Sotalol is used to suppress and prevent the recurrence of documented life-threatening ventricular arrhythmias (e.g., sustained ventricular tachycardia) and to maintain normal sinus rhythm in patients with symptomatic atrial fibrillation or flutter who are currently in sinus rhythm. Some experts state that sotalol may be used for the treatment of monomorphic ventricular tachycardia or preexcited atrial arrhythmias (associated with an accessory pathway).
The choice of a β-adrenergic blocking agent depends on numerous factors, including pharmacologic properties (e.g., relative β-selectivity, intrinsic sympathomimetic activity, membrane-stabilizing activity, lipophilicity), pharmacokinetics, intended use, and adverse effect profile, as well as the patient's coexisting disease states or conditions, response, and tolerance. While specific pharmacologic properties and other factors may appropriately influence the choice of a β-blocker in individual patients, evidence of clinically important differences among the agents in terms of overall efficacy and/or safety is limited. Patients who do not respond to or cannot tolerate one β-blocker may be successfully treated with a different agent.
Sotalol is used to suppress and prevent the recurrence of documented life-threatening ventricular arrhythmias (e.g., sustained ventricular tachycardia) and is designated an orphan drug by the FDA for such use.
It remains to be established whether antiarrhythmic agents, including sotalol, have a beneficial effect on mortality or sudden death. Findings from the National Heart, Lung, and Blood Institute (NHLBI)'s Cardiac Arrhythmia Suppression Trial (CAST) after an average of 10 months of follow-up have indicated that the rate of total mortality and nonfatal cardiac arrest in patients with recent myocardial infarction, mild to moderate left ventricular dysfunction, and asymptomatic or mildly symptomatic ventricular arrhythmias (principally frequent ventricular premature complexes [VPC]) who received encainide or flecainide (class I antiarrhythmic drugs) increased substantially compared with placebo. Therefore, the FDA and some experts recommend that use of class I antiarrhythmic drugs in patients with ventricular arrhythmias be limited to those with life-threatening arrhythmias. It has been suggested that the applicability of these results from class I antiarrhythmic agents to predominantly class III antiarrhythmic agents, such as sotalol, a drug that is devoid of class I effects, is uncertain. Like other antiarrhythmic agents, sotalol can worsen existing arrhythmias or cause new arrhythmias, including torsades de pointes. Because of the drug's arrhythmogenic potential, use of sotalol for less severe arrhythmias, even if symptomatic, is not recommended by the manufacturer, and treatment of asymptomatic VPCs should be avoided.
The manufacturers recommend that sotalol therapy and subsequent dosage increases be initiated in an institutional setting. In addition, before progressing to chronic therapy, suitable (e.g., programmed electrical stimulation [PES], Holter) monitoring should be employed to evaluate potential antiarrhythmic efficacy.
Life-threatening Ventricular Arrhythmias and Advanced Cardiovascular Life Support
Antiarrhythmic drugs are used during cardiac arrest to facilitate and maintain a spontaneous perfusing rhythm in patients with refractory (i.e., persisting or recurring after at least one shock) ventricular fibrillation or pulseless ventricular tachycardia; however, there is no evidence that these drugs increase survival to hospital discharge when given routinely during cardiac arrest. High-quality cardiopulmonary resuscitation (CPR) and defibrillation are integral components of advanced cardiovascular life support (ACLS) and the only proven interventions to increase survival to hospital discharge. Other resuscitative efforts, including drug therapy, are considered secondary and should be performed without compromising the quality and timely delivery of chest compressions and defibrillation. The principal goal of pharmacologic therapy during cardiac arrest is to facilitate return of spontaneous circulation (ROSC), and epinephrine is considered the drug of choice for this use. Antiarrhythmic drugs may be considered for the treatment of refractory ventricular fibrillation or pulseless ventricular tachycardia during cardiac resuscitation; however, experts generally recommend the use of amiodarone (or lidocaine). IV sotalol may be used for the management of regular wide-complex tachycardias during the periarrest period and is included as a recommended antiarrhythmic agent in current ACLS guidelines for adult tachycardia.
Although comparative data are limited, oral or IV sotalol generally is considered to be as effective as some other antiarrhythmic agents (e.g., procainamide, quinidine) for the management of severe refractory arrhythmias. Data from clinical studies indicate that the drug is effective in approximately 55-85% of patients with life-threatening ventricular arrhythmias, including those refractory to other antiarrhythmic agents. Sotalol can reduce VPCs, paired VPCs, and nonsustained ventricular tachycardia in patients with frequent VPCs and can suppress the recurrence of ventricular tachyarrhythmias in patients with ventricular tachycardia and/or fibrillation. The drug also has suppressed Holter monitor evidence of sustained ventricular tachycardia and ventricular tachycardia induced by PES. Although sotalol has been reported to reduce the risk of death from any cause and from cardiac causes compared with several class I antiarrhythmics (e.g., mexiletine, procainamide, propafenone, quinidine) in patients with ventricular tachyarrhythmias, the drug has not been shown to have a benefit in terms of long-term survival or neurologic outcome.
Sotalol may be used for the treatment of hemodynamically stable patients with monomorphic ventricular tachycardia. Although rare, episodes of sustained polymorphic ventricular tachycardia (electrical storm) that are associated with acute myocardial infarction and are refractory to initial antiarrhythmic drug therapy (e.g., lidocaine, procainamide) should be managed by aggressive attempts at reducing myocardial ischemia, including therapies such as an IV β-adrenergic blocking agent, intra-aortic balloon counterpulsation, and/or emergency revascularization (percutaneous transluminal coronary angioplasty [PTCA], coronary artery bypass graft [CABG] surgery); IV amiodarone also may be useful.
Sotalol appears to be effective in the suppression and prevention of various supraventricular tachycardias (SVTs), including atrial fibrillation or flutter and paroxysmal supraventricular tachycardia (PSVT). Because of a higher risk of toxicity and proarrhythmic effects, antiarrhythmic agents such as sotalol generally should be reserved for patients who do not respond to or cannot be treated with AV nodal blocking agents (β-adrenergic blocking agents and nondihydropyridine calcium-channel blocking agents).
Atrial Fibrillation and Flutter
Oral sotalol is used in maintaining normal sinus rhythm in patients with symptomatic atrial fibrillation or flutter who are currently in sinus rhythm. Some experts state that sotalol may be used in patients with preexcited atrial arrhythmias. However, synchronized cardioversion is the intervention of choice. Because selected class III antiarrhythmic agents have the potential to cause life-threatening ventricular arrhythmias, the manufacturer states that sotalol should be reserved for the treatment of highly symptomatic atrial fibrillation.
(See Cautions: Arrhythmogenic Effects.)In addition, patients with paroxysmal atrial fibrillation that is easily reversed (e.g., by the Valsalva maneuver) should not receive sotalol. If atrial fibrillation has been present for more than 48 hours, a risk of systemic embolization exists with conversion to sinus rhythm unless the patient is adequately anticoagulated.
Available data suggest that the efficacy of oral sotalol for prevention of recurrences of atrial fibrillation or flutter is comparable to that of quinidine or propafenone and less than that of amiodarone. Maintenance of sinus rhythm with oral sotalol does not appear to be related to either duration of previous episodes of atrial fibrillation (e.g., paroxysmal or persistent atrial fibrillation) or the degree of atrial enlargement.
Other Supraventricular Tachycardias
Sotalol also has been used in patients with other SVTs, including paroxysmal supraventricular tachycardia (PSVT) due to AV nodal reentry tachycardia (AVNRT) or AV reentry tachycardia (AVRT). However, many experts prefer vagal maneuvers and IV adenosine as initial therapeutic choices for the treatment of PSVT in patients without contraindications to these therapies. Sotalol may be a reasonable choice of therapy for the ongoing management of patients with symptomatic SVT who are not candidates for, or prefer not to undergo, catheter ablation and in whom first-line drugs (e.g., β-adrenergic blocking agents, diltiazem, verapamil) are not effective or are contraindicated.