Many drugs have been shown to influence the magnitude and/or duration of action of non-depolarising neuromuscular blocking agents, including the following.
Increased effect: Anaesthetics: volatile agents such as enflurane, isoflurane and halothane; ketamine; other non-depolarising neuromuscular blocking agents.
Other drugs: antibiotics: including the aminoglycosides, polymyxins, spectinomycin, tetracyclines, lincomycin and clindamycin; anti-arrhythmic drugs: including propranolol, calcium channel blockers, lidocaine, procainamide and quinidine; diuretics: including furosemide and possibly thiazides, mannitol and acetazolamide; magnesium salts; lithium salts; ganglion blocking drugs: trimetaphan, hexamethonium.
Rarely, certain drugs may aggravate or unmask latent myasthenia gravis or actually induce a myasthenic syndrome; increased sensitivity to non-depolarising neuromuscular blocking agents might result. Such drugs include various antibiotics, beta-blockers (propranolol, oxprenolol), anti-arrhythmic drugs (procainamide, quinidine), anti-rheumatic drugs (chloroquine, D-penicillamine), trimetaphan, chlorpromazine, steroids, phenytoin and lithium.
Administration of suxamethonium to prolong the effects of non-depolarising neuromuscular blocking agents may result in a prolonged and complex block which can be difficult to reverse with anticholinesterases.
Decreased effect: prior chronic administration of phenytoin or carbamazepine; treatment with anticholinesterases, commonly used in the treatment of Alzheimer's disease e.g. donepezil, may shorten the duration and diminish the magnitude of neuromuscular blockade with cisatracurium.
No effect: prior administration of suxamethonium has no effect on the duration of neuromuscular block following bolus doses of Cisatracurium (Nimbex) or on infusion rate requirements