Sectral (Acebutolol Hydrochloride) - Drug Interactions, Contraindications, Overdosage, etc

Drug Interactions:

Catecholamine-depleting drugs, such as reserpine, may have an additive effect when given with β-blocking agents. Patients treated with Sectral plus catecholamine depletors should, therefore, be observed closely for evidence of marked bradycardia or hypotension which may present as vertigo, syncope/presyncope, or orthostatic changes in blood pressure without compensatory tachycardia. Exaggerated hypertensive responses have been reported from the combined use of β-adrenergic antagonists and α-adrenergic stimulants, including those contained in proprietary cold remedies and vasoconstrictive nasal drops. Patients receiving β-blockers should be warned of this potential hazard.

Blunting of the antihypertensive effect of beta-adrenoceptor blocking agents by nonsteroidal anti-inflammatory drugs has been reported.

No significant interactions with digoxin, hydrochlorothiazide, hydralazine, sulfinpyrazone, oral contraceptives, tolbutamide, or warfarin have been observed.

Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia.

OVERDOSAGE

No specific information on emergency treatment of overdosage is available for Sectral. However, overdosage with other β-blocking agents has been accompanied by extreme bradycardia, advanced atrioventricular block, intraventricular conduction defects, hypotension, severe congestive heart failure, seizures, and in susceptible patients, bronchospasm and hypoglycemia. Although specific information on the emergency treatment of Sectral overdose is not available, on the basis of the pharmacological actions and the observations in treating overdoses with other β-blockers, the following general measures should be considered:

1. Empty stomach by emesis or lavage.
2. Bradycardia: IV atropine (1 to 3 mg in divided doses). If antivagal response is inadequate, administer isoproterenol cautiously since larger than usual doses of isoproterenol may be required.
3. Persistent hypotension in spite of correction of bradycardia: Administer vasopressor (e.g., epinephrine, levarterenol, dopamine, or dobutamine) with frequent monitoring of blood pressure and pulse rate.
4. Bronchospasm: A theophylline derivative, such as aminophylline and/or parenteral β₂-stimulant, such as terbutaline.
5. Cardiac failure: Digitalize the patient and/or administer a diuretic. It has been reported that glucagon is useful in this situation.

Sectral is dialyzable.

CONTRAINDICATIONS

Sectral is contraindicated in: 1) persistently severe bradycardia; 2) second- and third-degree heart block; 3) overt cardiac failure; and 4) cardiogenic shock. (See WARNINGS.)