SNOWMASS, COLO. – Sciatica and low back pain respond best to low doses of medications used in combination as opposed to high-dose monotherapy, David G. Borenstein, M.D., said at a symposium sponsored by the American College of Rheumatology.
There are no magic bullets. Instead, “it's trial and error and seeing what works with a patient,” said Dr. Borenstein, a textbook author and researcher who practices in a rheumatology group in Washington.
According to prescribing patterns, it appears that muscle relaxants are among the most effective medications for back pain, but they're more effective when used in combination with other medications.
In a telephone survey of patients with acute low back pain contacted 1 week after an office visit, the best outcomes appeared to be associated with a combination treatment using a muscle relaxant and an NSAID together. Other respondents were taking no medication, or opioids, acetaminophen, and muscle relaxants alone (Spine 1998;23:607–14).
Dr. Borenstein said the survey findings are consistent with his own clinical experience using combination regimens, which he said can minimize side effects and have a synergistic effect. He added that providers could use a lot more guidance on how to use drugs in combination; more dose-finding studies are needed.
In a report on two combined studies involving 1,405 patients with low back or neck pain, participants were randomly assigned to take the muscle relaxant cyclobenzaprine or placebo. Dr. Borenstein noted that the cyclobenzaprine outperformed placebo in three primary, patient-rated end points: relief from pain at the start of the day, assessment of medication helpfulness, and clinical global impression of change.
Interestingly, when the researchers looked at three doses–2.5 mg, 5 mg, and 10 mg–each taken three times daily, they found that all the doses were more effective than placebo. The 5-mg dose was no less effective than the 10-mg dose and was less likely to cause sedation, Dr. Borenstein said (Clin. Ther. 2003;25:1056–73).
Future strategies for treating low back pain may involve biologics such as infliximab, Dr. Borenstein said.
Yet to be published open-label trials of infliximab, conducted in Finland, have shown significant efficacy within hours of patients' receiving a single injection, compared with controls that were given sham injections of saline.
Yet the only double-blinded, controlled trial reported to date found no benefit relative to placebo. The lack of efficacy seen in this unpublished trial may have been due to the high placebo response, Dr. Borenstein said. Another trial is underway.