The effect of 8 weeks treatment with the calcium antagonist felodipine on blood pressure, heart rate, working capacity, plasma renin activity, plasma angiotensin II, urinary catecholamines and aldosterone in patients with essential hypertension.

The effect of 8 weeks treatment with the calcium antagonist felodipine--a new long-acting dihydropyridine derivative--in a dose of 10 mg twice daily was studied in 10 male patients with essential hypertension, WHO grade I-II, aged 25-62 years. Diastolic blood pressure was reduced in supine and upright position. Systolic blood pressure was reduced only in the upright position. Heart rate was unchanged in the supine and decreased in the upright position. During dynamic exercise blood pressure was reduced. The maximal working capacity decreased, whereas the maximal heart rate attained was unchanged. Twenty-four hour urinary noradrenaline excretion, plasma renin activity and 24 h urinary aldosterone excretion were increased. Plasma angiotensin II and 24 h urinary adrenaline excretion were unchanged. In conclusion, felodipine is an effective long-acting blood pressure lowering drug with minor side effects. After 8 weeks on felodipine treatment heart rate was not increased, although the activity of the sympathetic nervous system and the renin-aldosterone system seemed enhanced.