COMPARATIVE EFFICACY OF 2 LONG-ACTING FORMULATIONS OF NIFEDIPINE IN THE TREATMENT OF HYPERTENSION

OBJECTIVE: To compare the antihypertensive effects and incidence of si de effects of two formulations of nifedipine: a prolonged action (PA) tablet bid and a gastrointestinal therapeutic system (GITS) tablet onc e daily. DESIGN: Patients with controlled hypertension (diastolic bloo d pressure less than 90 mmHg) on nifedipine-PA 10 mg (n=74) or 20 mg ( n=99) bid were enrolled into an open label study consisting of six wee ks of previous nifedipine-PA followed by six weeks of nifedipine-GITS therapy. Nifedipine-GITS was increased from 30 mg to 60 mg daily if th e patient's diastolic blood pressure increased by at least 10 mmHg com pared with the value after six weeks of nifedipine-PA. MAIN RESULTS: B lood pressure after six weeks of nifedipine-PA 10 mg (142+/-1/86+/-1 m mHg) decreased (P<0.01) after conversion to nifedipine-GITS 30 mg (137 +/-1/84+/-1 mmHg). Blood pressure values for nifedipine-PA 20 mg patie nts were unchanged after conversion to nifedipine-GITS; 74 patients re ceived nifedipine-GITS 30 mg and 14 patients required titration up to nifedipine-GITS 60 mg daily. Sixteen patients withdrew on nifedipine-P A and five withdrew on nifedipine-GITS, mostly for reasons unrelated t o drug therapy. Twenty-three patients experienced adverse events on ni fedipine-PA versus 20 patients on nifedipine-GITS therapy. CONCLUSIONS : Patients whose hypertension is controlled by nifedipine-PA 10 or 20 mg bid can be successfully converted to nifedipine-GITS with most pati ents remaining normotensive on 30 mg daily.