Slow-release oral isradipine in the treatment of essential hypertension

Abstract The antihypertensive efficacy of slow-release oral (SRO) isradipine was evaluated in 392 patients (mean age, 53 ± 9 years) with mild-to-moderate essential hypertension (diastolic blood pressure [DBP] 96 to 110 mm Hg). Patients from 35 hospitals throughout Italy participated in this 26-week study. After a 2-week placebo run-in period, patients were treated with 5 mg/d of isradipine; 6 weeks later, 10 to 20 mg of enalapril was added if DBP was not adequately reduced. At baseline and after 6 and 26 weeks of treatment, ambulatory 24-hour blood pressure (BP) recordings were made with measurements every 15 minutes during waking hours (7 am to 11 pm ) and every 30 minutes during nighttime (11 pm to 7 am ). Seated office BP was significantly reduced by isradipine alone and in combination with enalapril: mean overall group casual BP measurements fell by 15 mm Hg (systolic blood pressure [SBP]) and 10 mm Hg (DBP) at 6 weeks and 22 mm Hg (SBP) and 16 mm Hg (DBP) at 26 weeks compared with baseline. There was no significant difference between the two regimens. Mean 24-hour ambulatory BP of all 392 patients was lower with isradipine treatment at weeks 6 and 26, without changes in 24-hour BP profiles. The most frequent side effects observed were headache, flushing, ankle edema, and palpitations. These were responsible for a 4.8% dropout rate. No clinically important variations were observed in blood chemistries. The results of this large-scale study confirm that 5 mg/d of isradipine SRO is effective and well tolerated in the treatment of patients with mild-to-moderate essential hypertension. Analysis of BP profiles showed that, despite the marked antihypertensive effect persisting over 24 hours, the physiologic circadian BP rhythm was maintained.