In a randomized double-blind, parallel group study, the effects of
piretanide on serum
electrolytes and on symptoms of
congestive heart failure were compared with those of the combination
piretanide plus
triamterene in out-patients with mild to severe
congestive heart failure. A total of 60 patients entered the study; 13 patients were excluded from the statistical analysis (4 due to premature end of the study, 2 due to dose increase, 7 due to concomitant medication (
antihypertensive or antihypotensive agents), so that the results of 47 patients were statistically analyzed, 26 of them in the
piretanide and 21 of them in the
piretanide plus
triamterene group.
Piretanide (6 mg once daily) and
piretanide plus
triamterene (6 mg + 50 mg once daily) both produced a significant reduction in certain symptoms of
congestive heart failure which was evident at 2 weeks and was maintained and further enhanced over the ensuing 12-week trial period. Improvement in a number of symptoms of
congestive heart failure was attained in 54% of the patients in the
piretanide group and 67% in the
piretanide plus
triamterene group. This difference, however, was not clinically relevant, since the symptoms which are expected to improve in this short time showed no great difference between the two groups. There were no significant changes in serum
potassium and serum
magnesium within groups or differences between the groups. There were decreases in serum
sodium,
calcium and inorganic
phosphorus in the
piretanide plus
triamterene group. In the
piretanide group, only a temporary drop in inorganic
phosphorus was observed.(ABSTRACT TRUNCATED AT 250 WORDS)