Torsemide - Demadex Part Two
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 andmetabolic alkalosis, an aldosterone antagonist or potassium-sparing drug should be used concomitantly with DEMADEX.
Tinnitus and hearing loss (usually reversible) have been observed after rapidintravenous 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 highplasma 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- orhypochloremia, hyper- or hypokalemia, acid-base abnormalities, and increasedblood 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 tohypertensive 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 Statesantihypertensive 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.
Potassium: See WARNINGS.
Single doses of DEMADEX increased the urinary excretion of calcium by normal subjects, but serum calcium levels were slightly increased in 4- to 6- weekhypertension 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.
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 heartfailure, 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.
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.
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 triglyceridesof 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.
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 serumalkaline 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 tubularinjury, 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 testin bacteria (with and without metabolic activation), tests for chromosomeaberrations 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 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 fetalossification) 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.
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.
Safety and effectiveness in pediatric patients have not been established.
Administration of another loop diuretic to severely premature infants with edemadue 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.
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.
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.
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.
DEMADEX is contraindicated in patients with known hypersensitivity to DEMADEX or to sulfonylureas.
DEMADEX is contraindicated in patients who are anuric.