Adult: Life-threatening cases: Initially, 5 mg/kg as rapid IV inj, may increase to 10 mg/kg and repeat at 15-30 min intervals if arrhythmia persists. Max: 30 mg/kg. Other ventricular arrhythmias: 5-10 mg/kg by IM or IV inj over >8 min, may repeat in 1-2 hr if arrhythmia persists. Maintenance: IM: 5-10 mg/kg 6-8 hrly. IV: 5-10 mg/kg over >8 min 6 hrly as intermittent infusion or 1-2 mg/min as continuous infusion.