Investigation of the Optimal Interval of Perioperative Serum Flomoxef Administration in Hepatobiliary-Pancreatic Surgery.

Background: Perioperative prophylactic antimicrobials are re-administered at intervals of twice their half-life. However, the actual concentrations of antimicrobial agents and the degree of elevation remain unelucidated.

Methods: This prospective cohort study was conducted at a single tertiary care center. Serum concentrations were evaluated in patients who underwent hepatobiliary-pancreatic surgery between April 2019 and December 2020 and received an additional dose of flomoxef (FMOX) every 3 h or 5 h during the surgical procedure based on their renal function.

Results: Among the 31 participants, 25 and six received FMOX every 3 h and 5 h, respectively. Analysis based on renal function revealed median FMOX concentrations of 9.88 mg/L and 9.85 mg/L (p = 0.09) for patients with creatinine clearance (Ccr) >60 mL/min and 14.26 mg/L and 20.03 mg/L (p = 0.02) for the patients with Ccr ≤60 mL/min at 3 h and 6 h, respectively, with notable elevation at Ccr ≤60 mL/min. Moreover, the serum FMOX concentration at 6 h for the 3-h dosing patients with Ccr ≤60 mL/min was significantly higher than the concentration at 5 h for the 5-h dosing patients with Ccr ≤60 mL/min (20.03 mg/L vs. 12.85 mg/L, p = 0.04). Although serum concentrations at 3-h and 6-h intervals did not differ significantly in patients with Ccr ≥60 mL/min, these significantly increased in patients with Ccr <60 mL/min.

Conclusions: Administering FMOX every 3 h when Ccr is ≥60 mL/min and every 5 h when Ccr is <60 mL/min are appropriate.