The effects of bisoprolol on transient myocardial ischemia have been compared with those of nifedipine in patients with coronary artery disease in end-stage renal failure maintained on haemodialysis. We also evaluated the tolerability of both drugs. Sixty patients (42 males, 18 females, mean age 52 +/- 4 years) in renal failure maintained on haemodialysis, with coronary artery disease and more than four significant episodes of transient myocardial ischemia (> or = 1 min) during 48-hour Holter monitoring, were included in the study. All cardiovascular drugs were discontinued > or = 6 days before this 48-hour ambulatory ECG monitoring, with the exception of sublingual nitrates allowed for relief of anginal attacks. Patients were then randomized to receive either bisoprolol or nifedipine for 2 weeks. After a 15-day wash-out period, they were crossed over to receive either bisoprolol or nifedipine for other 2 weeks. Statistical analysis was carried out using the Student's t test. A p value < 0.01 was considered significant. Both bisoprolol and nifedipine reduced number and duration of transient ischemic episodes as well as the total ischemic burden. Reductions were statistically significant for both antianginal drugs. Only bisoprolol was effective in silent ischemia (p < 0.001). It also reduced heart rate (p < 0.001), while nifedipine raised it (p < 0.001). Both drugs reduced systolic and diastolic blood pressure. The circadian variations of transient ischemic episodes showed two peaks in the 24 hours. Both peaks were reduced with bisoprolol. Nifedipine brought a clear overall reduction in the number of episodes but the circadian pattern was unchanged. During the study, 10 patients taking bisoprolol and 12 patients taking nifedipine had drug adverse effects. No one of them had to be withdrawn from treatment. In conclusion, bisoprolol seems to be more useful than nifedipine because its effects, in transient ischemic episodes, are greatly superior to those of nifedipine, and because it is effective also in silent ischemia. Both drugs showed a good tolerability in these patients. Bisoprolol, reducing the two daily peaks of ischemic episodes frequency, has a protective role towards mortality due to coronary artery disease.