Muscle relaxant that can be used in a patient with high serum bilirubin of 6.0 and serum creatinine of 4.5 mg/ dL?
Ans. a. Atracurium (Ref: Goodman Gilman 12/e p264; Morgan 4/e p221; Lee 13/e p191,192)Muscle relaxant that can be used in a patient with high serum bilirubin of 6.0 and serum creatinine of 4.5 mg/dL is Atracurium because of unique metabolism independent of hepatic and renal functions and ensured degradation.AtracuriumAvailable as atracurium besylateQTo be stored at 4degCQPharmacokinetics:Acidic compound, can precipitate if given in IV line containing alkaline solution like thiopentoneQ.Dose: 0.5 mg/kgQOnset of action: 2-3 minutes; Duration of action; 10-15 minutesQMetabolism of AtracuriumIt has unique method of degradationQ.It's metabolism is independent of hepatic and renal functionsQ.It undergoes spontaneous degradation in plasma called as Hoffman degradationQ.Systemic Effects:Histamine release is much less than d-tubocurare.CVS: Can cause bronchospasm because of release of histamine.CNS: At higher doses its metabolic product laudanosine can cross blood brain barrier and produce convulsions.Allergic reactions ranging from pruritic rash to angioneurotic edema can occur.Atracurium is relaxant of choice in (Because of unique metabolism independent of hepatic and renal functions and ensured degradation)Hepatic failureRenal failureQIf reversal agent is contraindicatedQMyasthenia gravisQNewbornQOld ageQCis-AtracuriumIt is an isomer of atracurium, 4 times more potentChief advantage of Cis-Atracurium over atracuriumIt does not release histamineQLaudanosine production is 5 times lesser than atracuriumQ.Whenever available it is always preferred over atracuriumQ.Important Muscle RelaxantsShortest and fastest acting neuromuscular blockerSuccinylcholineQShortest acting competitive (non-depolarizing) neuromuscular blockerMivacuriumQFastest acting non-depolarizing neuromuscular blockerRocuroniumQLongest acting and most potent non-depolarizing neuromuscular blockerDoxacuriumMaximum ganglion blockaded-TC
Atracurium
Vecuronium
Pancuronium
Mivacurium
Non-depolarising Neuromuscular Blocking Agents