[Treatment of essential hypertension with felodipine or atenolol as first line therapy. Comparative double-blind randomized study].

This study involved 113 patients (mean age 50 +/- 14 years) with diastolic blood pressure above 95 mmHg. The patients abstained from taking any antihypertensive drug and received a placebo for one week before entering felodipine, a new calcium antagonist (5 mg x2/day for 2 weeks, then 10 mg x2/day) or atenolol (100 mg/day). There was no significant difference between the two treatment groups. Atenolol tended to be more effective in young subjects and felodipine in subjects aged 60 years or more. Heart rate was more reduced by atenolol than by felodipine (P less than 0.01). Undesirable side-effects were recorded by means of an open questionnaire. Their incidence was 23 per cent during the week under placebo and 84 per cent and 80 per cent respectively during treatment with felodipine or atenolol. The most frequent side-effects were oedema of the ankles and headache under felodipine, fatigue and headache under atenolol. Alkaline phosphatase levels were higher in the felodipine group (P less than 0.05), and a slight rise in blood potassium level (0.2 mmol/l) was noted in the atenolol group (P = 0.001), but these values remained within normal limits.