IT BLOCKS INACTIVATED SODIUM CHANNELS. IT ALSO DECREASES CALCIUM CURRENT AND TRANSIENT OUTWARD,DELAYED RECTIFIER AND INWARD RECTIFIER POTASSIUM CURRENTS. IT IS POTENT INHIBITOR OF ABNORMAL AUTOMATICITY. IT PROLONGS DURATION OF ACTION POTENTIAL, REFACTORINESS IN PURKINJEE AND VENTRICULAR MUSCLE FIBRES. IT ALSO DECREASES CONDUCTION THROUGH AV NODE.REGULAR TESTS FOR THYROID , HEPATIC AND RENAL FUNCTIONS SHOULD BE DONE ROUTINELY.