Drug Interactions between fingolimod and procainamide

CONTRAINDICATED: Theoretical concerns exist that initiating treatment with fingolimod may potentiate the risk of torsade de pointes arrhythmia associated with the use of class IA (e.g., disopyramide, quinidine, procainamide) and class III (e.g., amiodarone, dofetilide, ibutilide, sotalol) antiarrhythmic agents. Fingolimod can cause a decrease in heart rate during initiation of therapy that is apparent within an hour of the first dose and maximal at approximately 6 hours postdose in most cases, but occasionally up to 20 hours after the first dose. Further, but smaller decreases in heart rate may occur after the second dose, although heart rate eventually returns to baseline within one month of chronic treatment. The mean decrease in heart rate in patients receiving fingolimod 0.5 mg at 6 hours after the first dose was approximately 13 beats per minute (bpm). Heart rates below 40 bpm were rarely observed. In controlled clinical trials, adverse reactions of symptomatic bradycardia (hypotension, dizziness, fatigue, palpitations, chest pain) following the first dose were reported in 0.5% of patients receiving fingolimod 0.5 mg, compared to no patient on placebo. Initiation of fingolimod treatment has also resulted in transient AV conduction delays. First- and second-degree AV block (prolonged PR interval on ECG) following the first dose were each reported in 0.1% of patients receiving fingolimod 0.5 mg, compared to no patient on placebo. In a study of 698 patients with available 24-hour Holter monitoring data after their first dose, second degree AV blocks, usually Mobitz type I (Wenckebach), were reported in 3.7% of patients receiving fingolimod 0.5 mg and 2% of patients receiving placebo. Bradycardia and conduction abnormalities were usually transient and asymptomatic, and resolved within the first 24 hours on treatment, but they occasionally required treatment with atropine or isoproterenol.

MANAGEMENT: The use of fingolimod in patients with arrhythmias requiring treatment with class IA or class III antiarrhythmic agents has not been studied and is considered contraindicated.