarone, fluconazole, miconazole, oxandrolone) can decrease torsemide clearance and increase torsemide plasma concentrations. Concomitant use of CYP2C9 inducers (e.g., rifampin) increase torsemide clearance and decrease plasma torsemide concentrations. Monitor diuretic effect and blood pressure when used in combination with CYP2C9 inhibitor or inducer. Adjust torsemide dose if necessary.

Because of its inhibition of CYP2C9 metabolism, torsemide may affect the efficacy and safety of sensitive CYP2C9 substrates, such as celecoxib, or of substrates with a narrow therapeutic range, such as warfarin or phenytoin. Monitor patients and adjust dosages if necessary.

Cholestyramine

Concomitant use of torsemide and cholestyramine has not been studied in humans but, in a study in animals, coadministration of cholestyramine decreased the absorption of orally administered torsemide. If Demadex and cholestyramine should be coadministered, administer Demadex at least one hour before or 4 to 6 h after cholestyramine administration.

Organic Anion Drugs

Coadministration of organic anion drugs (e.g., probenecid) that undergo significant renal tubular secretion have the potential to reduce secretion of Demadex into the proximal tubule and thereby decreases the diuretic activity of Demadex. Monitor diuretic effect and blood pressure during coadministration.

Lithium

Like other diuretics, torsemide reduces the renal clearance of lithium, inducing a high risk of lithium toxicity. Monitor lithium levels periodically when torsemide is coadministered.

Ototoxic Drugs

Loop diuretics increase the ototoxic potential of other ototoxic drugs, including aminoglycoside antibiotics and ethacrynic acid. This effect has been reported with concomitant use of torsemide and gentamycin. Avoid concomitant use of Demadex and aminoglycoside antibiotics, if possible.

Renin-angiotensin Inhibitors

Coadministration of Demadex with ACE inhibitors or angiotensin receptor blockers can increase the risk of hypotension and renal impairment.

Radiocontrast Agents

Demadex can increase the risk of renal toxicity related to administration of radiocontrast agents.

Corticosteroids And ACTH

Concomitant use with Demadex may increase risk of hypokalemia