Efficacy of slow-release oral isradipine in moderate-to-severe hypertension with add-on spirapril.

The new slow-release oral formulation (SRO) of isradipine, a dihydropyridine calcium antagonist, was evaluated in 57 patients who had moderate-to-severe hypertension following a 2-week wash-out period and a 2-week placebo period. The angiotensin-converting enzyme (ACE) inhibitor spirapril, at a dose of 6 mg/day, was added to the treatment of those not responding to 5 mg/day isradipine SRO alone. After 4 weeks of active treatment, isradipine alone normalized blood pressure (diastolic blood pressure < or = 90 mm Hg) in 38 (66.6%) patients whereas a further 4 weeks of treatment with the combination of isradipine and spirapril led to normalization in 14 of the 19 (73.7%) patients with partial or nil blood pressure responses. Side-effects were mild and transient and were observed in nine patients (15.8%). Isradipine SRO is an effective and well-tolerated antihypertensive agent and combination with spirapril appears to enhance its efficacy without an increase in side-effects.