Comparison between L-type and N/L-type calcium channel blockers in the regulation of home blood-pressure variability in elderly hypertensive patients.

Recent studies suggest that L-type calcium channel blockers (CCBs) contribute to reducing blood pressure (BP) variability. We investigated whether inhibition of the N-type calcium channel has an additional effect on BP variability by comparing the effect of L-type and L/N-type CCBs on home BP variability in elderly hypertensive patients. Twenty-six hypertensive patients (≥65 years) were subjected to repeated changes with the administration of amlodipine (L-type CCB) and cilnidipine (L/N-type CCB) every 2 months. They measured the home BP in the morning and evening, and the coefficient of variation (CV) was calculated. We measured the brachial-ankle pulse wave velocity (baPWV) and urinary catecholamine excretion as an index of the arterial stiffness and sympathetic nerve activity, respectively. There was no difference in the effect of both drugs on the CV in the morning and evening, while amlodipine was associated with a modestly higher pulse rate and lower BP than cilnidipine. By comparing individual patient data for the CV with each drug, we found that higher urinary catecholamine excretion was associated with the effectiveness of cilnidipine over amlodipine in the BP variability in the morning, which was not the case in the evening. In contrast, lower baPWV was associated with the effectiveness of amlodipine over cilnidipine on BP variability in the evening. Lower baPWV was also associated with lower BP variability in the evening. Cilnidipine has a similar capacity as amlodipine in reducing home BP variability, but the underlying mechanisms in reducing BP variability may differ.