Abstract
Purpose: :
To compare the efficacy of oral gabapentin vs. placebo for the control of pain following photorefractive keratectomy (PRK).
Methods: :
This study is a prospective randomized double-masked placebo-controlled trial of 40 patients who underwent PRK for correction of myopia or myopic astigmatism. Corneal epithelial removal was performed via Amoils epithelial scrubber (Innovative Excimer Solutions, Inc.) and ablation was performed using the Wavelight ALLEGRETO WAVE Eye-Q 400 MHz LASER platform (Wavelight AG,Erlangen,Germany). Standard medications were used following PRK. Patients were randomized to receive gabapentin 300mg (GABA) or placebo (PLA) TID, beginning 2 days prior to surgery and continued for 4 days after surgery, for a total of 7 days. Primary outcome measures were pain levels reported at 2 hrs post-op, and on post-op days (POD) 1-4; and maximum pain levels daily over a 24 hr. period, using the visual analog pain scale (VAS). Statistical analyses were performed using SPSS v.15.0. A repeated measures analysis of variance compared the GABA versus PLA groups over time for current and maximum pain scores. T-tests analyzed pain scores at each time interval (p<0.05 statistically significant). Secondary outcome measures were frequency of use of an oral narcotic pain-reliever, Percocet® [oxycodone 5mg/ acetaminophen 325 mg;Endo pharmaceuticals,Chadds Ford,PA,USA], assessed by performing a pill count of remaining Percocet® tablets on the POD 4 visit. A Mann-Whitney test compared the two groups’ Percocet® use (p<0.05 statistically significant).
Results: :
20 patients were enrolled in each treatment group (see Figure 1.) Among the two treatment groups, there were no statistically significant differences in current or maximum reported pain at any time point or decrease in frequency of use of Percocet® for breakthrough pain following PRK.
Conclusions: :
In this small cohort, when compared to placebo, gabapentin showed no improvement in pain measures or in decreasing the frequency of use of oral narcotics for breakthrough pain following PRK at the intervals tested.
Clinical Trial: :
www.clinicaltrials.gov NCT00793910
Keywords: refractive surgery: PRK