Felodipine, a new calcium antagonist, as monotherapy in mild or moderate hypertension. Cooperative study group.

The role of felodipine, a new calcium antagonist, as monotherapy in mild and moderate hypertension (supine diastolic blood pressure between 95 and 100mm Hg: phase V) was investigated in a placebo-controlled, double-blind study of 109 patients from 13 centres using 3 different doses. After a 2-week placebo run-in phase the patients were randomised in a double-blind fashion to receive felodipine 2.5mg bid (32 patients), 5 mg bid (30 patients), 10mg bid (24 patients) or placebo (25 patients). Clinical and laboratory measurements were performed after 1, 3 and 8 weeks. 94 patients completed the study. Felodipine reduced supine systolic blood pressure by 22mm Hg from baseline after 8 weeks' treatment on 2.5mg bid, 24mm Hg on 5mg bid and 24mm Hg on 10mg bid at 2 hours after dosage. The corresponding reduction in the placebo group was 6mm Hg. There was a reduction in supine diastolic blood pressure from baseline of 13mm Hg on felodipine 2.5mg bid, 14mm Hg on felodipine 5mg bid and 20mm Hg on felodipine 10mg bid, with no reduction in patients receiving placebo. The percentage of patients completing the study who achieved a supine diastolic blood pressure of 90mm Hg or less after 8 weeks' treatment at 2 hours after dosage was 9% on placebo, 67% on felodipine 2.5mg bid, 57% on felodipine 5mg bid and 92% on felodipine 10mg bid; and at 12 hours after dosage those achieving target supine diastolic blood pressure was 17% on placebo, 37% on felodipine 2.5mg bid, 25% on felodipine 5mg bid and 62% on felodipine 10mg bid. Felodipine was generally well tolerated, although 10 patients on felodipine 10mg bid (42%), 1 on felodipine 5mg bid (3%) and 2 on felodipine 2.5mg bid (6%) withdrew from the study because of adverse effects. One serious adverse event, a myocardial infarction, occurred during the study in a patient with a history of postprandial non-exertional chest pain. In conclusion, felodipine monotherapy appreciably reduces blood pressure in mild and moderate hypertension without significant tachycardia in the short term. Doses of felodipine 2.5mg bid and 5mg bid are better tolerated than 10mg bid and can be recommended for initial treatment in this category of patients.