Effects of cilnidipine, a novel dihydropyridine calcium antagonist, on autonomic function, ambulatory blood pressure and heart rate in patients with essential hypertension

Aims The aim of the present study was to evaluate the effects of cilnidipin e, a novel dihydropyridine calcium antagonist, on autonomic function, ambul atory blood pressure and heart rate in patients with essential hypertension . Methods Ten inpatients with mild to moderate essential hypertension (four m en and six women; age: 44-64 years) underwent a drug-free period for 7 days and a treatment period with cilnidipine 10 mg orally for another 7 days, i n a randomized crossover study. On the sixth day of each period, they under went autonomic function tests including a mental arithmetic test, a cold pr esser test and a Valsalva manoeuvre. After these tests, 24 h ambulatory blo od pressure, heart rate, and the electrocardiogram R-R intervals were monit ored every 30 min. A power spectral analysis of R-R intervals was performed to obtain the low-and high-frequency components. Results Cilnidipine significantly decreased the 24 h blood pressure by 6.5 +/- 1.7 mm Hg systolic (mean+/-s.e.mean; P<0.01) and 5.0+/-1.1 mmHg diastol ic (P<0.01), whereas cilnidipine did not change heart rate or any indices o f power spectral components. During the cold presser test, the maximum chan ge in systolic blood pressure and percentage changes in both systolic and d iastolic blood pressures were significantly lower during the treatment peri od with cilnidipine than during the drug-free period. The baroreflex sensit ivity measured from the overshoot phase of the Valsalva manoeuvre did not d iffer significantly between the two periods. Conclusions Cilnidipine is effective as a once-daily antihypertensive agent and causes little influence on heart rate and the autonomic nervous system in patients with mild to moderate essential hypertension. Moreover, it is suggested that cilnidipine has an additional clinical benefit in the inhibi tion of the presser response induced by acute cold stress.