Propranolol increases oxygen utilization during hypoxia.

The effects of propranolol on whole body oxygen consumption and blood oxygen content were measured in the dog during extreme hypoxic conditions. At 9% inspired oxygen four of eight control animals died within 40 min. An identical second group was pretreated with propranolol and none died during the same hypoxic stress. Hypoxia decreased oxygen consumption in both groups, but the decrease was less in the propranolol-pretreated dogs. A second set of 16 dogs was ventilated with 10% oxygen and all animals survived. A similar, although less pronounced, effect on oxygen consumption was noted and propranolol once again lessened the hypoxia-induced decrease in oxygen consumption. With hypoxaemia, metabolic acidosis developed in all animals and the arterio-venous oxygen content difference decreased; however, propranolol lessened the acidosis and the decrease in arterio-venous oxygen content difference. We conclude that, during hypoxia, propranolol increases oxygen utilization by the tissues and this might account for better survival.