Azathioprine Atracurium

Azathioprine has been reported to reduce atracurium blockade transiently and to a clinically insignificant extent (50). 

Gramstad L. Atracurium, vecuronium and pancuronium in end-stage renal failure. Dose-response properties and interactions with azathioprine. Br J Anaesth 1987 59(8) 995-1003. 

There i limited evidence to surest that the neuromuscular blocking effects of atracurium, pancuronium and vecuronium may be increased in some patients taking ciclosporin. There is also some evidence of reduced neuromuscular blockade with aza-thioprine and antilymphocyde immunoglobulins, but other evidence suggests that there is no clinically relevant interaction with azathioprine. 

Direct information seems to be limited to the reports cited, and the interactions are not established. Although retrospective data suggest that aza-thioprine and antilymphocyte immunoglobulins can cause a reduction in the effects of neuromuscular blockers, and in some cases the dosage may need to be increased two- to fourfold, the only prospective study found that the interaction with azathioprine was not clinically significant. The general importance of the ciclosporin interaction is also uncertain, but be alert for an increase in the effects of atracurium, pancuronium or vecuronium in any patient receiving ciclosporin. Not all patients appear to develop this interaction. More study is needed. 

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