Oral gabapentin for photorefractive keratectomy pain

PURPOSE: To compare the efficacy of oral gabapentin versus placebo for the control of severe pain after photorefractive keratectomy (PRK). SETTING: Center for Refractive Surgery, Walter Reed Army Medical Center, Washington, DC, USA. DESIGN: Randomized masked clinical trial. METHODS: This single-center clinical trial comprised active-duty United States Army soldiers aged 21 years or older having bilateral PRK for myopia with or without astigmatism. Patients received gabapentin 300 mg or placebo 3 times daily for 7 days beginning 2 days before and continuing for 4 days after surgery. Current and maximum pain levels were assessed using the Visual Analog Pain scale 2 hours after surgery and then daily on days 1 through 4. Repeated-measures analysis of variance (ANOVA) was used to compare the current and maximum pain scores over time between the gabapentin group and the placebo group. The Fisher exact test was used to determine whether there was a difference in severe pain (>7/10) between the 2 groups. RESULTS: Forty-two patients received gabapentin and 41 patients, placebo. The repeated-measures ANOVA showed no significant difference between the 2 groups in current pain (P=.84) or in maximum pain over time (P=.35). Oxycodone acetaminophen use in the gabapentin group was significantly higher than in the placebo group 1 day postoperatively (P=.034). CONCLUSION: When added to a standardized postoperative pain regimen, gabapentin use led to no additional improvement in PRK pain control compared with a placebo at the dose and the time intervals tested.