Sotalol
Sotalol is a medication used to treat atrial fibrillation and ventricular tachycardia. It is considered a ‘beta blocker’ but has additional effects which help prevent arrhythmia.
The beta blocker effect of sotalol causes a reduction in heart rate, and slows electrical conduction through the heart. You will notice that your resting heart rate is a little lower on sotalol. If your heart goes out of rhythm, the slowing of electrical conduction will help to control the heart rate. But sotalol is principally prescribed to prevent atrial fibrillation or ventricular tachycardia.
Dosing
Sotalol is taken twice a day. Typically you will be started on 40mg or 80mg twice a day. It may be increased up to 160mg twice a day.
Side Effects
Sotalol has all of the usual ‘beta blocker’ possible side effects including fatigue, exercise intolerance, dizziness, and cold peripheries. Uncommonly it may cause depression.
It cannot be used if you have asthma.
Parodoxically, although sotalol is given to prevent rhythm abnormalities (like atrial fibrillation or ventricular tachycardia) there is a small risk that it can cause an arrhythmia called torsades de pointes - this is an abnormal rhythm that may cause fainting (syncope) and, in rare cases, cardiac arrest.
Monitoring
The risk of torsades de pointes is low if sotalol is monitored carefully. The risk is increased in heart failure, kidney disease, at doses above 320mg/day, at low heart rate, and with low potassium. It is also more common in females.
In my practice, all patients on sotalol will have an echocardiogram every 1-2 years to look for heart dysfunction, twice yearly kidney testing (EUC), and yearly ECG. This ECG can show a change called ‘QT prolongation’ which, if present, will mean you will have to stop the sotalol.
Summary:
With careful dose adjustment and monitoring, sotalol is a reasonable option to help suppress atrial fibrillation. However, there is a small risk even with this approach of causing a serious rhythm abnormality, perhaps around 1% over 5 years.