Cyclobenzaprine drug treatment for myofascial pain (a painful condition of the facial muscles) in adults

Myofascial pain (MP) is a painful condition of the muscles characterized by pain transmitted from trigger points (TP) within connective tissue surrounding and separating muscles (myofascial structures). TP can be located where the pain is felt, or can be at a distance from it. Cyclobenzaprine, one of the drugs used to treat MP, is taken as a pill. It is a muscle relaxant, particularly used to improve quality of sleep and to reduce pain. It suppresses muscle spasms - and so may prevent pain caused by MP - without interfering with muscle function. The purpose of this review was to assess how effective cyclobenzaprine is at reducing pain and improving sleep in patients with MP. We searched extensively through scientific publications and found two trials, with a total of 79 participants. These tested cyclobenzaprine against another drug called clonazepam, and fake medication (placebo), or against injections of a local anesthetic called lidocaine. A total of 35 of the 79 participants in the two trials were given cyclobenzaprine. Cyclobenzaprine was slightly better than clonazepam and placebo at reducing jaw pain, but was no better at improving sleep quality. The results from the other trial were not scientifically reliable because of the small number of participants involved, but lidocaine injections seemed to reduce pain slightly better than cyclobenzaprine pills. Despite this result, it is likely that, because it is uncomfortable to receive any form of injection, people who suffer from MP will prefer to be treated with cyclobenzaprine pills. There were no life-threatening adverse events associated with any of the medications studied. Further studies are needed to show whether cyclobenzaprine really works for treating MP, but at the moment doctors cannot say whether it is really useful.