Tracrium Drug Interactions

The neuromuscular block produced by Tracrium may be increased by the concomitant use of inhalation anaesthetics eg, halothane, isoflurane and enflurane.
In common with all non-depolarising neuromuscular blocking agents, the magnitude and/or duration of a non-depolarising neuromuscular block may be increased as a result of interaction with: antibiotics (including the aminoglycosides, polymyxins, spectinomycin, tetracyclines, lincomycin and clindamycin); antiarrhythmic drugs (propranolol, calcium-channel blockers, lignocaine, procainamide and quinidine); diuretics (furosemide and possibly mannitol, thiazide diuretics and acetazolamide); magnesium sulphate; ketamine; lithium salts; ganglion blocking agents (trimetaphan, hexamethonium).
Rarely, certain drugs may aggravate or unmask latent myasthenia gravis or actually induce a myasthenic syndrome; increased sensitivity to Tracrium would be consequent on such a development. Such drugs include various antibiotics, β-blockers (propranolol, oxprenolol), anti-arrhythmic drugs (procainamide, quinidine), anti-rheumatic drugs (chloroquine, D-penicillamine), trimetaphan, chlorpromazine, steroids, phenytoin and lithium.
The onset of non-depolarising neuromuscular block is likely to be lengthened and the duration of block shortened in patients receiving chronic anticonvulsant therapy.
The administration of combinations of non-depolarising neuromuscular blocking agents in conjunction with Tracrium may produce a degree of neuromuscular blockade in excess of that which might be expected were an equipotent total dose of Tracrium administered. Any synergistic effect may vary between different drug combinations.
A depolarising muscle relaxant eg, suxamethonium chloride should not be administered to prolong the neuromuscular blocking effects of non-depolarising agents eg, Tracrium, as this may result in a prolonged and complex block which can be difficult to reverse with anticholinesterase drugs.
Treatment with anticholinesterases, commonly used in the treatment of Alzheimer’s disease eg, donepezil, may shorten the duration and diminish the magnitude of neuromuscular blockade with atracurium.