Nifedipine + Atenolol is Effective Antihypertensive Therapy But doubling the nifedipine dose increases the side effect frequency

A double-blind crossover study compared the antihypertensive efficacy and tolerability of atenolol administered alone and in combination with nifedipine. After a 4-week single-blind run-in on atenolol 50mg bid, 25 patients with a sitting diastolic BP > 95mm Hg and < 120mm Hg were randomised to receive atenolol 50mg, ate nolo I 50mg + nifedipine 20mg and atenolol 50mg + nifedipine 40mg twice daily for 4 weeks each, with no washouts between treatments.

Mean sitting BP was 174/1 06mm Hg after the run-in, 171/1 07mm Hg after atenolol monotherapy and 156/97 (p < 0.01 vs ate nolo I alone) and 157/99mm Hg (p < 0.01 vs ate nolo I alone) after the lower and higher dose combinations, respectively. Standing BPs were similarly affected. Variations in heart rate did not differ significantly between the 3 drug treatments. Ten patients experienced 12 adverse effects on atenolol monotherapy, 5 patients experienced 8 adverse effects on the low dose combination and 10 patients experienced 23 adverse effects, particularly flushing/erythema (n = 5) on the high dose combination.

Thus, ' •.. the addition of nlfedlplne 20mg twice dally to atenolol 50mg twice daily significantly improves hypotensIve efficacy 12h post-dose, and also tolerability, but . .. doubling the nifedipine dose merely doubles the side-effect burden without any enhancement of the antihypertensive efficacy'. Maclean D. Mitchell ET, Coulson RR, Fitzsimons T J, McDevitt DG British Journal of Clinical Pharmacology 25 425-431, Apr 1988 'm

8 INPHARMA" 4 June 1988 0156-2703/88/0604-0008/0501 .00/ 0 © ADIS Press