Some effects of the aminoglycoside antibiotic amikacin on neuromuscular and autonomic transmission.

The effects of the new aminoglycoside antibiotic amikacin on neurohumoral transmission were tested in the anaesthetized cat, and in mouse, rat and chick isolated nerve-muscle preparations. Amikacin had blocking actions on both autonomic and neuromuscular transmission. The autonomic effects were caused mainly by ganglion blockade and were reversed by calcium. The amikacin-induced neuromuscular blockade reculted from a decreased release of acetylcholine and a reduced postjunctional sensitivity. Intracellular recording from end-plates in the rat diaphragm demonstrated that amikacin had magnesium-like effects on acetylcholine release. The blockade was reversed completely by calcium, 4-aminopyridine and 3,4-diaminopyridine and partially by neostigmine. The neuromuscular effects of amikacin in vivo were augmented greatly after pretreatment with tubocurarine. It is concluded that care should be exercised if amikacin is administered during surgery in conjunction with tubocurarine.