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Pregabalin not effective for chronic pain after traumatic nerve injury

However, same study found drug may be beneficial for lingering pain following surgery

Ingrid Torjesen

Tuesday, 25 September 2018

Pregabalin is not effective in controlling the chronic pain that sometimes develops following traumatic nerve injury, a study* published in the Journal of Neurology shows.

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 nerve injury syndromes that occur after motor vehicle accidents, falls, sports injuries, knee or hip replacement and surgeries such as hernia repair or mastectomy.

The risks factors and underlying mechanisms of this type of chronic pain are not well understood, but the types of symptoms patients describe like "burning", "unpleasant tingling," or "numbness" resemble other nerve pain syndromes like shingles pain. As a result, physicians trying to find useful non-opioid pain relievers have often turned to prescribing gabapentin or pregabalin.

A previous eight-week study had shown that pregabalin reduced pain intensity better than placebo in these chronic, post-traumatic pain syndromes. These results led many doctors to prescribe this medication for long-term pain.

This latest study – the longest such trial – included 539 individuals treated at 101 centres in North America, Europe, Africa, and Asia who were randomised to either prescribed pregabalin or a placebo and followed for three months.

The results showed that pregabalin was not effective in controlling pain for individuals with traumatic nerve injury. However, a retrospective analysis of a subgroup of study of participants, whose nerve pain was attributed to surgery, showed that the drug did provide better pain relief than placebo at three months.

"While these finding show that pregabalin is not effective in controlling the long-term pain for traumatic injury, it may provide relief for patients experience post-surgical pain," said John Markman, director of the Translational Pain Research Program in the University of Rochester Department of Neurosurgery and lead author of the study.

"The possibility that there was pain relief for those patients who had a hernia repair, or breast surgery for cancer, or a joint replacement lays the groundwork for future studies in these post-surgical syndromes where there is so much need for non-opioid treatments."

Chronic postsurgical pain syndromes occur in approximately one or two out of every 10 surgical patients and the levels are rated as intolerable after roughly one or two in every 100 operations.  Roughly one third of these patients are believed to have neuropathic pain or ongoing pain related to nerve injury and the rates vary widely by type of surgery.

One major challenge is that different biological changes in the nerves and other tissues that cause pain to persist after healing from trauma vary from one patient to the next. Currently, there is no diagnostic method that allows doctors to readily identify the patients whose pain will respond to a particular type of pain treatment.

"Given the rising rates of surgery and shrinking reliance on opioids, it is critical that we understand how to study new drugs that work differently in patients like the ones included in this study," Markman added.

* Markman J, Resnick M, Greenberg S, et al. Efficacy of pregabalin in post-traumatic peripheral neuropathic pain: a randomized, double-blind, placebo-controlled phase 3 trial. J Neurol, 2018. DOI: 10.1007/s00415-018-9063-9

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