Peroral antibiotic prophylaxis in upper gastrointestinal surgery. A study of biological availability

Abstract Sixteen patients undergoing elective upper gastrointestinal surgery with presumed normal gastrointestinal function received peroral trimethoprim-sulfamethoxazole (TMP/SMZ 160/800 mg) and metronidazole (2 g) in the morning regardless of what time the operation was to be started. The concentration of SMZ in plasma was measured before and after the operation. Only 37 per cent of the patients were found to have adequate levels of SMZ concentration. Patients with grave obesity or malignant disease of the liver, biliary tract or pancreas had concentrations below the minimal inhibitory concentrations for species of Enterobacteriacae. Peroral antibiotic prophylaxis is therefore not suitable in all types of upper gastrointestinal surgery.