AND AIM OF WORK I Muscle relaxants made genefal anaesthesla more easy and effective, facilitated surgery and redued post-operative morbidity and m~rtality. Th~ir universal rola in control led ventilation has contributed to the remarkable improvement in the management and prognosis of diseases associated with respiratory failure, e.g. convulsions { tetanus, status epilepticus }, drug over dosage, head, chest injuries, and in the intensive care units. The ideal muscle relaxants should have the following properties:-(K~ and GL~, 1971) 1It should be competitive and non-depolarizing, thus side effects associated with depolarizers should not occur. 2The cessation of the neuromuscular blorkade should not depend on renal or hepatic function, so diseases of one or both of them do not impair its elimination. 3The breakdown products should not posses neuromuscular. blocking effects or other side effects. ~Relative rapid onset and short duration of action. 5Non cummulative effects, so when a large duration is desired, repeated or continous administration can be done.