Acute and long term effects of loop diuretics in heart failure

Determining the effectiveness of torasemide and furosemide in heart failure: design of a randomised comparison using the regenstrief medical record system

OBJECTIVE

A state-of-the-art clinical computing system was investigated to test the hypothesis of whether a completely and predictably absorbed loop diuretic (torasemide) offers clinical advantages over a diuretic that is poorly and erratically absorbed (furosemide).

PATIENTS

We enrolled 234 patients with heart failure into this randomised, prospective, open-label study of the effectiveness and cost effectiveness of torasemide and furosemide with a comprehensive electronic medical record called the Regenstrief Medical Record System (RMRS) serving as the primary data repository.

METHODS

The RMRS contained patient data for physician visits, emergency department visits, hospitalisations, laboratory tests, prescription medications, and in- and outpatient service charges. Because these patient data were captured during the course of routine care, there was much efficiency in study data collection and few associated costs. Before the study began, ready access to the RMRS data permitted characterisation of the target study population and an accurate sample size calculation. During the study, programs contained within the RMRS identified patients for recruitment, preserved randomisation, and alerted investigators to important patient events. Quality-of-life instruments programmed into notebook computers were loaded with available RMRS data and then supplemented with primary collection data, thereby permitting paperless data entry.

CONCLUSION

The computing infrastructure used for this study has permitted us to examine an interface between clinical pharmacology and outcomes research within the realm of medical informatics.

Open-label randomized trial of torsemide compared with furosemide therapy for patients with heart failure

PURPOSE

Because the bioavailability of oral furosemide is erratic and often incomplete, we tested the hypothesis that patients with heart failure who were treated with torsemide, a predictably absorbed diuretic, would have more favorable clinical outcomes than would those treated with furosemide.

PATIENTS AND METHODS

We conducted an open-label trial of 234 patients with chronic heart failure (mean [+/- SD] age, 64 +/- 11 years) from an urban public health care system. Patients received oral torsemide (n = 113) or furosemide (n = 121) for 1 year. The primary endpoint was readmission to the hospital for heart failure. Secondary endpoints included readmission for all cardiovascular causes and for all causes, numbers of hospital days, and health-related quality of life.

RESULTS

Compared with furosemide-treated patients, torsemide-treated patients were less likely to need readmission for heart failure (39 [32%] vs. 19 [17%], P <0.01) or for all cardiovascular causes (71 [59%] vs. 50 [44%], P = 0.03). There was no difference in the rate of admissions for all causes (92 [76%] vs. 80 [71%], P = 0.36). Patients treated with torsemide had significantly fewer hospital days for heart failure (106 vs. 296 days, P = 0.02). Improvements in dyspnea and fatigue scores from baseline were greater among patients treated with torsemide, but the differences were statistically significant only for fatigue scores at months 2, 8, and 12.

CONCLUSIONS

Compared with furosemide-treated patients, torsemide-treated patients were less likely to be readmitted for heart failure and for all cardiovascular causes, and were less fatigued. If our results are confirmed by blinded trials, torsemide may be the preferred loop diuretic for patients with chronic heart failure.

Torsemide: a pyridine-sulfonylurea loop diuretic

OBJECTIVE

To review the clinical pharmacology of torsemide and to compare it with currently available loop diuretics, particularly furosemide.

DATA SOURCES

An English-language MEDLINE search, 1985 to October 1994, was used to identify pertinent literature, including review articles.

DATA EXTRACTION

Data from scientific literature were extracted, evaluated, and summarized for presentation. Pivotal and representative studies are discussed relating to the pharmacology, pharmacokinetics, and use of torsemide in patients with congestive heart failure, renal disease, hepatic disease, and hypertension.

DATA SYNTHESIS

Torsemide is a loop diuretic of the pyridine-sulfonylurea class. The bioavailability of torsemide is approximately 80%, with little first-pass metabolism, and torsemide can be given without regard to meals. The serum concentration reaches its peak within 1 hour after oral administration and diuresis lasts approximately 6-8 hours. Torsemide is eliminated both hepatically (80%) and renally (20%) as unchanged drug with an elimination half-life of about 3.5 hours. Because of the high bioavailability, oral and intravenous doses are therapeutically equivalent. Torsemide, and other loop diuretics such as furosemide, are indicated for the treatment of edema associated with congestive heart failure, renal disease, and hepatic disease. They also are indicated for the treatment of hypertension alone or in combination with other antihypertensive agents. Depending on the indication, the recommended initial adult dosage of torsemide is between 5 and 20 mg once daily orally or intravenously. Special dosage adjustments in the elderly are not necessary.

CONCLUSIONS

Torsemide is a loop diuretic similar to furosemide, with similar indications. Torsemide is characterized by good bioavailability and once-daily dosing and, compared with furosemide, provides generally equivalent therapeutic efficacy.