Sotalol, sold under the brand name Betapace among others, is a medication used to treat and prevent abnormal heart rhythms.

[1] Common side effects include a slow heart rate, chest pain, low blood pressure, feeling tired, dizziness, shortness of breath, problems seeing, vomiting, and swelling.

[8] Due to the risk of serious side effects, the FDA states that sotalol should generally be reserved for people whose ventricular arrhythmias are life-threatening, or whose fibrillation/flutter cannot be resolved using the Valsalva maneuver or another simple method.

[8] Sotalol has shown some potential efficacy against symptoms of essential tremor due to its binding to the β2-adrenergic receptor but this remains an off-label use.

[8] Studies have found serious side effects to be more common in individuals also taking digoxin, possibly because of pre-existing heart failure in those people.

[3] In rare cases, the QT prolongation caused by sotalol can lead to the development of life-threatening torsade de pointes (TdP) polymorphic ventricular tachycardia.

Across several clinical trials, 0.6% of oral sotalol patients with supraventricular abnormal heart rhythms (such as atrial fibrillation) developed TdP.

[3] For patients who had a history of sustained ventricular tachycardia (abnormal rhythm lasting more than 30 seconds), 4% developed TdP.

[16] By blocking these potassium channels, sotalol inhibits efflux of K+ ions, which results in an increase in the time before another electrical signal can be generated in ventricular myocytes.

[medical citation needed] Sotalol is classified as a beta blocker with low lipophilicity and hence lower potential for crossing the blood–brain barrier.