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.^[3] It decreases pain in the first two weeks,^[4][12] peaking in the first few days, but has no proven benefit after two weeks.^[4][13] Since no benefit is proven beyond that, therapy should not be continued long-term.^[14] It is not useful for spasticity due to neurologic conditions such as cerebral palsy.^[14][15]

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).^[16] Like other tricyclic antidepressants, it is also prescribed off-label as a sleep-aid.[