A double-blind comparison of felodipine and hydrochlorothiazide added to metoprolol to control hypertension.

Seventy-six uncomplicated hypertensive patients treated in General Practice, whose seated diastolic blood pressure (Phase V) (dBP) remained greater than or equal to 95 mmHg after a minimum of 4 weeks treatment with metoprolol 50 mg b.i.d. as antihypertensive monotherapy, were randomized to receive the selective 'calcium antagonist' felodipine 5 mg b.i.d. or hydrochlorothiazide 12.5 mg b.i.d. in addition to metoprolol 50 mg b.i.d. The trial duration was 8 weeks, the dose of the felodipine or hydrochlorothiazide being doubled after 4 weeks if 'control' of BP (dBP less than 90 mmHg) was not achieved on the initial doses. Over the trial period of 8 weeks, felodipine reduced dBP from 102 to 85 mmHg and hydrochlorothiazide from 101 to 91 mmHg; the dBP reduction in the felodipine group was greater than that in the hydrochlorothiazide group (17 vs 9 mmHg) and the attained dBP lower in the felodipine group. About half of the patients in each group required the higher dose. Both regimes were effective and well tolerated. In the dosages used, felodipine was a slightly more effective antihypertensive drug than hydrochlorothiazide when added to metoprolol. There was no apparent difference in the tolerability of the two regimes.