Study finds bupropion SR effective in treating neuropathic pain
ST. PAUL, MN -- Patients with neuropathic pain found greater relief, and fewer side effects, when treated with bupropion SR (sustained-release) than with commonly prescribed treatments. These findings came from a study conducted at the University of Arizona Neurology Clinic and Pain Clinic in Tucson, and published in the November 13 issue of Neurology.
"The results of our placebo-controlled study support previous preliminary data that bupropion SR, at a dosage of 150 to 300 mg/day, may be clinically effective for the treatment of neuropathic pain," according to study author Marilyn Semenchuk, PharmD, Dept. of Neurology at the University of Arizona at Tucson. Approximately three-quarters of the patients treated in the trial reported that their pain was improved by an average of 30 percent with bupropion SR.
Neuropathic pain, which results from a disturbance of the peripheral or central nervous system, includes symptoms such as shooting and burning sensations, numbness, and tingling. Neuropathic pain has commonly been treated with tricyclic antidepressants (TCAs). But many patients stop taking these drugs because they may not effectively reduce the pain, or because the drugs leave them with intolerable side effects. Bupropion SR is a second generation non-TCA.
The forty-one patients who participated in the study were all clinically diagnosed with neuropathic pain, were screened to determine the absence of depression, and were medically stable. Semenchuk said the researchers limited the study to nondepressed patients since there is a belief that patients with chronic pain may also be depressed and the reason the antidepressant medications work for treating neuropathic pain is not as an analgesic but by alleviating the depression. The argument has been that once the depression is alleviated, the pain is better. "By using nondepressed patients, the previous argument doesn't hold," said Semenchuk .
The 12-week outpatient study compared bupropion SR 150 mg with an inactive placebo. Neither the patient nor the doctor knew whether the patient was taking the bupropion or the placebo. Half the patients were on the placebo for the first six weeks, and the medication for the second six weeks. The other half received the medication first.
Seventy-three percent, or 30 of the patients reported their pain was improved or much improved after six weeks of bupropion therapy, whereas 90 percent claimed their pain became worse or remained unchanged while receiving the placebo. Semenchuk recommended additional larger scale studies to confirm the results.
The study was supported, in part, by a grant from Glaxowellcome, a division of GlaxoSmithKline.
The American Academy of Neurology, an association of more than 17,700 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. For more information about the American Academy of Neurology, visit its web site at www.aan.com.