Assessment of the bioavailability of an antibiotic prophylactic protocol in patients undergoing third molar surgery

The aim of this prospective study was to determine the antibiotic bioavailability of a prophylactic protocol in patients undergoing third molar surgery. Samples from 25 patients were analysed (average age 21 ± 3.89 years, range 18-33 years; 14 female). The patients received single-dose prophylaxis of 2 g amoxicillin orally 1 hour prior to third molar surgery. Venous blood (1.5 ml) and blood from the third molar socket (1.50 ml) were obtained. The amoxicillin plasma concentration was determined in both samples by high performance liquid chromatography with a diode-array detector (HPLC/DAD). Their associations with demographic variables (age, height, weight, body mass index (BMI), sex) and antibiotic exposure time were analyzed using linear regression models. The mean amoxicillin plasma level detected in the venous blood was 1.21 ± 1.17 μg/ml (range 0.49-6.34 μg/ml) and in the third molar socket was 4.14 ± 2.24 μg/ml (range 0.86-7.46 μg/ml) (P <  0.001). No relationship was observed between the bioavailability of the drug and the patient biometric indices evaluated. The prophylactic administration of 2 g amoxicillin in third molar surgery showed greater bioavailability in the molar socket than the concentrations established as necessary to inhibit the growth of microorganisms that cause oral infections. The results show the need to review the current infection control protocols in oral surgery in light of the overestimated doses observed.