Potentiation of magnesium-induced neuromuscular weakness by gentamicin.

A term neonate with hypermagnesemia secondary to maternal administration of MgSO4 for pre-eclampsia had a respiratory arrest after receiving gentamicin im. The neuromuscular tracings and sequential physician exams done before and after administering gentamicin suggest aminoglycosides may potentiate a magnesium-induced impairment of neuromuscular transmission and cause muscular weakness in neonates.