Pharmacokinetics of pengitoxin and its therapeutic efficacy in congestive heart failure.

In a therapeutic study, 120 inpatients suffering from congestive heart failure were treated with a daily maintenance dose of 0.3 mg pengitoxin (penta-acetyl-gitoxin) over several weeks or months. The plasma level and the glycoside concentration in urine were measured by radioimmunoassay. The therapeutic effects were evaluated considering clinical signs and criteria following the functional capacity according to the New York Heart Association (NYHA). In 27 patients both plasma and urine concentration were measured during 2 weeks after the beginning of the pengitoxin therapy. On the 3rd day of the pengitoxin dosage schedule, a mean plasma level of 18.1 ng.ml-1 (SD 5.1 ng.ml-1) was measured. During this day 26.6% of the daily administered glycoside dose was excreted in urine. In 26 of the 120 patients the mean steady state plasma level was between 7.6 and 22.5 ng.ml-1. A maximum of frequency was found in the 17.6 to 22.5 ng-subclass. In 118 patients the mean urinary excretion of 16-acetyl-gitoxin reached 24.7% (SD 11.8%) of the administered dose. The creatinine clearance and the 16-acetyl-gitoxin plasma level did not correlate, while between the renal clearance values of creatinine and the glycoside a correlation was found, however, it was of no significance for dosage schedules in patients with impaired renal function. After treatment, the NYHA classes III and II were reached in 57 patients; in 3 patients suffering from renal diseases, the NYHA class I remained unchanged. In 90 patients the clinical signs improved and in 27 patients the clinical situation remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)