Anti-Convulsant Drug Decreases Pain

Armen Hareyan's picture

The drug pregabalin administered before and after knee replacementsurgery, significantly decreased patient pain while increasing andexpediting mobility after surgery, according to a study by AsokumarBuvanendran, MD, director of Orthopedic Anesthesia and associateprofessor of Anesthesiology at Rush University Medical Center, Chicago.The study was presented at the American Society of Anesthesiologistsmeeting in San Francisco on October 14.

Total knee replacement (TKR) is one of the most prevalent and painfulorthopedic surgical procedures. With an increasing aging population,the number of knee replacements performed in the United Statesincreased by 69 percent from 1997 to 2005, with an estimated 314,000TKR procedures being done each year in the United States by 2010. Whileextremely successful in ultimately ending or minimizing knee pain anddisability, the procedure can cause postoperative knee stiffness,mechanical failure, and severe, chronic pain.

Buvanendran conducted the study with 60 TKR patients in two groups. Onegroup received 300 milligrams of pregabalin (an anti-convulsant) twohours before surgery and 150 milligrams twice a day for 14 daysfollowing surgery. The other patients were given placebos at the sameintervals. Both groups received pain medication through an epiduralcatheter during surgery and after surgery through a patient-controlleddevice.


The study found a "significant decrease" between the pregabalin andplacebo groups in pain medication consumption in the 32 hours followingsurgery. The pregabalin group also consistently reported pain levelsbetween two and four (on a scale of one to 10, with "10" being mostsevere) following surgery, and used less pain medication at all timepoints.

In addition, the patients' knee range of motion (ROM) following surgerywas higher in the pregabalin patients at hospital discharge: 84 degreescompared to 76 degrees among non-pregabalin patients. At 83 degrees apatient can climb stairs. Typically, it takes a patient a full week toreach that level, Buvanendran said.

Administration of pregabalin "decreased postoperative analgesicrequirements while improving function," Buvanendran said, noting thatthe ROM improvements are "especially important."

"When you can walk up and down stairs, it makes a huge difference inpatient life quality," he said. In addition, the improved range ofmotion allows patients to complete necessary post-surgicalrehabilitation more quickly.