Sustained Blood Pressure Control with Controlled‐Release Isradipine (Isradipine‐CR)

The safety and efficacy, as measured by peak/trough blood pressure reduction, of a new, once‐daily, controlled‐release formulation of isradipine (isradipine‐CR, ICR) were evaluated in patients with mild to moderate essential hypertension during a nine‐week trial. After a 3‐week placebo washout period, patients with a sitting diastolic blood pressure between 100 and 114 mm Hg were randomized to either 1 of 4 ICR treatment groups or placebo. Of 402 randomized patients, 384 completed the study (placebo = 77, ICR‐5 mg = 76, ICR‐10 mg = 76, ICR‐15 mg = 78, and ICR‐20 mg = 77). Peak and trough post‐dose blood pressure responses and heart rates were monitored for both the sitting and upright positions. Blood chemistries, urinalyses, complete blood counts, and electrocardiograms were done during the study. Both sitting and upright blood pressures decreased with the 5‐ ( P < .05), 10‐, 15‐, and 20‐mg ( P < .001) once‐daily ICR doses. The peak blood pressure reduction for all ICR doses occurred at 8 to 10 hours post‐dose. Maximum peak/trough blood pressure response, achieved with the 10‐mg dose, was similar with that of 15 and 20 mg of ICR. No serious clinical or metabolic side effects were noted, except ankle edema, which was dose dependent but did not require discontinuation of treatment. Based on these results we concluded that (1) ICR provided effective peak and trough blood pressure control after once‐daily dosing (5–20 mg) in hypertensive patients, (2) it was safe and well tolerated, and (3) the best overall results were achieved with the 10‐mg once‐daily dose .