For Acute, Painful Musculoskeletal Conditions, Cyclobenzaprine Enables More Rapid Return to Function than Placebo

BALTIMORE, Md.—Patients with acute, painful musculoskeletal conditions can be returned to normal activities rapidly if the spasm-pain-spasm cycle is interrupted promptly. Therefore, time to response following medication administration is a clinically meaningful assessment in this patient population, investigators reported during the American Pain Society's 29th Annual Scientific Meeting.

To determine time to response, Stephen Landy, MD, of the University of Tennessee Medical School, Memphis, Tenn., and colleagues randomized 504 patients with muscle spasm of cervical/lumbar origin to one of four groups: cyclobenzaprine extended-release (CER) 15 mg once daily (n=127); CER 30 mg once daily (n=126); cyclobenzaprine immediate-release (CIR) 10 mg tid (n=123), or placebo (n=128). The investigators analyzed three variables: patient's rating of medication helpfulness; relief from local pain; and relief from restriction of movement.

Recovery, defined as time to a lot/complete relief of local pain or restriction of movement, occurred more rapidly in patients taking CER and CIR compared with placebo. Time to achieve a lot/complete relief from restriction of movement was 6 days with CER 15 mg, 5 days with CER 30 mg, 5 days with CIR 10 mg, and 7 days with placebo. Time to achieve a very good/excellent rating was a median 10 days with CER 15 mg, 8 days with CER 30 mg, 7 days with CIR 10 mg, and more than 14 days with placebo. For relief from local pain, time to achieve a lot/complete relief was 6 days with CER 15 mg, 5 days with CER 30 mg, 5 days with CIR 10 mg, and 8 days with placebo. Adverse events were generally mild. Somnolence was the most common adverse event leading to discontinuation from the study. Patients reported less somnolence with CER than CIR.

Those in both the CER and the CIR treatment groups had a more rapid response compared with the placebo group. The investigators concluded that given that muscle spasms may affect ability to work, accelerated response may have economic—as well as medical—benefits, allowing patients to resume normal activities sooner.