Surgical antibiotic prophylaxis for obese patients

Antibiotic pharmacokinetics are altered in obese patients, so dosage adjustments may be necessary. Weight-based antimicrobial dosing has not been shown to reduce the incidence of postoperative infection in obese patients. However, data from small pharmacokinetic studies suggest 2 g doses of cefazolin may result in inadequate tissue levels in obese patients. Given the safety and low cost of cefazolin, it is reasonable to increase the cefazolin dose to 3 g in patients who weigh more than 120 kg and have normal kidney function.