Sotalol and amiodarone: More alike than different in AF conversion?

CHICAGO – A newly published meta-analysis comparing the efficacy of antiarrhythmic drugs sotalol and amiodarone for the treatment of atrial fibrillation in two settings found no statistical difference between the two drugs in their ability to convert patients to normal sinus rhythm.

The findings, the author says, undermine a widely-held belief that amiodarone is the more effective option for conversion and should come as welcome news to doctors who mistakenly believe that greater efficacy is the trade for amiodarone’s considerable risk of side effects related to organ toxicity.

The analysis, Sotalol versus Amiodarone in Treatment of Atrial Fibrillation, is published in the February-March 2016 issue of the Journal of Atrial Fibrillation.

“What’s remarkable and what wasn’t known before … I and everyone else in the field thought that amiodarone was more effective in conversion,” said study author John C. Somberg M.D., a professor in the Department of Medicine & Pharmacology at Rush University. “It turns out they are about the same.”

Dr. Somberg, and co-author Janos Molnar M.D., undertook the meta-analysis to offer a useful comparison of the two drugs in light of the recent re-introduction of intravenous sotalol in the U.S. Somberg led the team that developed and secured the FDA approval of intravenous sotalol in 2009, but has since sold his proprietary interest.

Dr. Somberg said the results “clearly showed” that the two drugs are equivalent in efficacy. “Most physicians would have said that amiodarone is superior to sotalol in conversion. This study shows that it is not superior. They are clinically comparable.”

Methodology
Drs. Somberg and Molnar, of the American Institute of Therapeutics in Lake Bluff, IL, conducted a standard meta-analysis of published literature, analyzing the results of five studies that compared the two drugs for the conversion of atrial fibrillation to normal sinus rhythm and two studies that compared the drugs for maintenance of normal sinus rhythm following cardiac surgery. The included studies employed both intravenous and oral routes of administration for sotalol or amiodarone.

Results
The analysis found a “practically identical” efficacy between the two drugs for AF conversion and for the prevention of atrial fibrillation after cardiac surgery.

Sotalol was found to carry a higher risk of AF recurrence when long-term follow up was carried out. But while the review describes similar cardiac adverse events for the two drugs, amiodarone’s risk of serious non-cardiac side effects, including organ toxicity, requires serious consideration, the authors concluded.

“Given the similar efficacy of sotalol and amiodarone and the short and long term toxicity of amiodarone, consideration should be given to employing IV and oral sotalol in the treatment of AF in patients with adequate left ventricular function,” the authors write.

The authors noted the limitations of their review, including the relatively small number of studies used and the short follow up times.

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About AltaThera Pharmaceuticals: AltaThera Pharmaceuticals is a specialty pharmaceutical company focused on critical care and alternative therapeutics for the unmet medical needs of patients with severe, and often rare disorders for which few effective treatments are available. AltaThera is the manufacturer of Sotalol IV.  Sotalol IV carries a Boxed Warning related to life-threatening proarrhythmia.

Click here for Full Prescribing Information including Boxed Warning.

About Sotalol IV:

Sotalol IV, sotalol hydrochloride injection, 15 mg/mL for intravenous use is an antiarrhythmic agent indicated for substitution for oral sotalol in patients who are unable to take sotalol orally. Oral sotalol is indicated for maintenance of normal sinus rhythm in patients with history of highly symptomatic atrial fibrillation/flutter and treatment of documented life-threatening ventricular arrhythmias.

IMPORTANT SAFETY INFORMATION

WARNING: LIFE THREATENING PROARRHYTHMIA

Sotalol can cause life threatening ventricular tachycardia associated with QT interval prolongation. Do not initiate sotalol therapy if the baseline QTc is longer than 450 ms. If the QT interval prolongs to 500 ms or greater, the dose must be reduced, the duration of the infusion prolonged or the drug discontinued. Patient should be hospitalized in a facility that can provide cardiac resuscitation and continuous electrocardiographic monitoring. Adjust the dosing interval based on creatinine clearance.

For the safety of the patient, the safety measures required of oral sotalol administration must also be applied for intravenous route.

As the bioavailability of oral sotalol is between 90% and 100%, the corresponding dose of intravenous sotalol is slightly less than that of the oral dose. 75 mg of intravenous sotalol is approximately equal to 80 mg of oral sotalol. Monitor the effect of the initial intravenous dose and titrate either upward or downward, if needed, based on clinical effect, QT interval or adverse reactions. Sotalol is contraindicated in patients with sinus bradycardia (<50 bpm), sick sinus syndrome or second or third degree AV block unless a functioning pacemaker is present; in patients with congenital or acquired long QT syndromes, QT interval >450 ms; in patients with cardiogenic shock or uncontrolled heart failure; in patients with creatinine clearance <40 mL/min; in patients with serum potassium <4 meq/L; in patients with bronchial asthma or related bronchospastic conditions; and in patients with known hypersensitivity to sotalol.

Sotalol can cause serious ventricular arrhythmias, primarily Torsade de Pointes (TdP) type ventricular tachycardia. Factors such as reduced creatinine clearance, gender (female) and larger doses increase the risk of TdP. Calculation of the creatinine clearance must precede administration of the first dose of sotalol. The use of sotalol in conjunction with other drugs that prolong the QT interval has not been studied and is not recommended. Sotalol may increase bradycardia in patients with supraventricular arrhythmia. Bradycardia itself increases the risk of Torsades de Pointes. Patients receiving concomitant digoxin must be carefully monitored. Do not abruptly discontinue treatment. Occasional cases of exacerbation of angina pectoris, arrhythmias, and in some cases, myocardial infarction have been reported after abrupt discontinuation of beta-blocker therapy. Sotalol may increase the propensity to develop serious arrhythmias in patients with left ventricular dysfunction. Sotalol should not be used in patients with hypokalemia or hypomagnesemia prior to correction of imbalance, as these conditions increase the potential for Torsades de Pointes. Special attention should be given to electrolyte and acid based balance in patients experiencing severe or prolonged diarrhea or patients receiving concomitant diuretic drugs. Monitor serum glucose in diabetic patients as sotalol, like all beta-blockers in general, may mask symptoms of hypoglycemia or worsen hyperglycemia.

There is no clinical experience with intravenous sotalol. Because of the similarity in exposure between intravenous sotalol and oral sotalol, adverse reactions should be similar. The most common adverse reactions (>10%) seen with oral sotalol (dose related) are fatigue, dizziness, lightheadedness, headache, asthenia, nausea, dyspnea, bradycardia, chest pain and palpitation.

Please see Full Prescribing Information including Boxed Warning.

Contact:
Patricia Dunnigan
Manager, Communications & Marketing
AltaThera Pharmaceuticals
200 S. Wacker Drive
Suite 3100
Chicago, IL 60606





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