Mexiletine hydrochloride 50 mg, 100 mg, 200 mg Hard Capsules contain mexiletine and some patients taking mexiletine may develop cardiac arrhythmia which can be life-threatening. This Patient alert card provides important information to patients about their treatment and aims to raise awareness and inform healthcare providers and pharmacists about the ongoing medication the patient is taking and the risk of cardiac arrhythmia which can be life-threatening.