Antiepileptic-induced resistance to neuromuscular blockers: mechanisms and clinical significance.

Prolonged administration of antiepileptic drugs is associated with several drug interactions. In the field of anaesthesia and critical care, patients exhibit both sensitivity and resistance to non-depolarising neuromuscular blockers (NDNMBs) after acute and long-term administration of antiepileptic drugs, respectively. Although antiepileptic therapy alone has only mild neuromuscular effects, acutely administered antiepileptic drugs can potentiate the neuromuscular effects of NDNMBs as a result of direct pre- and post-junctional effects. Resistance to NDNMBs during long-term antiepileptic therapy is due to multiple factors operating alone or in combination, including induction of hepatic drug metabolism, increased protein binding of the NDNMBs and/or upregulation of acetylcholine receptors.