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Active ingredient: Sotalol - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

  • Adrenergic beta-Antagonists
  • Anti-Arrhythmia Agents
  • Sympatholytics

Dosage Forms

  • Tablets (white, capsule-shaped, for oral administration)

Brands / Synonyms

Betapace; Betapace AF; Sorine; Sotalol; Sotalol HCL

Indications

For the maintenance of normal sinus rhythm [delay in time to recurrence of atrial fibrillation/atrial flutter (AFIB/AFL)] in patients with symptomatic AFIB/AFL who are currently in sinus rhythm. Also for the treatment of documented life-threatening ventricular arrhythmias.

Pharmacology

Sotalol is an antiarrhythmic drug. It falls into the class of beta blockers (and class II antiarrhythmic agents) because of its primary action on the β-adrenergic receptors in the heart. In addition to its actions on the beta receptors in the heart, sotalol inhibits the inward potassium ion channels of the heart. In so doing, sotalol prolongs repolarization, therefore lengthening the QT interval and decreasing automaticity. It also slows atrioventricular (AV) nodal conduction. Because of these actions on the cardiac action potential, it is also considered a class III antiarrhythmic agent. The beta-blocking effect of sotalol is non-cardioselective, half maximal at about 80mg/day and maximal at doses between 320 and 640 mg/day. Sotalol does not have partial agonist or membrane stabilizing activity. Although significant beta-blockade occurs at oral doses as low as 25 mg, significant Class Ieffects are seen only at daily doses of 160 mg and above.

Mechanism of Action

Sotalol has both beta-adrenoreceptor blocking (Vaughan Williams Class I) and cardiac action potential duration prolongation (Vaughan Williams Class I) antiarrhythmic properties. Sotalol is a racemic mixture of d- and l-sotalol. Both isomers have similar Class I antiarrhythmic effects, while the l-isomer is responsible for virtually all of the beta-blocking activity.

Absorption

In healthy subjects, the oral bioavailability of sotalol is 90-100%. Absorption is reduced by approximately 20% compared to fasting when administered with a standard meal.

Toxicity

The most common signs to be expected are bradycardia, congestive heart failure, hypotension, bronchospasm and hypoglycemia. In cases of massive intentional overdosage (2-16 grams) of sotalol the following clinical findings were seen: hypotension, bradycardia, cardiac asystole, prolongation of QT interval, Torsade de Pointes, ventricular tachy-cardia, and premature ventricular complexes.

Biotrnasformation / Drug Metabolism

Sotalol is not metabolized.

Contraindications

BETAPACE AF™ (sotalol hydrochloride) is contraindicated in patients with sinus bradycardia (<50 bpm during waking hours), sick sinus syndrome or second and third degree AV block (unless a functioning pacemaker is present), congenital or acquired long QT syndromes, baseline QT interval >450 msec, cardiogenic shock, uncontrolled heart failure, hypokalemia (<4 meq/L), creati-nine clearance <40 mL/min, bronchial asthma and previous evidence of hypersensitivity to sotalol.

Drug Interactions

Drugs undergoing CYP450 metabolism

Sotalol is primarily eliminated by renal excretion; therefore, drugs that are metabolized by CYP450 are not expected to alter the pharmacokinetics of sotalol.

Digoxin

Proarrhythmic events were more common in sotalol treated patients also receiving digoxin; it is not clear whether this represents an interaction or is related to the presence of CHF, a known risk factor for proarrhythmia, in the patients receiving digoxin.

Calcium blocking drugs

BETAPACE AF™ should be administered with caution in conjunction with calcium blocking drugs because of possible additive effects on atrioventricular conduction or ventricular function. Additionally, concomitant use of these drugs may have additive effects on blood pressure, possibly leading to hypotension.

Catecholamine-depleting agents

Concomitant use of catecholamine-depleting drugs, such as reserpine and guanethidine, with a beta-blocker may produce an excessive reduction of resting sympathetic nervous tone. Patients treated with BETAPACE AF™ plus a catecholamine depletor should therefore be closely monitored for evidence of hypotension and/or marked bradycardia which may produce syncope.

Insulin and oral antidiabetics

Hyperglycemia may occur, and the dosage of insulin or antidiabetic drugs may require adjustment. Symptoms of hypoglycemia may be masked.

Beta-2-receptor stimulants

Beta-agonists such as salbutamol, terbutaline and isoprenaline may have to be administered in increased dosages when used concomitantly with BETAPACE AF™.

Clonidine

Beta-blocking drugs may potentiate the rebound hypertension sometimes observed after discontinuation of clonidine; therefore, caution is advised when discontinuing clonidine in patients receiving BETAPACE AF™.

Other

No pharmacokinetic interactions were observed with hydrochlorothiazide or warfarin.

Antacids

Administration of BETAPACE AF™ within 2 hours of antacids containing aluminum oxide and magnesium hydroxide should be avoided because it may result in a reduction in Cmax and AUC of 26% and 20%, respectively and consequently in a 25% reduction in the bradycardic effect at rest. Administration of the antacid two hours after BETAPACEAF™ has no effect on the pharmacoki-netics or pharmacodynamics of sotalol.

Drug/Laboratory Test Interactions

The presence of sotalol in the urine may result in falsely elevated levels of urinary metanephrine when measured by fluorimetric or photometric methods. In screening patients suspected of having a pheochromocytoma and being treated with sotalol, a specific method, such as a high performance liquid chromato-graphic assay with solid phase extraction (e.g., J. Chromatogr. 385:241, 1987) should be employed in determining levels of catecholamines.

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