EFFECT OF BETA-BLOCKERS ON EXERCISE DOUBLE PRODUCT (SYSTOLIC BLOOD-PRESSURE X HEART-RATE)

1 The effect of single oral doses of six beta‐receptor antagonists on exercise‐induced changes in double product (systolic blood pressure x heart rate) were studied in 25 human volunteers. 2 Three doses of propranolol, nadolol, oxprenolol, pindolol, timolol and atenolol were selected for study on the basis of in vivo beta‐blocking potency. 3 Although all beta‐blockers studied reduced the double product response to exercise, the pharmacodynamics of this effect differed markedly. 4 Pharmacodynamic half‐lives, estimated for the drug tested, were 39 h for nadolol, atenolol 21 h, timolol 15 h, oxprenolol 13 h, propranolol 11 and pindolol 8 h. 5 These results suggest that the clinical choice of a beta‐blocker with the least problems of compliance can be made on the basis of pharmacodynamics as well as pharmacological profile. 1979 The British Pharmacological Society