Opioids Help Reduce Pain from Nerve Damage

A study has found that a morphine-like medication can significantly improve pain in patients suffering from chronic pain due to nervous system damage. The study was published in the March 23, 2003, issue of The New England Journal of Medicine.

Some doctors are reluctant to prescribe opioids for patients with neuropathic pain because of concerns about ineffectiveness, addiction, and side effects. Animal studies have shown them to be relatively ineffective. In contrast, the new study found that the ability of an opioid called levorphanol to reduce neuropathic pain was similar to that of tricyclic antidepressants and the anticonvulsant gabapentin, two drugs commonly used for neuropathic pain. The study also showed that high-dose treatment provided greater pain reduction than a lower-dose regimen, and patients did not become tolerant of the drug.

However, researchers noted that more patients in the high-dose group dropped out of the study, complaining of a range of side effects, including restlessness, depression, and behavior changes. The study involved 81 patients, 59 of whom completed the eight-week therapy with levorphanol. All had severe and long-lasting pain.

"The study shows that opioids can be beneficial for relief of neuropathic pain but don't help everyone,” said lead author Michael Rowbotham, M.D., professor of clinical neurology and anesthesia at the University of California, San Francisco (UCSF, USA; www.ucsf.edu). "The benefits must be weighed against the drawbacks for each patient. Some may take a dose high enough to produce many side effects but still experience no relief of their pain.”




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