Pancuronium Azathioprine

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. 

Azathioprine reduces sensitivity to pancuronium in experimental animals, possibly as a result of phosphodiesterase inhibition, increasing transmitter release (SEDA-4, 87) (40), (SEDA-13,104). 

Electrolyte imbalance, and diseases that lead to electrolyte imbalance, such as adrenal cortical insufficiency, alter neuromuscular blockade. Depending on the nature of the imbalance, either enhancement or inhibition may be expected. Magnesium sulfate, used in the management of toxemia of pregnancy, enhances the skeletal-muscle-relaxing effects of pancuronium. Antibiotics such as aminoglycosides, tetracyclines, clindamycin, lincomycin, colistin, and sodium colistimethate augment the pancuronium-induced neuromuscular blockade. Anesthetics such as halothane, enflurane, and isoflurane enhance the action of pancuronium, whereas azathioprine will cause a reversal of neuromuscular blockade. 

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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