Acebutolol hydrochloride

Acebutolol hydrochloride
INN
Drug class
Routes of administration	Oral
Pregnancy category
Bioavailability	40%
Metabolism	Hepatic
Elimination half-life	3-4 hours
Excretion	Renal
Legal status
CAS Number	37517-30-9
PubChem	1977
DrugBank	DB01193
ChemSpider	1902
KEGG	D00219

Acebutolol hydrochloride is a beta-adrenergic blocking agent (beta-blocker) used primarily in the treatment of hypertension and cardiac arrhythmias. It is a selective beta-1 receptor antagonist with intrinsic sympathomimetic activity.

Pharmacology

Mechanism of Action

Acebutolol hydrochloride works by blocking beta-1 adrenergic receptors in the heart, which leads to a decrease in heart rate, cardiac output, and blood pressure. This action helps to reduce the workload on the heart and is beneficial in conditions such as hypertension and arrhythmias. Unlike non-selective beta-blockers, acebutolol has a lower risk of causing bronchoconstriction, making it more suitable for patients with asthma or chronic obstructive pulmonary disease (COPD).

Pharmacokinetics

Acebutolol is well absorbed from the gastrointestinal tract, but it undergoes significant first-pass metabolism in the liver, resulting in a bioavailability of approximately 40%. The drug is metabolized to an active metabolite, diacetolol, which contributes to its therapeutic effects. Acebutolol and its metabolites are primarily excreted by the kidneys. The elimination half-life of acebutolol is approximately 3 to 4 hours, while diacetolol has a longer half-life of about 8 to 12 hours.

Clinical Uses

Hypertension

Acebutolol is used in the management of hypertension, either alone or in combination with other antihypertensive agents. By reducing heart rate and cardiac output, it helps to lower blood pressure and reduce the risk of complications associated with high blood pressure, such as stroke and myocardial infarction.

Cardiac Arrhythmias

Acebutolol is effective in the treatment of certain types of cardiac arrhythmias, including ventricular premature beats and supraventricular tachycardia. Its ability to stabilize cardiac rhythm makes it a valuable option in managing these conditions.

Adverse Effects

Common adverse effects of acebutolol include fatigue, dizziness, headache, and gastrointestinal disturbances such as nausea and diarrhea. Due to its beta-blocking activity, it may also cause bradycardia and hypotension. Patients with a history of heart failure should use acebutolol with caution, as it can exacerbate symptoms.

Contraindications

Acebutolol is contraindicated in patients with severe bradycardia, second- or third-degree heart block, cardiogenic shock, and overt cardiac failure. It should be used with caution in patients with diabetes mellitus, as it can mask the symptoms of hypoglycemia.

Drug Interactions

Acebutolol may interact with other medications, including other antihypertensive agents, which can potentiate its blood pressure-lowering effects. Caution is advised when used with calcium channel blockers such as verapamil and diltiazem, as this combination can lead to excessive cardiac depression.

Special Populations

Pregnancy and Lactation

Acebutolol is classified as pregnancy category B in the United States, indicating that there is no evidence of harm to the fetus in animal studies, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed. Acebutolol is excreted in breast milk, and caution is advised when administering to nursing mothers.

Pediatric and Geriatric Use

The safety and efficacy of acebutolol in pediatric patients have not been established. In geriatric patients, dose adjustments may be necessary due to the increased risk of adverse effects and altered pharmacokinetics.

Conclusion

Acebutolol hydrochloride is a valuable medication in the management of hypertension and cardiac arrhythmias, offering the benefits of beta-1 selectivity and intrinsic sympathomimetic activity. Its use should be carefully considered in patients with contraindications and potential drug interactions.