The action of muscle relaxants is affected by a variety of drugs. Ephedrine shortens onset time, while β-receptor blocker prolongs it. 1 Aminoglycoside antibiotics, 2 calcium channel blockers, and magnesium sulphate prolong duration, 3 , 4 whereas anticonvulsant drugs including carbamazepine shorten it. 5 Propitocaine, lidocaine, and other local anesthetics prolong duration, 6 while epinephrine produces dual effects of antagonizing neuromuscular relaxation through α-adrenergic effects and enhancing neuromuscular relaxation through β-adrenergic effects