Which is a safe muscle relaxant in renal failure ?

Ans. is 'a' i.e., Cisatracurium The unique feature of atracurium and cisatracurium is inactivation in plasma by spontaneous nonenzymatic degradation (Hofman elimination) in addition to that by alkaline ester hydrolysis. Therefore both of these do not require hepatic or renal routes for elimination therefore can be used safely in hepatic and renal failure. Moreover, cisatracurium does not provoke histamine release, therefore it is preferred over atracurium.