Blood pressure and cationic transport systems during combined calcium channel blocker and calcium administration in males.

A double-blind, placebo-controlled parallel study was conducted on the effects of a high daily oral supplementation of 1 g elemental calcium, given twice daily for 16 weeks, followed by additional administration of 2 mg b.i.d. lacidipine or placebo for 8 weeks, on blood pressure, intracellular cationic concentrations and transport systems, plasma total calcium, ionized calcium and calciotropic hormones in normal male subjects. No significant difference in the effect of lacidipine vs. placebo on standing or recumbent systolic or diastolic blood pressure or heart rate was found between calcium- and placebo-treated subjects. The difference in lacidipine effect on erythrocyte Mg2+ concentration and platelet membrane cholesterol content between the placebo and calcium groups was statistically significant. There was no additional effect between groups of lacidipine on erythrocyte and platelet intracellular Ca2+, Na+ and K+ concentrations or transport systems and on plasma Ca2+ levels and calciotropic hormones. Combined calcium and lacidipine administrations in normal male subjects did not induce antihypertensive effects different from those induced by either agent alone.