Does preemptive gabapentin modulate cytokine response in total knee arthroplasty? A placebo controlled study

BACKGROUND: Gabapentin, as a structural analogue of γ-aminobutyric acid, has been investigated to provide pain relief in the early postoperative period following various surgical interventions. OBJECTIVES: The objective of this study was to investigate whether preemptive oral administration of gabapentin 800 mg can reduce postoperative pain and modulate the inflammatory cytokine response in comparison to placebo in patients undergoing total knee arthroplasty under general anesthesia. MATERIAL AND METHODS: Fifty-two patients were randomly divided into 2 groups before surgery, either to receive peroral gabapentin 800 mg or placebo drug, 1 h before surgery. All patients had general anesthesia with endotracheal intubation, in a standardized fashion, by the same anesthetist. Thirty min before completion of surgery, intramuscular diclofenac sodium 75 mg was administered. Following extubation, visual analogue pain scale (VAS) scores and additional analgesic requirements were recorded at 15 min at post-anesthesia care unit (PACU), and at 4th and 24th h postoperatively. Plasma levels of interleukin 6 (IL-6), and tumor necrosis factor R (TNF-R) were measured at predetermined time points (T0 1 h before administration of gabapentin, T1 at postoperative the 4th h mark, and T2 at postoperative at the 24th h mark). RESULTS: The VAS scores at postoperative 4th h were significantly higher in placebo and gabapentin groups compared with VAS scores at PACU and at 24th h. The groups did not differ in terms of additional analgesic requirements. In gabapentin group, IL-6 levels at T1 and T2 were significantly lower in comparison to values measured in placebo group at the same time points. This difference was not significant in TNF-R levels between the groups. CONCLUSIONS: Though preemptive oral gabapentin administration did not reduce postoperative pain and analgesic requirements in total knee arthroplasty surgery, it attenuated IL-6 production on the first postoperative day.