A single 75-mg dose of sodium colistimethate was administered intramuscularly to 39 subjects with varying degrees of renal function; 17 of the subjects were undergoing dialysis therapy. Sequential concentrations of the drug in blood and dialysate were determined. When the endogenous creatinine clearance was below 20 ml/min, sodium colistimethate blood levels and their duration of elevation were inversely proportional to degree of renal impairment.
Approximately 1 mg of sodium colistimethate was removed from the blood per hour during peritoneal dialysis, and the drug was cleared 30% as effectively as urea. Detectable quantities of sodium colistimethate were not removed from the blood by Kiil or Kolff hemodialysis. The treatment for serious toxicity or overdosage with sodium colistimethate is peritoneal dialysis.
Recommended dosages of sodium colistimethate in patients with renal insufficiency are:  when endogenous creatinine clearance exceeds 20 ml/min, 75 to 100% of the recommended daily dose divided into doses every 12 hr;  when endogenous creatinine clearance is between 5 and 20 ml/min, 50% of the usual daily dose divided into doses every 12 hr; and  when endogenous creatinine clearance is less than 5 ml/min, 30 to 35% of the normally recommended dose divided into doses every 12 to 18 hr.