Walter Allan Steigleman, MD
University of Florida
Co-Authors: Yujia Zhou1, Kayla Swiatek1
1University of Florida
Background: PRK is a commonly performed corneal refractive surgery for the correction of refractive error. Keratorefractive surgeons prescribe topical and oral medications to promote healing and reduce post-operative discomfort after PRK, with additional topical anesthetics and/or oral narcotics for break-through pain. Current evidence, however, demonstrates that opioid use is associated with unfavorable side effects, and legitimate opioid prescriptions have fueled the current opioid addiction crisis. A safe, yet effective alternative to opioid medication in the management of post-operative PRK pain should be investigated.
Objective: To compare the safety and efficacy of a low-tetrahydrocannabidiol-containing oral cannabidiol (CBD) chemovar with oral codeine-acetaminophen (T3) for controlling post-operative PRK pain.
Methods: In this crossover, randomized, paired-eye controlled trial, 35 participants were randomized to receive either a CBD chemovar or T3 to manage post-operative PRK pain for their first eye and the other treatment for their second eye. Adult myopic participants meeting criteria for PRK without surgical or medical contraindications were included. Primary outcome measures were self-reported side effects, including pain, nausea, vomiting, diarrhea, constipation, or altered sensorium, after PRK. Altered sensorium included drowsiness, clouded thinking, or change in sensory experience. Participants reported their side effects on an integer scale from 0-10 with the maximum and total score over a 5-day post-operative period recorded for each side effect. Secondary outcome measures were visual acuity and responses to surveys examining satisfaction, quality of life, and ocular surface symptoms pre- and post-operatively at various time points. Non-parametric U-test was used to determine differences in survey responses.
Results: Of the 35 participants, 16 were randomized to Group 1 (assigned to take CBD first) and 19 were randomized to Group 2 (assigned to take T3 first). For both groups, there was no significant difference in maximum or total self-reported pain post-operatively between drugs. There was also no significant difference in maximum self-reported side effects between drugs. There was a statistically significant increase in total sensorium reported in those taking CBD compared to T3 (p< 0.039). More specifically, Group 1 participants assigned to take CBD first reported higher sensorium than those who took T3, while Group 2 participants assigned to take CBD second did not report higher sensorium. Both groups yielded no significant difference in post-operative visual acuity or quality of vision between drugs.
Conclusions: This crossover, randomized, paired-eye controlled trial established no significant difference in the efficacy of T3 and a CBD chemovar for the control of post-PRK pain.