Spironolactone. III. Canrenone--maximum and minimum steady-state plasma levels.

Steady-state plasma levels of canrenone have been examined in 23 healthy men who received repeated doses of spironolactone for 15 days. The dose regimens were 200 mg once a day and 50 mg 4 times a day. With both treatments the steady-state levels were reached after 3 to 4 days. With once-a-day treatment, the maximum and minimum steady-state levels were about 500 and 100 ng/ml, respectively. The minimum levels with treatment 4 times a day were about 200 ng/ml. The post steady-state half-life of canrenone with once-a-day treatment (19.2 +/- 6.57 hr) was longer (p less than 0.01) than the half-life obtained in the 4 times-a-day treatment (12.5 +/- 3.39 hr). The former half-life was similar to the log-linear phase half-life of canrenone in the single-dose studies.