Diltiazem in comparison with metoprolol in stable angina pectoris.

The efficacy of diltiazem in comparison with metoprolol in chronic stable angina was assessed in 33 male patients during a 15-week blind cross-over study. After an initial two-week run-in period, baseline measurements were made. Subsequently, the patients entered a blind cross-over study consisting of two six-week treatment periods with diltiazem 240 mg (60 mg q.i.d.) or metoprolol 200 mg (100 mg b.i.d.). Dose adjustment to either 360 mg diltiazem (120 t.i.d.) or 400 mg metoprolol (200 b.i.d.) was allowed two weeks after the start of treatment. There was a one-week washout period between the two treatment periods. Compared to baseline values both drugs reduced the number of anginal attacks (diltiazem - 55%, P = 0.02; metoprolol - 73%, P = 0.01) and showed improvement of the measured exercise variables (exercise duration: diltiazem + 16%, P less than 0.001; metoprolol + 4%, P = NS; time to angina: diltiazem + 21%, P = 0.02, metoprolol + 14%, P = NS; maximal ST-depression: diltiazem + 13%, P = NS, metoprolol + 33%, P = 0.002). No significant change in LVEF was noticed. Both drugs reduced the mean heart rate on Holter tape (diltiazem - 11%, P = 0.006; metoprolol - 14%, P = 0.004). No effects on conduction were noticed. Although at the borderline of significance, diltiazem increased the total exercise duration as compared to metoprolol (16 vs. 4%, P = 0.05). It is concluded that diltiazem improves exercise tolerance in patients with stable angina pectoris and appears to be a safe and effective alternative to the beta-blocking agent metoprolol.(ABSTRACT TRUNCATED AT 250 WORDS)