A drug commonly prescribed to treat lower back pain caused by lumbar spinal stenosis is no more effective than a placebo, according to a small new study by researchers at the University of Rochester.
Pregabalin, an anti-epileptic drug marketed by Pfizer (NYSE: PFE) under the brand name Lyrica, is approved by the Food and Drug Administration to treat chronic pain associated with shingles, fibromyalgia, diabetic peripheral neuropathy, and spinal cord injury. Lyrica is also prescribed “off label” to treat other chronic pain syndromes such as lumbar spinal stenosis, the most common type of lower back pain in older adults.
It is estimated that more than two-thirds of the pain medications currently being used for lumbar spinal stenosis consist of drugs like pregabalin that are not approved by the FDA for the condition.
“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, MD, director of the Translational Pain Research Program in the University of Rochester’s Department of Neurosurgery and lead author of the study being published in the journal Neurology.
“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.”
Lumbar spinal stenosis is caused by a narrowing of the spinal canal caused by the degeneration of the vertebrae, discs, muscles, and ligaments in the spinal column. This causes 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.
In the double-blind study, 29 subjects over the age of 50 with lumbar spinal stenosis were randomly selected to receive pregabalin for 10 days followed by placebo; or they started with a placebo and were switched to pregabalin. Participants were asked to walk on a treadmill for 15 minutes and report their pain levels.
Researchers found no significant difference in the levels of pain experienced by those taking the pregabalin and those that received the placebo. Over 40 percent of the study participants complained of dizziness while taking pregabalin, a common side effect of the drug.
“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.”
“Despite the prevalent use of oral pain medications for the treatment of patients diagnosed with lumbar spinal stenosis, very few high-quality studies have investigated their efficacy. Furthermore, only one published unblinded randomized controlled trial supports the use of an antiepileptic drug, gabapentin, when combined with standard treatment (i.e., a combination of exercise, nonsteroidal anti-inflammatory drugs, and bracing) for neurogenic claudication associated with lumbar spinal stenosis.”
Pfizer funded the University of Rochester study. Pregabalin (Lyrica) is one of the drugmaker’s biggest moneymakers, generating sales of over $2.3 billion in the past year.
Although approved by the FDA to treat pain caused by fibromyalgia, a survey of over 1,300 fibromyalgia patients by National Pain Report found that only 10% thought it was very effective in treating their symptoms. Twenty-nine percent said Lyrica “helps a little” and 61% said it did not help at all.