Overdosage of colistimethate sodium can cause neuromuscular blockade characterized by paresthesia, lethargy, confusion, dizziness, ataxia, nystagmus, disorders of speech, and apnea. Respiratory muscle paralysis may lead to apnea, respiratory arrest, and death. Overdosage of the drug may also cause acute renal failure, manifested as decreased urine output and increases in serum concentrations of BUN and creatinine. If overdosage of colistimethate sodium occurs, the drug should be discontinued and general supportive measures initiated. Colistimethate sodium may be removed by hemodialysis and, to a lesser extent, by peritoneal dialysis.