Increases neuromuscular blockade with volatile anaesthetic agents (halothane, ether, enflurane, isoflurane, methoxyflurane, propofol and cyclopropane), fentanyl, other non-depolarising muscle relaxants, prior admin of succinylcholine, tetracyclines, polymyxins, diuretics, thiamine, MAOIs, bacitracin, colistin, sodium colistimethate, acylaminopenicillins, aminoglycoside antibiotics, high dose metronidazole, protamine, beta-adrenergic blocking agents, calcium antagonists e.g. verapamil, and Mg. Decreased neuromuscular blockade with anticholinesterases, prior chronic admin of corticosteroids, phenytoin, carbamazepine, noradrenaline, azathioprine, theophylline, calcium chloride.