It is a class 1 antiarrhythmic drug (subgroup 1 C) Indications: paroxysmal supraventricular tachyarrhythmias including atrial flutter or fibrillation and re-entrant tachycardias; ventricular arrhythmias.

Cautions: pacemaker patients; pregnancy and breast- feeding; obstructive airway disease; heart failure; myasthenia gravis and in elderly.

Contra-indications: uncontrolled congestive heart failure, cardiogenic shock, and in severe electrolyte disturbances.

Side Effects: bradycardia and conduction disturbances; arrhythmias, nausea and vomiting, constipation; parasthesias, disturbances of vision and vertigo; rarely hypersensitivity reactions.

Dose: In patients with a body weight in excess of 70kg, initial dose 150 mg 3 times daily after food. The dose should be adjusted for patients weighing less than 70kg.