Atracurium is the muscle relaxant of choice in patients with liver and renal failure because these drugs undergo extensive plasma degradation. Atracurium undergoes esterase degradation and spontaneous breakdown at physiologic pH and temperature called Hoffman elimination. Metabolism of atracurim yields a metabolite called laudanosine, a renally cleared excitatory amine that can induce seizures. Atracurium, cisatracurium and mivacurium are non depolarizing neuromuscular blockers which can be used in patients with hepatic and renal failure. Ref: Critical Care Medicine : The Essentials By John J. Marini, Ahur P. Wheeler, Page 314; Medical Toxicology By Richard C. Da, Page 586