Adult: Initially, 300 mg tid. Max: 1,200 mg daily. Elderly: Dose reduction may be required. Do not exceed 800 mg daily.
Oral Hypertension
Adult: Initially, 400 mg once daily or 200 mg bid. If response is inadequate within 2 weeks, may increase the dose up to 400 mg bid. Max: 1,200 mg daily. Elderly: Dose reduction may be required. Do not exceed 800 mg daily.
Oral Angina pectoris
Adult: Initially, 400 mg once daily or 200 mg bid. Elderly: Dose reduction may be required. Do not exceed 800 mg daily.
Oral Cardiac arrhythmias
Adult: Initially, 200 mg bid, may increase according to response up to 1,200 mg daily in divided doses. Elderly: Dose reduction may be required. Do not exceed 800 mg daily.
Renal Impairment
CrCl (mL/min)
Dosage
<25
Reduce dose by 75%.
25-49
Reduce dose by 50%.
Administration
May be taken with or without food.
Contraindications
Cardiogenic shock, 2nd- and 3rd-degree heart block (without a functioning artificial pacemaker), sick sinus syndrome, marked bradycardia (<45-50 bpm), uncontrolled heart failure, metabolic acidosis, severe peripheral circulatory disorders, untreated phaeochromocytoma.
Special Precautions
Patient with bronchospastic disease, diabetes mellitus, mesenteric vascular disease, Prinzmetal's angina, thyroid disease, psoriasis, history of severe anaphylaxis to allergens, myasthenia gravis. May mask signs or symptoms of thyrotoxicosis and hypoglycaemia (e.g. tachycardia). Avoid abrupt withdrawal. Patient undergoing surgery. Renal and hepatic impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Bradycardia. Cardiac disorders: Heart failure. Eye disorders: Visual impairment, conjunctivitis, dry eye, eye pain. Gastrointestinal disorders: Nausea, diarrhoea, vomiting, abdominal pain. General disorders and administration site conditions: Fatigue. Hepatobiliary disorders: Hepatic abnormality. Immune system disorders: Antinuclear antibody. Rarely, SLE. Musculoskeletal and connective tissue disorders: Joint pain, back pain. Nervous system disorders: Dizziness, headache, hyper/hypoaesthesia. Psychiatric disorders: Depression, nightmare, anxiety. Renal and urinary disorders: Dysuria, nocturia. Reproductive system and breast disorders: Impotence. Respiratory, thoracic and mediastinal disorders: Dyspnoea, pharyngitis, wheezing. Skin and subcutaneous tissue disorders: Rash, pruritus. Vascular disorders: Hypotension.
This drug may cause dizziness, and fatigue, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor blood pressure and heart rate (at baseline, after the initial dose and after any dose adjustment); ECG; serum glucose (in diabetic patients); mental alertness. Monitor for signs and symptoms of bronchospasm in patients with bronchospastic disease.
Overdosage
Symptoms: Excessive bradycardia, hypotension, cardiogenic shock, advanced AV block, intraventricular conduction defects, severe CHF, pulmonary oedema, depressed level of consciousness, seizures, hypoglycaemia, bronchospasm, and, rarely, hyperkalaemia. Management: Perform gastric lavage or induce emesis. Administer IV atropine sulfate (1-3 mg in divided doses) without delay in case of excessive bradycardia or hypotension; if insufficient, administer slow IV isoprenaline (5 mcg/min) with constant monitoring until a response is achieved. For severe cases with circulatory collapse unresponsive to atropine and catecholamines, may give IV glucagon (10-20 mg). Employ cardiac pacing if bradycardia becomes severe. Consider cautious use of vasopressors, diazepam, phenytoin, lidocaine, digoxin, and bronchodilators depending on patient's condition.
Drug Interactions
Concomitant use with class I anti-arrhythmic agents (e.g. disopyramide) and amiodarone may increase atrial conduction time and induce negative inotropic effects. May diminish the effect of glibenclamide. May antagonise the effect of sympathomimetic and xanthine bronchodilators. May induce serious bradycardia with digoxin. Diminished antihypertensive effects with NSAIDs. Enhanced hypotensive effects with TCAs, barbiturates, phenothiazines, catecholamine-depleting agents (e.g. reserpine), and other antihypertensive agents. Enhanced bradycardic effects with fingolimod. Increased risk of cardiodepression with diltiazem.
Lab Interference
May result in false-positive aldosterone/renin ratio.
Action
Description: Mechanism of Action: Acebutolol is a cardioselective β-blocker that acts on the β1-adrenergic receptors in the heart with little or no effect on β2-receptors (except at high doses). It exhibits mild intrinsic sympathomimetic activity and membrane stabilising properties. Onset: 1-2 hours. Duration: 12-24 hours. Pharmacokinetics: Absorption: Well absorbed from the gastrointestinal tract. Bioavailability: Approx 40% (acebutolol). Time to peak plasma concentrations: 2-4 hours. Distribution: Widely distributed in the body. Crosses the placenta and enters breast milk. Volume of distribution: 1.2 L/kg. Plasma protein binding: Approx 26%. Metabolism: Undergoes extensive first-pass metabolism in the liver to equipotent and cardioselective diacetolol metabolite. Excretion: Via faeces (50-60%); urine (30-40%, mainly as diacetolol). Elimination half-life: 3-4 hours (acebutolol); 8-13 hours (diacetolol).
Chemical Structure
Storage
Store between 20-25°C. Protect from light and moisture.