Demadex
DEMADEX®
(torsemide) Tablets & Injection
DRUG DESCRIPTION
DEMADEX (torsemide) is a diuretic of the pyridine-sulfonylurea class. Its chemical name is 1-isopropyl-3-[(4-m-toluidino-3-pyridyl) sulfonylurea and its structural formula is:
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Its empirical formula is C16H20N4O3S, its pKa is 7.1, and its molecular weight is 348.43.
Torsemide is a white to off-white crystalline powder. The tablets for oral administration also contain lactose NF, crospovidone NF, povidone USP, microcrystalline cellulose NF, and magnesium stearate NF. Torsemide ampuls for intravenous injection contain a sterile solution of torsemide (10 mg/mL), polyethylene glycol-400 NF, tromethamine USP, and sodium hydroxide NF (as needed to adjust pH) in water for injection USP.
Last updated on RxList: 5/28/2008
INDICATIONS
DEMADEX is indicated for the treatment of edema associated with congestive heart failure, renal disease, or hepatic disease. Use of torsemide has been found to be effective for the treatment of edema associated with chronic renal failure. Chronic use of any diuretic in hepatic disease has not been studied in adequate and well-controlled trials.
DEMADEX intravenous injection is indicated when a rapid onset of diuresis is desired or when oral administration is impractical.
DEMADEX is indicated for the treatment of hypertension alone or in combination with other antihypertensive agents.
DOSAGE AND ADMINISTRATION
General
DEMADEX tablets may be given at any time in relation to a meal, as convenient. Special dosage adjustment in the elderly is not necessary.
Because of the high bioavailability of DEMADEX, oral and intravenous doses are therapeutically equivalent, so patients may be switched to and from the intravenous form with no change in dose. DEMADEX intravenous injection should be administered either slowly as a bolus over a period of 2 minutes or administered as a continuous infusion.
If DEMADEX is administered through an IV line, it is recommended that, as with other IV injections, the IV line be flushed with Normal Saline (Sodium Chloride Injection, USP) before and after administration. DEMADEX injection is formulated above pH 8.3. Flushing the line is recommended to avoid the potential for incompatibilities caused by differences in pH which could be indicated by color change, haziness or the formation of a precipitate in the solution.
If DEMADEX is administered as a continuous infusion, stability has been demonstrated through 24 hours at room temperature in plastic containers for the following fluids and concentrations:
200 mg DEMADEX (10 mg/mL) added to:
250 mL Dextrose 5% in water
250 mL 0.9% Sodium Chloride
500 mL 0.45% Sodium Chloride
50 mg DEMADEX (10 mg/mL) added to:
500 mL Dextrose 5% in water
500 mL 0.9% Sodium Chloride
500 mL 0.45% Sodium Chloride
Before administration, the solution of DEMADEX should be visually inspected for discoloration and particulate matter. If either is found, the ampul should not be used.
Congestive Heart Failure
The usual initial dose is 10 mg or 20 mg of once-daily oral or intravenous DEMADEX. If the diuretic response is inadequate, the dose should be titrated upward by approximately doubling until the desired diuretic response is obtained. Single doses higher than 200 mg have not been adequately studied.
Chronic Renal Failure
The usual initial dose of DEMADEX is 20 mg of once-daily oral or intravenous DEMADEX. If the diuretic response is inadequate, the dose should be titrated upward by approximately doubling until the desired diuretic response is obtained. Single doses higher than 200 mg have not been adequately studied.
Hepatic Cirrhosis
The usual initial dose is 5 mg or 10 mg of once-daily oral or intravenous DEMADEX, administered together with an aldosterone antagonist or a potassium-sparing diuretic. If the diuretic response is inadequate, the dose should be titrated upward by approximately doubling until the desired diuretic response is obtained. Single doses higher than 40 mg have not been adequately studied.
Chronic use of any diuretic in hepatic disease has not been studied in adequate and well-controlled trials.
Hypertension
The usual initial dose is 5 mg once daily. If the 5 mg dose does not provide adequate reduction in blood pressure within 4 to 6 weeks, the dose may be increased to 10 mg once daily. If the response to 10 mg is insufficient, an additional antihypertensive agent should be added to the treatment regimen.
HOW SUPPLIED
DEMADEX for oral administration is available as white, scored tablets containing 5 mg, 10 mg, 20 mg, or 100 mg of torsemide. The tablets are supplied in bottles and Tel-E-Dose * packages of 100 as follows:
| Dose | Shape | Bottle | Tel-E-Dose |
| 5 mg | elliptical | NDC 0004-0262-01 | NDC 0004-0262-49 |
| 10 mg | elliptical | NDC 0004-0263-01 | NDC 0004-0263-49 |
| 20 mg | elliptical | NDC 0004-0264-01 | NDC 0004-0264-49 |
| 100 mg | capsule shaped | NDC 0004-0265-01 | NDC 0004-0265-49 |
Each tablet is debossed on the scored side with the logo BM and 102, 103, 104, or 105 (for 5 mg, 10 mg, 20 mg, or 100 mg, respectively). On the opposite side, the tablet is debossed with 5, 10, 20, or 100 to indicate the dose.
DEMADEX for intravenous injection is supplied in clear ampuls containing 2 mL (20 mg, NDC 0004-0267-06) or 5 mL (50 mg, NDC 0004-0268-06) of a 10 mg/mL sterile solution. The ampuls are supplied in boxes of 10.
Storage
Store all dosage forms at 15° to 30°C (59° to 86°F). Do not freeze.
*Tel-E-Dose is a registered trademark of Hoffmann-La Roche Inc.
Distributed by: Laboratories Inc. 340 Kingsland Street, Nutley, New Jersey 07110-1199. Revised: April 2003. FDA Rev date: 9/17/2002
Last updated on RxList: 5/28/2008
SIDE EFFECTS
At the time of approval, DEMADEX had 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.
The reported side effects of DEMADEX were generally transient, and there was no relationship between side effects and age, sex, race, or duration of therapy. Discontinuation of therapy due to side effects occurred in 3.5% of United States patients treated with DEMADEX and in 4.4% of patients treated with placebo. In studies conducted in the United States and Europe, discontinuation rates due to side effects were 3.0% (38/1250) with DEMADEX and 3.4% (13/380) with furosemide in patients with congestive heart failure, 2.0% (8/409) with DEMADEX and 4.8% (11/230) with furosemide in patients with renal insufficiency, and 7.6% (13/170) with DEMADEX and 0% (0/33) with furosemide in patients with cirrhosis.
The most common reasons for discontinuation of therapy with DEMADEX were (in descending order of frequency) dizziness, headache, nausea, weakness, vomiting, hyperglycemia, excessive urination, hyperuricemia, hypokalemia, excessive thirst, hypovolemia, impotence, esophageal hemorrhage, and dyspepsia. Dropout rates for these adverse events ranged from 0.1% to 0.5%.
The side effects considered possibly or probably related to study drug that occurred in United States placebo-controlled trials in more than 1% of patients treated with DEMADEX are shown in Table 1.
Table 1: Reactions Possibly or Probably Drug-Related United
States Placebo-Controlled Studies Incidence (Percentages of Patients)
| DEMADEX (N=564) |
Placebo (N=274) |
|
| Headache | 7.3 | 9.1 |
| Excessive Urination | 6.7 | 2.2 |
| Dizziness | 3.2 | 4.0 |
| Rhinitis | 2.8 | 2.2 |
| Asthenia | 2.0 | 1.5 |
| Diarrhea | 2.0 | 1.1 |
| ECG Abnormality | 2.0 | 0.4 |
| Cough Increase | 2.0 | 1.5 |
| Constipation | 1.8 | 0.7 |
| Nausea | 1.8 | 0.4 |
| Arthralgia | 1.8 | 0.7 |
| Dyspepsia | 1.6 | 0.7 |
| Sore Throat | 1.6 | 0.7 |
| Myalgia | 1.6 | 1.5 |
| Chest Pain | 1.2 | 0.4 |
| Insomnia | 1.2 | 1.8 |
| Edema | 1.1 | 1.1 |
| Nervousness | 1.1 | 0.4 |
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. Of the side effects listed in the table, only "excessive urination" occurred significantly more frequently in patients treated with DEMADEX than in patients treated with placebo. In the placebo-controlled hypertension studies whose design allowed side-effect rates to be attributed to dose, excessive urination was reported by 1% of patients receiving placebo, 4% of those treated with 5 mg of daily DEMADEX, and 15% of those treated with 10 mg. The complaint of excessive urination was generally not reported as an adverse event among patients who received DEMADEX for cardiac, renal, or hepatic failure.
Serious adverse events reported in the clinical studies for which a drug relationship could not be excluded were atrial fibrillation, chest pain, diarrhea, digitalis intoxication, gastrointestinal hemorrhage, hyperglycemia, hyperuricemia, hypokalemia, hypotension, hypovolemia, shunt thrombosis, rash, rectal bleeding, syncope, and ventricular tachycardia.
Angioedema has been reported in a patient exposed to DEMADEX who was later found to be allergic to sulfa drugs.
Of the adverse reactions during placebo-controlled trials listed without taking into account assessment of relatedness to drug therapy, arthritis and various other nonspecific musculoskeletal problems were more frequently reported in association with DEMADEX than with placebo, even though gout was somewhat more frequently associated with placebo. These reactions did not increase in frequency or severity with the dose of DEMADEX. One patient in the group treated with DEMADEX withdrew due to myalgia, and one in the placebo group withdrew due to gout.
Hypokalemia: See WARNINGS.
DRUG INTERACTIONS
In patients with essential hypertension, DEMADEX has been administered together with beta-blockers, ACE inhibitors, and calcium-channel blockers. In patients with congestive heart failure, DEMADEX has been administered together with digitalis glycosides, ACE inhibitors, and organic nitrates. None of these combined uses was associated with new or unexpected adverse events.
Torsemide does not affect the protein binding of glyburide or of warfarin, the anticoagulant effect of phenprocoumon (a related coumarin derivative), or the pharmacokinetics of digoxin or carvedilol (a vasodilator/beta-blocker). In healthy subjects, coadministration of DEMADEX was associated with significant reduction in the renal clearance of spironolactone, with corresponding increases in the AUC. However, clinical experience indicates that dosage adjustment of either agent is not required.
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. Also, although possible interactions between torsemide and nonsteroidal anti-inflammatory agents (including aspirin) have not been studied, coadministration of these agents with another loop diuretic (furosemide) has occasionally been associated with renal dysfunction.
The natriuretic effect of DEMADEX (like that of many other diuretics) is partially inhibited by the concomitant administration of indomethacin. This effect 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).
The pharmacokinetic profile and diuretic activity of torsemide are not altered by cimetidine or spironolactone. Coadministration of digoxin is reported to increase the area under the curve for torsemide by 50%, but dose adjustment of DEMADEX is not necessary.
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 are used concomitantly, simultaneous administration is not recommended.
Coadministration of probenecid reduces secretion of DEMADEX into the proximal tubule and thereby decreases the diuretic activity of DEMADEX.
Other diuretics are known to reduce the renal clearance of lithium, inducing a high risk of lithium toxicity, so coadministration of lithium and diuretics should be undertaken with great caution, if at all. Coadministration of lithium and DEMADEX has not been studied.
Other diuretics have been reported to increase the ototoxic potential of aminoglycoside antibiotics and of ethacrynic acid, especially in the presence of impaired renal function. These potential interactions with DEMADEX have not been studied.
Last updated on RxList: 5/28/2008
WARNINGS
Hepatic Disease With Cirrhosis and Ascites
DEMADEX should be used with caution in patients with hepatic disease with cirrhosis and ascites, since sudden alterations of fluid and electrolyte balance may precipitate hepatic coma. In these patients, diuresis with DEMADEX (or any other diuretic) is best initiated in the hospital. To prevent hypokalemia and metabolic alkalosis, an aldosterone antagonist or potassium-sparing drug should be used concomitantly with DEMADEX.
Ototoxicity
Tinnitus and hearing loss (usually reversible) have been observed after rapid intravenous injection of other loop diuretics and have also been observed after oral DEMADEX. It is not certain that these events were attributable to DEMADEX. Ototoxicity has also been seen in animal studies when very high plasma levels of torsemide were induced. Administered intravenously, DEMADEX should be injected slowly over 2 minutes, and single doses should not exceed 200 mg.
Volume and Electrolyte Depletion
Patients receiving diuretics should be observed for clinical evidence of electrolyte imbalance, hypovolemia, or prerenal azotemia. Symptoms of these disturbances may include one or more of the following: dryness of the mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, nausea, and vomiting. Excessive diuresis may cause dehydration, blood-volume reduction, and possibly thrombosis and embolism, especially in elderly patients. In patients who develop fluid and electrolyte imbalances, hypovolemia, or prerenal azotemia, the observed laboratory changes may include hyper- or hyponatremia, hyper- or hypochloremia, hyper- or hypokalemia, acid-base abnormalities, and increased blood urea nitrogen (BUN). If any of these occur, DEMADEX should be discontinued until the situation is corrected; DEMADEX may be restarted at a lower dose.
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 essentially the same in patients who received DEMADEX (1.5%) as in those who received placebo (3%). In patients followed for 1 year, there was no further 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.
In patients with cardiovascular disease, especially those receiving digitalis glycosides, diuretic-induced hypokalemia may be a risk factor for the development of arrhythmias. The risk of hypokalemia is greatest in patients with cirrhosis of the liver, in patients experiencing a brisk diuresis, in patients who are receiving inadequate oral intake of electrolytes, and in patients receiving concomitant therapy with corticosteroids or ACTH.
Periodic monitoring of serum potassium and other electrolytes is advised in patients treated with DEMADEX.
PRECAUTIONS
Laboratory Values
Potassium: See WARNINGS.
Calcium
Single doses of DEMADEX increased the urinary excretion of calcium by normal subjects, but serum calcium levels were slightly increased in 4- to 6- week hypertension trials. In a long-term study of patients with congestive heart failure, the average 1-year change in serum calcium was a decrease of 0.10 mg/dL (0.02 mmol/L). Among 426 patients treated with DEMADEX for an average of 11 months, hypocalcemia was not reported as an adverse event.
Magnesium
Single doses of DEMADEX caused healthy volunteers to increase their urinary excretion of magnesium, but serum magnesium levels were slightly increased in 4- to 6-week hypertension trials. In long-term hypertension studies, the average 1-year change in serum magnesium was an increase of 0.03 mg/dL (0.01 mmol/L). Among 426 patients treated with DEMADEX for an average of 11 months, one case of hypomagnesemia (1.3 mg/dL [0.53 mmol/L]) was reported as an adverse event.
In a long-term clinical study of DEMADEX in patients with congestive heart failure, the estimated annual change in serum magnesium was an increase of 0.2 mg/dL (0.08 mmol/L), but these data are confounded by the fact that many of these patients received magnesium supplements. In a 4-week study in which magnesium supplementation was not given, the rate of occurrence of serum magnesium levels below 1.7 mg/dL (0.70 mmol/L) was 6% and 9% in the groups receiving 5 mg and 10 mg of DEMADEX, respectively.
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.
Symptomatic gout has been reported in patients receiving DEMADEX, but its incidence has been similar to that seen in patients receiving placebo.
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. Cases of hyperglycemia have been reported but are uncommon.
Serum Lipids
In the controlled short-term hypertension studies in the United States, daily doses of 5 mg, 10 mg, and 20 mg of DEMADEX were associated with increases in total plasma cholesterol of 4, 4, and 8 mg/dL (0.10 to 0.20 mmol/L), respectively. The changes subsided during chronic therapy.
In the same short-term hypertension studies, daily doses of 5 mg, 10 mg and 20 mg of DEMADEX were associated with mean increases in plasma triglycerides of 16, 13 and 71 mg/dL (0.15 to 0.80 mmol/L), respectively.
In long-term studies of 5 mg to 20 mg of DEMADEX daily, no clinically significant differences from baseline lipid values were observed after 1 year of therapy.
Other
In long-term studies in hypertensive patients, DEMADEX has been associated with small mean decreases in hemoglobin, hematocrit, and erythrocyte count and small mean increases in white blood cell count, platelet count, and serum alkaline phosphatase. Although statistically significant, all of these changes were medically inconsequential. No significant trends have been observed in any liver enzyme tests other than alkaline phosphatase.
Carcinogenesis, Mutagenesis and Impairment of Fertility
No overall increase in tumor incidence was found when torsemide was given to rats and mice throughout their lives at doses up to 9 mg/kg/day (rats) and 32 mg/kg/day (mice). On a body-weight basis, these doses are 27 to 96 times a human dose of 20 mg; on a body-surface-area basis, they are 5 to 8 times this dose. In the rat study, the high-dose female group demonstrated renal tubular injury, interstitial inflammation, and a statistically significant increase in renal adenomas and carcinomas. The tumor incidence in this group was, however, not much higher than the incidence sometimes seen in historical controls. Similar signs of chronic non-neoplastic renal injury have been reported in high-dose animal studies of other diuretics such as furosemide and hydrochlorothiazide.
No mutagenic activity was detected in any of a variety of in vivo and in vitro tests of torsemide and its major human metabolite. The tests included the Ames test in bacteria (with and without metabolic activation), tests for chromosome aberrations and sister-chromatid exchanges in human lymphocytes, tests for various nuclear anomalies in cells found in hamster and murine bone marrow, tests for unscheduled DNA synthesis in mice and rats, and others.
In doses up to 25 mg/kg/day (75 times a human dose of 20 mg on a body- weight basis; 13 times this dose on a body-surface-area basis), torsemide had no adverse effect on the reproductive performance of male or female rats.
Pregnancy
Pregnancy Category B.
There was no fetotoxicity or teratogenicity in rats treated with up to 5 mg/kg/day of torsemide (on a mg/kg basis, this is 15 times a human dose of 20 mg/day; on a mg/m2 basis, the animal dose is 10 times the human dose), or in rabbits, treated with 1.6 mg/kg/day (on a mg/kg basis, 5 times the human dose of 20 mg/kg/day; on a mg/m2 basis, 1.7 times this dose). Fetal and maternal toxicity (decrease in average body weight, increase in fetal resorption and delayed fetal ossification) occurred in rabbits and rats given doses 4 (rabbits) and 5 (rats) times larger. Adequate and well-controlled studies have not been carried out in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Labor and Delivery
The effect of DEMADEX on labor and delivery is unknown.
Nursing Mothers
It is not known whether DEMADEX is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when DEMADEX is administered to a nursing woman.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established.
Administration of another loop diuretic to severely premature infants with edema due to patent ductus arteriosus and hyaline membrane disease has occasionally been associated with renal calcifications, sometimes barely visible on X-ray but sometimes in staghorn form, filling the renal pelves. Some of these calculi have been dissolved, and hypercalciuria has been reported to have decreased, when chlorothiazide has been coadministered along with the loop diuretic. In other premature neonates with hyaline membrane disease, another loop diuretic has been reported to increase the risk of persistent patent ductus arteriosus, possibly through a prostaglandin-E- mediated process. The use of DEMADEX in such patients has not been studied.
Geriatric Use
Of the total number of patients who received DEMADEX in United States clinical studies, 24% were 65 or older while about 4% were 75 or older. No specific age-related differences in effectiveness or safety were observed between younger patients and elderly patients.
Last updated on RxList: 5/28/2008
OVERDOSE
There is no human experience with overdoses of DEMADEX, but the signs and symptoms of overdosage can be anticipated to be those of excessive pharmacologic effect: dehydration, hypovolemia, hypotension, hyponatremia, hypokalemia, hypochloremic alkalosis, and hemoconcentration. Treatment of overdosage should consist of fluid and electrolyte replacement.
Laboratory determinations of serum levels of torsemide and its metabolites are not widely available.
No data are available to suggest physiological maneuvers (eg, maneuvers to change the pH of the urine) that might accelerate elimination of torsemide and its metabolites. Torsemide is not dialyzable, so hemodialysis will not accelerate elimination.
CONTRAINDICATIONS
DEMADEX is contraindicated in patients with known hypersensitivity to DEMADEX or to sulfonylureas.
DEMADEX is contraindicated in patients who are anuric.
Last updated on RxList: 5/28/2008
CLINICAL PHARMACOLOGY
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+/2CI--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.
Pharmacokinetics and Metabolism
The bioavailability of DEMADEX tablets is approximately 80%, with little intersubject variation; the 90% confidence interval is 75% to 89%. The drug is absorbed with little first-pass metabolism, and the serum concentration reaches its peak (Cmax) within 1 hour after oral administration. Cmax and area under the serum concentration-time curve (AUC) after oral administration are proportional to dose over the range of 2.5 mg to 200 mg. Simultaneous food intake delays the time to Cmax by about 30 minutes, but overall bioavailability (AUC) and diuretic activity are unchanged. Absorption is essentially unaffected by renal or hepatic dysfunction.
The volume of distribution of torsemide is 12 liters to 15 liters in normal adults or in patients with mild to moderate renal failure or congestive heart failure. In patients with hepatic cirrhosis, the volume of distribution is approximately doubled.
In normal subjects the elimination half-life of torsemide is approximately 3.5 hours. Torsemide is cleared from the circulation by both hepatic metabolism (approximately 80% of total clearance) and excretion into the urine (approximately 20% of total clearance in patients with normal renal function). The major metabolite in humans is the carboxylic acid derivative, which is biologically inactive. Two of the lesser metabolites possess some diuretic activity, but for practical purposes metabolism terminates the action of the drug.
Because torsemide is extensively bound to plasma protein ( > 99%), very little enters tubular urine via glomerular filtration. Most renal clearance of torsemide occurs via active secretion of the drug by the proximal tubules into tubular urine.
In patients with decompensated congestive heart failure, hepatic and renal clearance are both reduced, probably because of hepatic congestion and decreased renal plasma flow, respectively. The total clearance of torsemide is approximately 50% of that seen in healthy volunteers, and the plasma half-life and AUC are correspondingly increased. Because of reduced renal clearance, a smaller fraction of any given dose is delivered to the intraluminal site of action, so at any given dose there is less natriuresis in patients with congestive heart failure than in normal subjects.
In patients with renal failure, renal clearance of torsemide is markedly decreased but total plasma clearance is not significantly altered. A smaller fraction of the administered dose is delivered to the intraluminal site of action, and the natriuretic action of any given dose of diuretic is reduced. A diuretic response in renal failure may still be achieved if patients are given higher doses. The total plasma clearance and elimination half-life of torsemide remain normal under the conditions of impaired renal function because metabolic elimination by the liver remains intact.
In patients with hepatic cirrhosis, the volume of distribution, plasma half-life, and renal clearance are all increased, but total clearance is unchanged.
The pharmacokinetic profile of torsemide in healthy elderly subjects is similar to that in young subjects except for a decrease in renal clearance related to the decline in renal function that commonly occurs with aging. However, total plasma clearance and elimination half-life remain unchanged.
Clinical Effects
The diuretic effects of DEMADEX begin within 10 minutes of intravenous dosing and peak within the first hour. With oral dosing, the onset of diuresis occurs within 1 hour and the peak effect occurs during the first or second hour. Independent of the route of administration, diuresis lasts about 6 to 8 hours. In healthy subjects given single doses, the dose-response relationship for sodium excretion is linear over the dose range of 2.5 mg to 20 mg. The increase in potassium excretion is negligible after a single dose of up to 10 mg and only slight (5 mEq to 15 mEq) after a single dose of 20 mg.
Congestive Heart Failure
DEMADEX has been studied in controlled trials in patients with New York Heart Association Class II to Class IV congestive heart failure. Patients who received 10 mg to 20 mg of daily DEMADEX in these studies achieved significantly greater reductions in weight and edema than did patients who received placebo.
Nonanuric Renal Failure
In single-dose studies in patients with nonanuric renal failure, high doses of DEMADEX (20 mg to 200 mg) caused marked increases in water and sodium excretion. In patients with nonanuric renal failure, severe enough to require hemodialysis, chronic treatment with up to 200 mg of daily DEMADEX has not been shown to change steady-state fluid retention. When patients in a study of acute renal failure received total daily doses of 520 mg to 1200 mg of DEMADEX, 19% experienced seizures. Ninety-six patients were treated in this study; 6/32 treated with torsemide experienced seizures, 6/32 treated with comparably high doses of furosemide experienced seizures, and 1/32 treated with placebo experienced a seizure.
Hepatic Cirrhosis
When given with aldosterone antagonists, DEMADEX also caused increases in sodium and fluid excretion in patients with edema or ascites due to hepatic cirrhosis. Urinary sodium excretion rate relative to the urinary excretion rate of DEMADEX is less in cirrhotic patients than in healthy subjects (possibly because of the hyperaldosteronism and resultant sodium retention that are characteristic of portal hypertension and ascites). However, because of the increased renal clearance of DEMADEX in patients with hepatic cirrhosis, these factors tend to balance each other, and the result is an overall natriuretic response that is similar to that seen in healthy subjects. Chronic use of any diuretic in hepatic disease has not been studied in adequate and well- controlled trials.
Essential Hypertension
In patients with essential hypertension, DEMADEX has been shown in controlled studies to lower blood pressure when administered once a day at doses of 5 mg to 10 mg. The antihypertensive effect is near maximal after 4 to 6 weeks of treatment, but it may continue to increase for up to 12 weeks. Systolic and diastolic supine and standing blood pressures are all reduced. There is no significant orthostatic effect, and there is only a minimal peak- trough difference in blood pressure reduction.
The antihypertensive effects of DEMADEX are, like those of other diuretics, on the average greater in black patients (a low-renin population) than in nonblack patients.
When DEMADEX is first administered, daily urinary sodium excretion increases for at least a week. With chronic administration, however, daily sodium loss comes into balance with dietary sodium intake. If the administration of DEMADEX is suddenly stopped, blood pressure returns to pretreatment levels over several days, without overshoot.
DEMADEX has been administered together with P-adrenergic blocking agents, ACE inhibitors, and calcium-channel blockers. Adverse drug interactions have not been observed, and special dosage adjustment has not been necessary.
Last updated on RxList: 5/28/2008
PATIENT INFORMATION
No information provided. Please refer to the WARNINGS and PRECAUTIONS sections.
Last updated on RxList: 5/28/2008
Consumer
IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.
TORSEMIDE - ORAL
(TOR-seh-mide)
COMMON BRAND NAME(S): Demadex
WARNING: This is a very potent medication. Using too much of this drug can lead to serious water and mineral loss. Therefore, it is important that you are closely monitored by your doctor. Tell your doctor immediately if you become very thirsty or confused, or develop muscle cramps/weakness while taking this medication.
USES: Torsemide is a "water pill" (diuretic) that increases the amount of urine you make, which causes your body to get rid of excess water. This drug is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.
This medication also reduces swelling/fluid retention (edema) which can result from conditions such as congestive heart failure, liver disease, or kidney disease. This can help to improve symptoms such as trouble breathing.
HOW TO USE: Take this medication by mouth with or without food, usually once a day, or as directed by your doctor. The dosage is based on your medical condition and response to therapy.
If you take this drug too close to bedtime, you may need to wake up to urinate. Therefore, it is best to take this medication at least 4 hours before your bedtime. Consult your doctor or pharmacist if you have questions about your dosing schedule.
Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day as directed. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick. Generally, it may take 4-6 weeks, sometimes up to 12 weeks, before the full blood pressure-lowering effect is seen. Do not stop taking this medication without consulting your doctor.
Cholestyramine and colestipol can decrease the absorption of torsemide. If you are taking either of these drugs, separate it from torsemide by at least 2 hours.
If your condition persists or worsens, contact your doctor or pharmacist.
SIDE EFFECTS: Dizziness, lightheadedness, headache, blurred vision, loss of appetite, stomach upset, diarrhea, or constipation may occur as your body adjusts to the medication. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may lead to excessive loss of body water and minerals (including potassium). Tell your doctor immediately if you have any of these unlikely but serious symptoms of dehydration or mineral loss: muscle cramps or weakness, confusion, severe dizziness, drowsiness, unusual dry mouth or thirst, nausea or vomiting, fast/irregular heartbeat, unusual decrease in the amount of urine, fainting, seizures.
Tell your doctor immediately if any of these unlikely but serious side effects occur: numbness/tingling of the arms/legs, ringing in the ears, hearing loss, decreased sexual ability.
Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), easy bleeding or bruising, stomach/abdominal pain, persistent nausea/vomiting, yellowing of eyes/skin.
A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching, swelling, severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking torsemide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: severe kidney disease (inability to make urine or anuria).
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, untreated mineral imbalance (e.g., sodium, potassium), gout, lupus.
If you have diabetes, torsemide may infrequently worsen control of blood glucose levels. Monitor your blood glucose levels regularly and inform your doctor of the results.
This drug may reduce the potassium levels in your blood. Ask your doctor about adding potassium to your diet. A potassium supplement may be prescribed by your doctor.
This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths or sunlamps. Use a sunscreen and wear protective clothing when outdoors.
Before having surgery, tell your doctor or dentist that you are taking this medication.
This drug may make you dizzy, drowsy, or cause blurred vision; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages.
To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position.
Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially dizziness.
Torsemide should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.
It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.
See also the How to Use section.
This drug should not be used with the following medication because very serious interactions may occur: cisapride.
If you are currently using this medication, tell your doctor or pharmacist before starting torsemide.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: other drugs that can affect hearing/balance (e.g., ethacrynic acid, aminoglycoside antibiotics such as gentamicin, tobramycin), amphotericin B, cholestyramine, cisplatin, colestipol, corticosteroids (e.g., prednisone), digoxin, lithium, nonsteroidal anti-inflammatory drugs (NSAIDs such as ibuprofen, indomethacin), large doses of aspirin and aspirin-like drugs (salicylates).
Check the labels on all your medicines (e.g., cough-and-cold products, diet aids, NSAIDs for pain/fever reduction) because they may contain ingredients that could increase your blood pressure or swelling (edema). Ask your pharmacist about the safe use of those products.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include fainting, a severe decrease in amount of urine, or severe weakness.
NOTES: Do not share this medication with others. Lifestyle changes such as stress reduction programs, exercise, and dietary changes may increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.
Laboratory and/or medical tests (e.g., blood mineral levels such as potassium, kidney and liver function tests, cholesterol level) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
Have your blood pressure checked regularly while taking this medication. Discuss with your doctor how to monitor your own blood pressure.
MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
MEDICAL ALERT: Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).
Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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