Cyclobenzaprine and back pain - A meta-analysis

Background: Back pain is a common problem for which cyclobenzaprine hydroch loride is frequently prescribed. Objective: To perform a systematic review of cyclobenzaprine's effectivenes s in the treatment of back pain. Methods: We searched MEDLINE, PsycLIT, CINAHL, EMBASE, AIDSLINE, HEALTHSTAR , CANCERLIT, the Cochrane Library, Micromedex, Federal Research in Progress , and the references of reviewed articles, and contacted Merck, Sharpe and Dohme for English-language, randomized, placebo-controlled trials of cyclob enzaprine in adults with back pain. Outcomes included global improvement an d 5 specific domains of back pain (local pain, muscle spasm, range of motio n, tenderness to palpation, and activities of daily living). Study quality was assessed using the methods of Jadad. Summary outcomes were obtained usi ng a random-effects model. Results: Patients treated with cyclobenzaprine were nearly 5 times (odds ra tio, 4.7; 95% confidence interval, 2.7-8.1) as likely to report symptom imp rovement by day 14 as were those treated with placebo. Slightly fewer than 3 individuals (2.7; 95% confidence interval, 2.0-4.2) needed treatment for 1 to improve. The magnitude of this improvement was modest, with an effect size of 0.38 to 0.58 in all 5 outcomes (local pain, muscle spasm, tendernes s to palpation, range of motion, and activities of daily living). Treatment efficacy for these 5 outcomes was greatest early, in the first few days of treatment, declining after the first week. Patients receiving cyclobenzapr ine also experienced more adverse effects, the most common being drowsiness . Conclusions: Cyclobenzaprine is more effective than placebo in the manageme nt of back pain; the effect is modest and comes at the price of greater adv erse effects. The effect is greatest in the first 4 days of treatment, sugg esting that shorter courses may be better. Studies comparing the relative v alue of acetaminophen, nonsteroidal anti-inflammatory drugs, and cyclobenza prine individually and in combination in the treatment of back pain are nee ded.