Hypertension The initial dosage of acebutolol in uncomplicated mild-to-moderate hypertension is 400 mg. This can be given as a single daily dose, but in occasional patients twice daily dosing may be required for adequate 24-hour blood-pressure control. An optimal response is usually achieved with dosages of 400 to 800 mg per day, although some patients have been maintained on as little as 200 mg per day. Patients with more severe hypertension or who have demonstrated inadequate control may respond to a total of 1200 mg daily (administered b.i.d.), or to the addition of a second antihypertensive agent. Beta-1 selectivity diminishes as dosage is increased. Ventricular Arrhythmia The usual initial dose of acebutolol is 400 mg daily given as 200 mg b.i.d. Dosage should be increased gradually until an optimal clinical response is obtained, generally at 600 to 1200 mg per day. If treatment is to be discontinued, the dosage should be reduced gradually over a period of about two weeks. Use in Older Patients Older patients have an approximately 2-fold increase in bioavailability and may require lower maintenance doses. Doses above 800 mg/day should be avoided in the elderly.

Two adrenergic receptor antagonists, acebutolol and propranolol, were observed to depress rabbit heart contractile force and adrenaline-stimulated adenylate cyclase activity at 1 X 10-(5) to 1 X 10-(3) M and 1 X 10-(6) to 1 X 10-(3) M concentrations, respectively. Acebutolol depressed sarcoplasmic reticular and mitochondrial calcium uptake at 5 X 10-(3) to 10-(2) M concentrations.