Are there differences in the effects of long-acting calcium antagonists on ambulatory blood pressure? Extended-release nisoldipine versus amlodipine as a model.

: BACKGROUND: Twenty-four-hour ambulatory blood pressure monitoring (ABPM), which provides important information regarding mean 24 h efficacy, variability of effect during sleeping-awake cycles, and effects on the early morning surge in blood pressure, is a sensitive method for evaluating efficacy of antihypertensive agents. Extended-release nisoldipine and amlodipine are long-acting dihydropyridine calcium antagonists used for the treatment of hypertension. Because these agents have different pharmacokinetic profiles, 24 h ABPM could provide clues regarding their different effects on blood pressure. OBJECTIVE: To assess the effects of extended-release nisoldipine and amlodipine on 24 h ambulatory blood pressure control and heart rate. METHODS: After completion of a 3-4 week placebo run-in period, 100 patients were randomly allocated to double-blind treatment with 10-40 mg extended-release nisoldipine or 2.5-10 mg amlodipine for 8 weeks, starting at the lowest dose. Medications were titrated at 2-week intervals on the basis of office blood pressures in seated patients. Twenty-four-hour ABPM was performed at placebo baseline and at the end of double-blind therapy. RESULTS: Extended-release nisoldipine and amlodipine provided equivalent mean 24 h changes in blood pressure [systolic blood pressure (SBP)/diastolic blood pressure decreases by 9.8/7.1 and 8.0/6.0 mmHg, respectively] and heart rate. These two treatments also provided similar changes in blood pressure at trough (22-24 h after dosing; decreases by 10.4/7.2 and 10.1/7.3 mmHg, respectively). The antihypertensive effects of amlodipine during the awake and sleeping intervals were similar (decreases by 9.6/5.9 and 9.9/5.8 mmHg, respectively, NS); whereas the effect of nisoldipine during the awake interval was significantly greater than its effect during the sleeping interval (decreases by 12.4/8.0 and 8.9/4.3 mmHg, respectively, P = 0.08/0.01). Furthermore, extended-release nisoldipine, but not amlodipine, blunted the rate of rise in early morning SBP. CONCLUSIONS: Extended-release nisoldipine and amlodipine have similar effects on mean 24 h and trough blood pressures. However, different effects during the sleeping and awake intervals and on the rate of rise in early morning SBP were observed with nisoldipine.