Acute and long-term haemodynamic effects of propranolol and indenolol in hypertension

The haemodynamic effect of indenolol, a beta-adrenoceptor blocker with intrinsic sympathomimetic activity (ISA) in animals, has been evaluated in a double-blind cross-over randomized trial after acute (3 days) and long-term treatment (28 days), in 12 hypertensive patients in comparison with that of propranolol. Patients were evaluated at rest and during isometric exercise (hand grip). The overall acute effect of both beta-adrenoceptor blocking drugs was to decrease mean blood pressure, heart rate and cardiac output, while total peripheral resistance increased. In the long-term studies the haemodynamic effect of propranolol was still characterized by cardiodepression and unchanged peripheral resistance. Patients on the long-term treatment with indenolol showed normal cardiac output and reduced total peripheral resistance. The data are compatible with a relatively strong ISA of indenolol, which would be responsible for the haemodynamic pattern observed during chronic treatment.