Background The administration of
antibiotic prophylaxis during cardiothoracic surgery can reduce the rate of
surgical site infections. Trials of cardiothoracic
antibiotic prophylaxis have found it to be beneficial in preventing
postoperative wound infections. Objective To determine the more appropriate timing of repeated doses of
ampicillin-sulbactam to maintain adequate
antibiotic concentrations during cardiovascular surgery in anuric patients. Method Five adult anuric dialysis patients who received
ampicillin-sulbactam during cardiovascular surgery at Kagoshima University Hospital, the total plasma concentrations of
ampicillin and
sulbactam were monitored after
ampicillin (1 g)-sulbactam (0.5 g) administration. Pharmacokinetic parameters were estimated and used to predict the free plasma concentrations of
ampicillin and
sulbactam. Results The mean values for the volume of distribution, total clearance, elimination rate constant and the elimination half-life for
ampicillin were 8.9 ± 2.4 L, 1.69 ± 0.93 L/h, 0.180 ± 0.059 h(-1) and 4.23 ± 1.48 h, respectively. The pharmacokinetic parameters were similar to those of
sulbactam. When
ampicillin (1 g)-sulbactam (0.5 g) was intravenously administered at 8, 12 and 24 h intervals, the predicted free trough plasma concentrations of
ampicillin were 28.72, 12.06 and 1.25 μg/mL, respectively. Conclusion We suggest that
ampicillin (1 g)-sulbactam (0.5 g) should be intravenously administered every 12 h in order to maintain a free
ampicillin concentration of more than 12 μg/mL in anuric patients during cardiovascular surgery.