This was a comparison of the effects of isradipine and metoprolol on sleep apnea syndrome in 12 hypertensive men who were habitual snorers. Each patient received double-blind isradipine 1.25-2.5 mg twice daily or metoprolol 50-100 mg twice daily after a 4-week placebo period. Static charge-sensitive bed examination was performed during the placebo period and 5-7 weeks after starting treatment. The number of obstructive breathing patterns was increased by metoprolol in five patients, remained the same with isradipine in four, and was decreased by metoprolol in one patient and by isradipine in two. Obstructive patterns increased in the metoprolol group from 24 +/- 26% to 32 +/- 31% and decreased in the isradipine group from 21 +/- 23% to 19 +/- 25% (p less than 0.05, Mann-Whitney U test). Neither drug had a significant effect on blood pressure values. There was no significant difference in oxygen desaturation or in the amount of quiet sleep in either treatment group. On the basis of these results, it would appear that isradipine is more suitable than metoprolol for the treatment of hypertension in patients who are habitual snorers.