Mesylate hydrochloride tablets are mainly used for cardiac arrhythmia, the most common side effects of this drug are first of all gastrointestinal reactions, including nausea, vomiting, and abnormalities of liver function, such as the appearance of elevated aminotransferases. Secondly, patients may experience neurological side effects, such as dizziness, tremor, usually in the hands, ataxia, nystagmus, drowsiness, coma, diplopia, blurred vision and insomnia. In addition, patients may also experience cardiovascular side effects, such as tachycardia, hypotension and other symptoms. In addition, very few patients may experience a decrease in white blood cells or platelets. In conclusion, the most common side effects of this drug, mexiletine hydrochloride, are mainly gastrointestinal and neurological, and in general about 20-30% of patients may experience adverse reactions.