PHARMACOKINETICS OF AMPICILLIN-SULBACTAM IN PATIENTS UNDERGOING COLORECTAL SURGERY - MEASUREMENTS IN SERUM, THE COLONIC WALL AND IN TISSUE AT THE INCISION SITE

The concentrations of ampicillin and sulbactam were determined in seru m, colonic wall and incision site tissues from 23 patients undergoing elective colorectal surgery after infusion of a high-dose regimen (2 g ampicillin/1 g sulbactam) or a low-dose regimen (1 g ampicillin/0.5 g sulbactam). The results confirmed that ampicillin and sulbactam penet rated well into the tissues studied and reached therapeutically effect ive concentrations at the various sites. The high dose regimen showed higher concentrations of both compounds in serum and tissues, indicati ng a longer period of perioperative protection against bacterial patho gens. Thus, about 39 min after the end of the infusion of the high-dos e regimen, the mean concentration of ampicillin was 68.8 +/- 31.2 mu g /g and of sulbactam 23.4 +/- 6.3 mu g/g in the tissue of the colonic w all. Low-dose prophylaxis, showing mean tissue concentrations of ampic illin of 35.6 +/- 7.0 mu g/g and of sulbactam of 14.2 +/- 2.4 mu g/g a bout 48 min after the infusion, is appropriate if the duration of surg ery does not significantly exceed 2 h.