Cis-atracurium is preferred over atracurium due to advantage of:
Ans. c. No histamine release Unlike atracurium, cisatracurium is devoid of dose dependent histamine releasing effect and therefore is associated with greater cardiovascular stability.AtracuriumCisatracurium* Atracurium besylate is a synthetic bisquaternary benzylisoquinolinium nondepolarizing neuromuscular blocking drug (ND-NMBD).* It is a mixture of 10 optical isomers.* Cisatracurium is benzylisoquinolinium NDNMBD.* Cisatracurium is 1R cis-1' R cis isomer of atracurium.* Atracurium contains -15% cisatracurium.* Less potent* 4 times more potent than atracurium* Slower onset and longer duration of action* Metabolized by organ independent spontaneous degradation by Hofmann elimination (45%) and esterhydrolysis (by non specific esterases not acetylcholinesterase or pseudocholinesterase). Both accounting for 60-90% metabolism.* 10-40% of total clearance occur via other pathways, presumably by metabolism or excretion by kidney or liver.* More cisatracurium is metabolized by Hofmann degradation (-77%).* In contrast, however there is no ester hydrolysis.* 23% of drug is eliminated through organ dependent means with renal elimination accounting for 16%* 4-5 times more laudanosine is produced(r).* Because of 4-5 times greater potency. 4-5 times lesser metabolites (laudanosine and mono quaternary acrylate) are produced.* Atracurium triggers dose dependent histamine release that becomes significant at doses > 0.5 mg/kg giving transient hypotension and tachycardia associated with facial and truncal flushing.* Atracurium may also cause a transient drop in systemic vascular resistance and an increase in cardiac index independent of any histamine release, which can be minimized by slow rate of injection.* Cisatracurium is devoid of histamine releasing effects, associated with greater cardiovascular stability. It does not affect heart rate or BP, nor does it produce autonomic effects even at rapid and large IV doses.
Rapid onset
Short duration of action
No histamine release
Less cardio depressant
Non-depolarising Neuromuscular Blocking Agents