Dicloxacillin concentrations in amputation.

We treated 18 patients undergoing major lower limb amputation due to ischemia by intravenous administration of 1 g dicloxacillin either 0, 3, or 6 hours before surgery followed by a similar dose 8 hours after the first dose. The administration immediately before the operation resulted in the highest peroperative antibiotic concentrations in the muscular and subcutaneous tissue at the amputation level, exceeding the MIC value of Staphylococcus aureus. Similarly, the concentrations in drain fluid were highest in these patients. The median drain secretion later than 12 hours after surgery amounted to only 5 mL, and at that time the concentration of dicloxacillin was less than the MIC of Staphylococcus aureus in all the samples.