[Pharmacodynamics and pharmacokinetics of bemetizid in comparison with hydrochlorothiazide. A controlled human pharmacologic study of acute effects].

Pharmacodynamics and Pharmacokinetics of Bemetizide Compared with Hydrochlorothiazide/Controlled clinical study of acute effects Bemetizide in doses of 1, 5, 10, 20, 50 mg versus 25 mg of hydrochlorothiazide were examined in a placebo-controlled randomized single-dose study under standardized conditions in normal male volunteers. The diuretic effects of bemetizide and hydrochlorothiazide were qualitatively equal, though after higher doses bemetizide showed greater maximal, statistically significant effects on the excretion of sodium, chloride and urine volume (relative efficacy). A trend to increased elimination of potassium was detectable. Diuresis of calcium and magnesium and pH of urine were unchanged. The effects of the reference dosis of hydrochlorothiazide were constantly lower than those of higher doses of bemetizide conferring to the 24-h aliquot and the fractioned samples. The action of both substances began within 1 to 2 h after oral application exceeding 24 h. Kinetics of effects and pharmacokinetics were closely correlated. The evidence of dose-dependent kinetics for bemetizide supports the assumption, that it is absorbed incompletely in higher doses. Because of the lack of a parenteral preparation it is not possible to provide reliable information on the maximal potency of bemetizide.