Commonly prescribed painkiller not effective in controlling lower back pain

"Chronic low back pain is one of the most common reasons why older adults go to the doctor and lumbar stenosis is the leading indication for surgery in this age group," said John Markman, M.D., director of the Translational Pain Research Program in the University of Rochester Department of Neurosurgery and lead author of the study. "While physicians have increasingly looked for medication alternatives to opioid pain medication like gabapentin and pregabalin to help these patients manage their pain, until now there has been no credible evidence as to whether or not these treatments are effective for this problem."

Pregabalin, which is marketed by Pfizer under the name Lyrica, is approved to treat chronic pain associated with shingles, spinal cord injury, fibromyalgia, and diabetic peripheral neuropathy. However, it is also commonly prescribed as an "off label" treatment for chronic low back pain syndromes like lumbar spinal stenosis.

Lumbar spinal stenosis is brought about by a narrowing of the spinal canal caused by the degeneration of the vertebrae, discs, muscles, and ligaments that comprise the spinal column. This results in a compression of nerve roots that can trigger pain, tingling, and numbness in the lower back, buttocks, and legs. The pain is most commonly experienced when a person is upright or walking and can be lessened by bending forward at the waist, which is often why one sees older adults hunched over with a cane or a walker.

While some narrowing of the spinal canal occurs with normal aging and does not always cause pain, more severe compression of nerves limits mobility and leads patients to try stronger pain medications and epidural steroid injections in an attempt to control the pain that is associated with walking and standing.

Patients also often decide to undergo surgery that removes a portion of the bone or disc to give the nerve roots more room. The procedure -- called a lumbar laminectomy -- is the most common reason for spine surgery in people over the age of 60. While the surgery is initially highly successful, the pain often returns after a number of years. Also, for some patients, surgery is not an option.

For a long time, physicians have attempted to expand the arsenal of medications available to treat this condition. In fact, it is estimated that more than two thirds of the pain treatment regimens currently being used for lumbar spinal stenosis consist of drugs like pregabalin that are not approved by the Food and Drug Administration for the condition.

The new study employed a novel approach to evaluating the effectiveness of pain treatments. Because the pain associated with the lumbar spinal stenosis is present when a person is upright or walking, the researchers asked individuals with the condition to report their pain levels while walking on a treadmill. They found there was no significant difference in the levels of pain experienced by those taking the drug and those that received a placebo.

"Given the cost and potential side effects associated with pregabalin, it is critical that we understand the efficacy of this drug," Markman said. "This study convincingly demonstrates a lack of relief with pregabalin for the walking pain associated with lumbar spinal stenosis."