sotalol
Betapace, Betapace AF

Available forms
Available by prescription only
Betapace
Tablets: 80 mg, 120 mg, 160 mg, 240 mg
Betapace AF
Tablets: 80 mg, 120 mg, 160 mg

Indications and dosages
 Documented, life-threatening ventricular arrhythmias. Betapace. Adults: Initially, 80 mg P.O. b.i.d. Increase dose q 2 to 3 days as needed and tolerated. Most patients respond to daily dose of 160 to 320 mg given in divided doses b.i.d. A few patients with refractory arrhythmias have received as much as 640 mg daily given in divided doses b.i.d.
≡ Dosage adjustment. For adults with renal impairment and creatinine clearance above 60 ml/ minute, no adjustment in dose interval is needed. If creatinine clearance is 30 to 60 ml/minute, give q 24 hours; if 10 to 29 ml/minute, q 36 to 48 hours; if less than 10 ml/minute, individualized dosage.
 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. Betapace AF. Adults: Initially, 80 mg P.O. b.i.d. If initial dose doesn’t reduce frequency of relapses of AFIB/AFL and is tolerated without excessive QTc- interval prolongation (520 msec or more), dosage level may be increased after 3 days to 120 mg P.O. b.i.d. Maximum dose is 160 mg P.O. b.i.d.
≡ Dosage adjustment. For patients with creatinine clearance of 40 to 60 ml/minute, give one daily dose. Don’t give to patients whose creatinine clearance is less than 40 ml/minute.

Pharmacodynamics
Antiarrhythmic action: Sotalol is a nonselective beta blocker that depresses sinus heart rate, slows AV conduction, increases AV nodal refractoriness, prolongs the refractory period of atrial and ventricular muscle and AV accessory pathways in anterograde and retrograde directions, decreases cardiac output, and lowers systolic and diastolic blood pressure.

Pharmacokinetics
Absorption: Well absorbed after oral administration, with a bioavailability of 90% to 100%. After oral administration, steady state plasma levels are attained in 2 to 3 days (after five to six doses when given twice daily).
Distribution: Doesn’t bind to plasma proteins and crosses the blood-brain barrier poorly.
Metabolism: Not metabolized.
Excretion: Excreted primarily in urine unchanged.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug and in those with severe sinus node dysfunction, sinus bradycardia, second- and third-degree AV block in the absence of an artificial pacemaker, congenital or acquired long QT syndrome, cardiogenic shock, uncontrolled heart failure, and bronchial asthma. Betapace AF is contraindicated in patients with creatinine clearance below 40 ml/minute.
  Use cautiously in patients with impaired renal function or diabetes mellitus.

Interactions
Drug-drug. Antacids: Decreases effects of sotalol. Advise patient to take 2 hours apart.
Antiarrhythmics: Causes additive effects when administered with sotalol. Avoid use together.
Calcium channel blockers: Enhances myocardial depression. Don’t give with sotalol.
Catecholamine-depleting drugs, such as guanethidine and reserpine: Enhances hypotensive effects of sotalol. Monitor patient closely.
Clonidine: Sotalol may enhance the rebound hypertensive effect after withdrawal of clonidine. Discontinue sotalol several days before withdrawing clonidine.
Insulin, oral antidiabetics: Increases blood glucose levels and possibly masks symptoms of hypoglycemia. Adjust sotalol dosage if needed.
Drug-food. Any food: Decreases absorption. Tell patient to take drug on an empty stomach.

Adverse reactions
CNS: asthenia, light-headedness, headache, dizziness, weakness, fatigue, sleep problems.
CV: bradycardia, palpitations, chest pain, arrhythmias, heart failure, AV block, proarrhythmic events (ventricular tachycardia, PVCs, ventricular fibrillation), edema, ECG abnormalities, hypotension.
GI: nausea, vomiting, diarrhea, dyspepsia.
Metabolic: hyperglycemia.
Respiratory: dyspnea, bronchospasm.

Effects on lab test results
• May increase glucose and liver enzyme levels.

Overdose and treatment
The most common signs and symptoms of overdose are bradycardia, heart failure, hypotension, bronchospasm, and hypoglycemia.
 If overdose occurs, discontinue sotalol. Because of the lack of protein-binding, hemodialysis is useful in reducing sotalol plasma levels. Observe patient carefully until QT intervals are normalized. Atropine, another anticholinergic drug, a beta-adrenergic agonist, or transvenous cardiac pacing also may be used to treat bradycardia; transvenous cardiac pacing to treat second- or third-degree heart block; epinephrine to treat hypotension (depending on associated factors); aminophylline or an aerosol beta₂-receptor stimulant to treat bronchospasm; and DC cardioversion, transvenous cardiac pacing, epinephrine, or magnesium sulfate to treat torsades de pointes.

Special considerations
 ALERT Don’t substitute Betapace for Betapace AF.
• Because proarrhythmic events, such as sustained ventricular tachycardia or ventricular fibrillation, may occur when therapy starts or dosage is adjusted, patient should be hospitalized. Facilities and personnel should be available for cardiac rhythm monitoring and ECG interpretation.
• Although patients receiving I.V. lidocaine have begun sotalol therapy without ill effect, other antiarrhythmics should be withdrawn before sotalol therapy begins. Sotalol therapy typically is delayed until two or three half-lives of the withdrawn drug have elapsed. After withdrawal of amiodarone, sotalol shouldn’t be given until the QT interval normalizes.
• Monitor serum electrolyte levels regularly, especially if patient is receiving diuretics. Electrolyte imbalances, such as hypokalemia or hypomagnesemia, may enhance QT interval prolongation and increase risk of serious arrhythmias, such as torsades de pointes.
Betapace AF
• Patients with a history of symptomatic atrial fibrillation or flutter who are currently taking Betapace to maintain a normal sinus rhythm should be switched to Betapace AF because of significant differences in labeling between drugs.
• Anticoagulate patients who have atrial fibrillation according to standard practice.
• Adjust dosage slowly, allowing 3 days (or five to six doses if patient is receiving once-daily doses) between dose increments for adequate monitoring of QT intervals and for drug plasma levels to reach steady state.
• The baseline QTc interval must be 450 msec or less in order to initiate Betapace AF therapy. During initiation and dosage adjustment, monitor QTcinterval 2 to 4 hours after each dose. If QTc interval is 500 msec or more, reduce dose or discontinue drug.
Pregnant patients
• Safety hasn’t been established. Use only when potential benefits outweigh the risks to the fetus.
Breast-feeding patients
• Drug may appear in breast milk. Either breast-feeding or sotalol may be discontinued depending on importance of drug to mother.
Pediatric patients
• Safety and efficacy in children haven’t been established.

Patient education
• Explain importance of taking sotalol as prescribed, even when feeling well.
• Caution patient not to stop drug suddenly.
• Tell patient not to take antacids within 2 hours of sotalol.
• Tell patient not to double the next dose if he misses one. Instead, tell him to take the next dose at the usual time.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use