Search

Study objective: We evaluate the analgesic and side effects of adding cyclobenzaprine to ibuprofen in emergency department patients with acute myofascial strain. Methods: A randomized, prospective, double-blind study was conducted at an urban teaching ED with an annual census of 44,000. One hundred two patients aged 18 to 70 years with acute myofascial strain caused by minor trauma within the prior 48 hours were included, and 77 patients completed the protocol. Each patient received a single dose of 800 mg of ibuprofen in the ED and a vial of 6 capsules containing 800 mg of ibuprofen to take every 8 hours as needed after discharge from the ED. In addition, 51 patients received a single dose of 10 mg of cyclobenzaprine and a vial of 6 capsules containing 10 mg of cyclobenzaprine to take every 8 hours as needed after discharge from the ED; the remaining 51 patients received an identically labeled placebo capsule and vial of placebo capsules to take every 8 hours as needed after discharge from the ED. Patients rated the intensity of their pain on a 100-mm visual analog scale (VAS) at baseline; 30, 60, 90, 120, and 180 minutes; and 24 and 48 hours after treatment. Telephone follow-up was obtained at 24 and 48 hours, and side effects were elicited at 24 and 48 hours by means of open-ended questioning. Results: The patients in each group were similar with regard to diagnosis and baseline pain score. The number of patients who did not complete the protocol and the number of those who required additional analgesia were similar in both groups. Over the 48 hours of the protocol, the mean VAS score for the combination group decreased from 60.4 to 35.6, and the mean VAS score for the ibuprofen alone group decreased from 62.2 to 35.4. The mean VAS scores between groups across time was not statistically significant (P=.962, repeated-measures analysis of variance). At both 24 and 48 hours, central nervous system side effects were reported more frequently in the patients receiving cyclobenzaprine (16 [42%] versus 7 [18%] at 24 hours and 15 [39%] versus 5 [13%] at 48 hours, respectively). Conclusion: In ED patients with acute myofascial strain, the addition of cyclobenzaprine to ibuprofen does not improve analgesia but is associated with a greater prevalence of central nervous system side effects.

Study objectives: Musculoskeletal spasm and pain is a leading cause of physician visits and a frequent cause of disability in people younger than 45 years. Many patients with musculoskeletal spasm and pain are treated only with high doses of nonsteroidal anti-inflammatory drugs (NSAIDs) without muscle relaxants. There are few published studies comparing the efficacy of a muscle relaxant alone or in combination with NSAIDs to support a specific treatment regimen. We are conducting a community-based trial comparing cyclobenzaprine 5 mg (Flexeril 5 mg) administered 3 times daily (tid) alone (Cyc5) or in combination with ibuprofen 400 mg tid (Motrin-IB; Cyc5/Ibu400) or ibuprofen 800 mg tid (Cyc5/Ibu800) to determine whether either over-the-counter or prescription doses of NSAIDs improve treatment outcomes when used in combination with a muscle relaxant. In 2 previous double-blind studies of acute muscle pain, cyclobenzaprine 5 mg tid alone was shown to have efficacy equivalent to 10 mg tid and superior to placebo, and to have fewer adverse events (principally sedation and dry mouth). We test the hypothesis that cyclobenzaprine 5 mg tid plus ibuprofen (400 or 800 mg tid) is not superior to cyclobenzaprine 5 mg tid alone in the treatment of acute muscle spasm and pain. Methods: This was a prospective, randomized, open-label, multicenter, 7-day study of Cyc5 versus Cyc5/Ibu400 or Cyc5/Ibu800 in patients with acute muscle spasm of the back or neck of 14 days' duration or less. Patients' spasm and pain were assessed using an 11-point (0 to 10) patient-rated numeric pain rating score collected by an interactive voice recognition system after 3 and 7 days of therapy. Patients were men and women aged 18 to 65 years. Results: Interim data from 316 patients with acute muscle spasm and pain who completed up to 7 days of therapy (Cyc5, n=102; Cyc5/Ibu400, n=115; Cyc5/Ibu800, n=99) were assessed at baseline and after 3 days (D3) and 7 days (D7) of therapy. The percentages of changes from baseline for muscle spasm and pain scores were as follows: spasm score changes: Cyc5: –35% D3; –55% D7; Cyc5/Ibu400: –37% D7; –59% D7; and Cyc5/Ibu800: –35% D3; –57% D7; and pain score changes: Cyc5: –32% D3; –52% D7; Cyc5/Ibu400: –33% D3; –56% D7; and Cyc5/Ibu800: –32% D3; –53% D7. All 3 treatments had statistically significant improvements from baseline after 3 and 7 days of therapy for spasm and pain ( P P Conclusion: Preliminary results indicate that all treatment arms provide similar improvements in acute muscle spasm and pain. These findings support the hypothesis that cyclobenzaprine 5 mg tid plus ibuprofen (400 or 800 mg tid) is not superior to cyclobenzaprine 5 mg tid alone in the treatment of acute muscle spasm and pain.

A case of cyclobenzaprine (Flexeril ® ) overdose in a 31-year-old woman is presented. The treatment rendered was analogous to treatment protocols implemented for tricyclic overdose. A review of the pharmacology of cyclobenzaprine, as well as the management of patients who overdose on this drug, is presented.