The kinetic profiles of amlodipine and of a sustained release form of diltiazem.

This study in normotensive subjects compared plasma concentrations of amlodipine (5 mg) and of a sustained release form of diltiazem (300 mg) after single and multiple oral dosings of the two drugs. As a consequence of the galenic form of administered formulations, plasma concentration of diltiazem versus time curves exhibited two peaks corresponding to fast and slow releases of diltiazem. Conversely, the curves of amlodipine plasma concentration depicted only one peak. There was less variability in plasma concentrations and in pharmacokinetics with amlodipine than with diltiazem after both single and multiple oral dosings of the two drugs. These results suggested that amlodipine displayed less variability in blood pressure response at steady-state. The rate of decrease in plasma levels of diltiazem between 24 and 48 hours post-dose was higher than that of amlodipine. So, even after a missed dose, there is only a small decline in plasma concentrations of amlodipine and therefore it suggests a small repercussion on the blood pressure attenuation.