A new intranasal spray formulation of propranolol was developed to provide beta-adrenergic blocking medication on an immediate basis to patients with angina pectoris. The effects of this spray or placebo were assessed in 16 patients with effort-induced angina in a blinded, randomized, cross-over design study that compared placebo with intranasal propranolol spray (5 mg/puff) 15 minutes before exercise on a treadmill (Bruce protocol). One week later, each patient, acting as his/her own control, received the alternative treatment and repeated exercise. Mean plasma propranolol level with active therapy was 20 ng/ml. Patients with active spray demonstrated a significant increase in total exercise time than patients taking placebo (530 +/- 197 vs 460 +/- 177 seconds, p = 0.05), an increase in the time to 1 mm ST-segment depression on the electrocardiogram (384 +/- 202 vs 327 +/- 144 seconds, p < 0.05), and an increase in time to onset of angina (452 +/- 149 vs 363 +/- 175 seconds, p = 0.0005). There was a blunting of maximal exercise heart rate with active therapy compared with placebo (120 +/- 13 vs 133 +/- 17 beats/min, p < 0.01), blunting of maximal exercise systolic blood pressure (185 +/- 22 vs 194 +/- 21 mm Hg, p < 0.05), and blunting of peak double product (p < 0.0005), with more modest effects on resting heart rate. Propranolol spray is an effective approach for providing immediate beta blockade and improving exercise tolerance in patients with angina pectoris.