Cyclobenzaprine

Cyclobenzaprine, brand names 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.

Medical use

After sustaining an injury, muscle spasms may occur to stabilize the affected body part and prevent further damage. They also generate pain. Cyclobenzaprine is FDA-approved 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.

Cyclobenzaprine has also shown effectiveness in the treatment of fibromyalgia symptoms, with a report of 4.8 patients needing treatment for each (1) patient reporting pain reduction (but no change in fatigue or tender points).