Variability of Blood Pressure in Ambulatory Hypertensive Patients: Effects of Verapamil on Twice and Thrice Daily Dose Regimens

ABSTRACT The antihypertensive effects of verapamil over 24 hours were assessed on twice and thrice daily dose regimens on 12 patients (25–65 years of age; mean age 50) with essential hypertension (WHO stages I–II) in a randomised, double-blind, cross-over trial. After a dose titration period starting with either verapamil 80 mg tid or 120 mg bid the patients kept their maintenance dose (240, 360 or 480 mg daily) for 4 weeks before crossing over to the other administration schedule. Repeated ambulatory blood pressure (BP) curves were recorded in 10 patients with a non-invasive portable device (Pressurometer III, Del Mar Avionics). The BP reductions (causal BP values) obtained by 2- and 3-dose regimens were of similar magnitude (from 170±19/105±8 on placebo to 140±17/87±7 and to 146±14/88±8 by 2- and 3-dose respectively). Analyses of BP curves revealed close similarity in profiles on the two dose regimens, although DBP was significantly (p<0.05) lower by 3-dose as compared to 2-dose regimen during the period 0.00–2.59 a.m. Long-term (circadian rhythm) and short-term variability did not differ between the regimens. Despite the slight difference in DBP curves after midnight, the overall impression is that verapamil given both twice and thrice daily provides adequate BP control throughout 24 hours.