Neuromuscular blocking property of amikacin in man

The effect of amikacin on the neuromuscular junction was studied in man during anesthesia and surgery. Amikacin alone did not show any neuromuscular blocking action in normal man in therapeutic doses (100-200 mg). However, during recovery from either d-tubocurarine block or phase II block with succinylcholine, the intravenous administration of 200 mg of amikacin caused a decrease in twitch tension. This neuromuscular block aggravated by amikacin was antagonized by edrophonium (10 mg) or calcium chloride (400 mg). Data obtained from the peroneal nerve-anterior tibial muscle preparation of rabbits suggested that the neuromuscular blocking potency of amikacin was one-twelfth of that of kanamycin in therapeutic doses. Although amikacin is thus less potent than kanamycin, caution should be taken in its use for patients with myasthenic state.