A comparison of two cardioselective beta-blockers with different ancillary properties in the treatment of hypertension.

In a double-blind crossover study the antihypertensive effect of acebutol (I.S.A. and M.S.A.) 400 to 800 mg daily was compared with that of metoprolol (non-I.S.A. and non-M.S.A.) 200 to 400 mg daily. Blood pressure and heart-rate were measured sitting, lying and post-exercise. Twenty-eight patients entered the trial, but 4 were withdrawn for reasons not connected with active treatment. There was no significant difference between the drugs in their ability to reduce the systolic and diastolic blood pressure sitting, lying or post-exercise or reduce the heart-rate post-exercise. Metoprolol reduced the heart-rate sitting and lying to a significantly greater degree (p less than 0.05) than acebutolol. While the antihypertensive effect seems to be entirely dependent on beta-blockade, the I.S.A. may still have some value for patients with a low heart rate at rest.