The cardiovascular effects of bolus doses of doxacurium 0.037 mg kg-1 were compared with those following equipotent doses of pancuronium (0.09 mg kg-1) and vecuronium (0.075 mg kg-1) and with those following high-dose doxacurium (0.075 mg kg-1), in patients with coronary artery disease. Anaesthetic technique comprised premedication with lorazepam, papaveretum and hyoscine, induction with diazepam, fentanyl, thiopentone, atropine and suxamethonium, and the trachea was intubated. At least 20 min later, during stable nitrous oxide in oxygen anaesthesia, a single bolus of neuromuscular blocking drug was administered and the effects measured at 1, 5 and 10 min. There was a small decrease in heart rate following doxacurium 0.075 mg kg-1, but no other significant or dose-related changes in mean heart rate, arterial pressure or cardiac index with doxacurium. Similar results were found following vecuronium, but the reduction in heart rate was more pronounced. In contrast, significant increases in mean arterial pressure, heart rate and cardiac index occurred after pancuronium.