Drugs help postop PRK discomfort

February 15, 2011

Patient comfort is a major concern after PRK.

Dr. Hofmeister and colleagues conducted a randomized prospective study in which they hypothesized that orally administered gabapentin would be as effective as oral oxycodone/acetaminophen for relieving discomfort after PRK without the sedating side effects associated with narcotics.

The use of gabapentin in this capacity is an off-label use, she explained.

The drug also is used for treating chronic pain and acute postoperative pain. The drug is given preoperatively and in combination with oral nonsteroidal drugs, such as ibuprofen, postoperatively to reduce the use of narcotics.

Ophthalmic use of the drug has not been reported in the literature, according to Dr. Hofmeister. The study included consecutive patients scheduled to undergo PRK to correct myopia with an ablation depth of 75 µm or less. Patients were divided into two groups; group A received 400 mg of oral gabapentin every 4 hours, and group B could use oxycodone/acetaminophen as needed for pain.

All procedures were performed using an excimer laser (VISX S4, Abbott Medical Optics). Mitomycin-C was not used for any cases. A bandage contact lens was placed in all patients at the end of surgery. Patients maintained a medication log postoperatively to record levels of pain, photophobia, tearing, and foreign body sensation on a visual analog scale. Patients also used preservative-free tetracaine, fluorometholone, gatifloxacin, oral ibuprofen, and artificial tears. Patients were examined postoperatively on days 1, 4, and 7.

A total of 163 patients (mean age, 28 years) were included in the study, 78 in the gabapentin group and 85 patients in the oxycodone/acetaminophen group. The myopia in both groups was moderate.

During the 7-day postoperative period, patients in the gabapentin group reported significantly (p = 0.009) worse pain levels, tearing (p = 0.025), foreign body sensation (p = 0.0001), and photophobia (p = 0.007) compared with the oxycodone/acetaminophen group, Dr. Hofmeister said.

Investigators also looked at the effect of tetracaine, but found that there was no difference in the use of the drug by the patients in both groups.

"For patients undergoing PRK for myopia, oxycodone/acetaminophen is more effective than gabapentin for reducing pain, tearing, photophobia, and foreign body sensation," Dr. Hofmeister concluded. "Tetracaine use was not a confounder in the results."

FYI

Cmdr. Elizabeth M. Hofmeister, MDE-mail: elizabeth.hofmeister@googlemail.com
; elizabeth.hofmeister@med.navy.milDr. Hofmeister has no financial interest in the subject matter. The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government.