hypotensive interaction between nifedipine and atenolol

HYPOTENSIVE INTERACTION BETWEEN NIFEDIPINE AND ATENOlOl

15 patients with hypertension and stable angina, were controlled on atenolol SO-I OOmg / day (+ diuretic and prazosin in some).Nifedipine 1Omgbid was added to the regimen for 6 weeks, preceded and followed by two 6-week periods of nifedipine placebo.In the combination phase, BP was reduced to 148/94mm Hg, from 164-165/102-1 OSmm Hg during atenolol + nifedipineplacebo, but the severity ofangina was unaltered. In lpatient on the combination therapy, however, BP dropped over I month to80-90/60mm Hg. He became weak, but his angina did not worsen. Atenolol was withdrawn and pulse and BP improved but thepatient suffered a period of severe unstable angina, with persistent chest pain. Atenolol was therefore restarted and the nifedipinewas withdrawn. The BP remained satisfactory but the angina was relieved.Thus the addition of nifedipine to ~-blockade may result in a predominantly hypotensive effect without much improvement ofangina. Ifexcessive hypotension results, the nifedipine rather than the ~-blocker should be withdrawn.()pie. L.H. and White. D.A.: British Medical Journal 281: 1462 (Nov 29. 1980)

6 INPHARMA 13Dec 1980 0156-2703/80/1213.0006 $00.50/0 ©ADIS Press