Pilot Study Underway at UAB

A key area in acute pain research focuses on new analgesics or combinations to reduce the need for opioids and their unwelcome side effects.

UAB investigators have joined the search with a new study of the gabapentinoid pregabalin (Lyrica), a nonnarcotic that is Food and Drug Administration-approved for diabetic peripheral neuropathy, postherpetic neuralgia, partial onset seizures in epilepsy, and since June 2007, for fibromyalgia.

“A growing body of evidence suggests that gabapentin, as a peri- or postoperative adjunct, significantly lowers pain scores and reduces opioid use in certain postsurgical patients,” says UAB orthopaedic surgeon David A. Volgas, MD (BMC Anesthesiol. 2007;7[1]:6; Spine. 2007;32[9]:939-942; Anesth Analg. 2004;98[5]:1370-1373). “Gabapentin’s exact mechanism of action is unclear, but it appears to attenuate the hyperexcitability of the dorsal horn neurons, reducing pain sensation,” he says. “Pregabalin works through the same pathways, and preliminary studies indicate equivalent efficacy with fewer dose-related adverse effects,” says study coinvestigator and anesthesiologist Aimee H. Walsh, MD, who is medical director of UAB’s Pain Treatment Clinic.

Volgas and Walsh are evaluating pregabalin’s effectiveness in postoperative pain management for patients who have sustained an orthopaedic fracture, including pelvic fractures, that requires operative fixation. Only patients who undergo a single surgical episode will meet the inclusion criteria.

The need for opioids varies by patient, but the drugs often are required for weeks after surgical repair, either due to incision pain, rehabilitation, or fracture-related nerve injury. “Opioids do not alleviate true neurogenic pain associated with fractures,” Volgas says.

Pregabalin, as part of a multimodal approach to managing acute postoperative pain, may lessen such nerve pain and reduce opioid usage, thereby avoiding side effects (sedation, respiratory depression, concentration problems) and potential for addiction.

Volgas and Walsh plan to enroll 100 patients aged 19 to 70 years for the pilot study that started in May. Prior to surgery investigators randomize patients to placebo or pregabalin, and participants receive narcotic pain medication as determined by the attending physician. On postoperative day one, patients are given oral oxycodone as needed with Demerol for breakthrough pain. In addition, they receive pregabalin (either 75 mg or 150 mg twice a day) or placebo. On discharge, participants are given hydrocodone and pregabalin or placebo. Investigators will follow patients for 3 months.

The primary end points are the amount of narcotic used during hospitalization and the outpatient period. Other end points include pain scores, the time and frequency of use of rescue analgesics, quality of life parameters, and adverse events.

“We anticipate better pain control with fewer opioid-related adverse effects in the groups receiving pregabalin. This drug could be an effective adjunct to pain management in patients, such as elderly individuals, who are at risk for becoming overnarcotized,” Volgas says.

For more information:
Dr. David Volgas
Dr. Aimee Walsh
1.800.UAB.MIST
mist@uabmc.edu