<P> Cyclobenzaprine, sold under the brand name Flexeril among others, is a muscle relaxer medication used to relieve skeletal muscle spasms and associated pain in acute musculoskeletal conditions . It is the best - studied drug for this application . It has also been used off - label for fibromyalgia treatment . </P> <P> As of 2015 the cost for a typical course of medication in the United States is less than US $25 . </P> <P> After sustaining an injury, painful muscle spasms may occur to stabilize the affected body part and prevent further damage . Cyclobenzaprine is used to treat such muscle spasms associated with acute, painful musculoskeletal conditions . It decreases pain in the first two weeks, peaking in the first few days, but has no proven benefit after two weeks . Since no benefit is proven beyond that, therapy should not be continued long - term . It is not useful for spasticity due to neurologic conditions such as cerebral palsy . </P> <P> Cyclobenzaprine has also shown effectiveness in the treatment of fibromyalgia symptoms, with a reported number needed to treat of 4.8 (meaning that 1 patient out of every 4.8 benefits from treatment) for pain reduction, but no change in fatigue or tender points . It may also be used along with other treatments for tetanus . </P>

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