Anaphylactic Reactions on Muscle Relaxants

🔅Neuromuscular blocking agents (NMBAs) represent the most frequently incriminated substances for allergic reactions, among all drugs used in the perioperative period, ranging from 50 to 70% (1)

🔅Substances responsible for IgE-mediated anaphylaxis. Among NMBAs, the following substances have been incriminated, in decreasing order of importance: suxamethonium, vecuronium, atracurium, pancuronium, rocuronium, mivacurium and cisatracurium.(1)

🔅incidence of anaphylactic reactions are seen more with suxamethonium and rocuronium. (2) (3)

🔅These reactions are more severe than on latex 

🔅seem to occur more frequently in women than in men.

🔅if rapid-sequence induction is not mandatory, safer alternatives like cisatracurium can be used , in place of Rocuronium

🔅Regarding suxamethonium, more frequently it causes histamine release from mast cells and basophils, resulting in flushing and urticaria (without anaphylactic reactions)(4)

🔅Regarding atracurium , histamine release is observed in 40% of patients who receive doses over 0.5 mg/kg, resulting in transient hypotension and tachycardia; this can be prevented by injecting the drug slowly over 75 seconds, reducing the dose or prior treatment with 0.1 mg/kg chlorpheniramine and 2 mg/kg cimetidine i.v. (4)

🔅Cisatracurium will not cause histamine release in clinical dose range. Cisatracurium had the lowest rate of cross-reactivity in patients who had previously suffered anaphylaxis to rocuronium or vecuronium.(4)

🔅 Mivacurium causes transient fall in b.p. due to histamine release with doses above 0.2 mg/kg(4)

🔅The estimated sensitivity of skin tests for muscle relaxants is approximately 94 to 97 %. (1)

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Reference: 

(1) www.worldallergy.org , Allergy to Anesthetic Agents, Mertes Paul Michel, Demoly Pascal, Stenger Rodolphe , Updated May 2013 ,Originally posted: October 2007, Reviewed by: Mario Sánchez-Borges

(2)A. Gullo(Editor) Anaesthesia, Pain, Intensive Care and Emergency – A.P.I.C.E. 

(3) Proceedings of the 22 nd Postgraduate Course in Critical Care Medicine, Incidents Provoked Specifically by Certain Drugs Used in Anaesthesia M. K LIMEK , T.H. O TTENS ,F.G RÜNE

(4) Lee's Synopsis of Anaesthesia,13/e, p:191-193

(5) Br J Anaesth. 2013 Jun;110(6):981-7. Anaphylaxis to neuromuscular blocking drugs: incidence and cross-reactivity in Western Australia from 2002 to 2011., Sadleir PH1, Clarke RC, Bunning DL, Platt PR.