A Double-Blind Crossover Study of Two Cyclobenzaprine Regimens in Primary Fibromyalgia Syndrome

Abstract

In a double-blind crossover study, the efficacy and tolerability of oral cyclobenzaprine administered in two different regimens were compared in 40 patients affected by primary fibromyalgia syndrome. The patients were randomly divided into two groups. Each group of 20 patients was treated for 15 days with either a single dose of 10 mg/day cyclobenzaprine at bedtime or 30 mg/day cyclobenzaprine in three equal doses daily. Following treatment there was a 15-day washout period before the groups were crossed over to the other treatment. Both regimens resulted in a significant decline in the number of tender points; significant improvements were also reported in the quality of sleep, anxiety, fatigue, irritable bowel syndrome and stiffness. There was no significant difference in efficacy between the two therapeutic regimens at any stage during the trial. The frequency of reported side-effects was significantly greater (P < 0.001) when patients received 30 mg/day cyclobenzaprine (26 patients, 84%) than when they received 10 mg/day (10 patients, 27%). A dose of 10 mg cyclobenzaprine at bedtime significantly improved the symptomatology of patients affected by primary fibromyalgia syndrome. The higher dose did not further reduce these symptoms but did result in a higher incidence of side-effects.

Interdisciplinary treatment for fibromyalgia syndrome: Clinical and statistical significance

“…Of these patients, 70 (92%) completed the program. Of the 6 patients who terminated treatment prematurely, 3 reported they were dissatisfied with the program, one reported exacerbation of pain, and no clear reasons were cited by two. Of the 70 patients who completed the treatment program, 3 were excluded from the analyses due to missing data; thus, the present study included 67 FMS patients.…”

“…The program was an outpatient group rehabilitation program that consisted of 6 one-half-day sessions, spaced over a period of 4 weeks. Groups of [4][5][6][7] patients attended the program 3 times a week during the first week and once a week for the next 3 weeks.…”

“…For the patients who did not respond to the treatment for pain relief, Predictors of treatment success. From the accumulated empirical research in FMS and other types of chronic pain, a set of 6 variables was considereti most important in reports of pain severity in FMS: pretreatment levels of pain severity, depression (CES-D), activity (MPI), solicitous responses of others (MPI), and perceived disability (ODI), and a dichotomous variable (pain onset, idiopathic versus identifiable onset) (37,38). Of 67 patients, complete data were available for 56 (22 responders, 34 nonrcsponders).…”

“…Approximately [3][4][5][6] million Americans are estimated to be affected by this syndrome (12) A number of pharmacologic interventions have been evaluated to determine their effectiveness in treating FMS. Tricyclic antidepressants (3,4), nonsteroidal anti-inflammatory drugs (NSAIDs) (5), and muscle relaxants (6) have been the primary focus of clinical trials. The results of these studies are difficult to synthesize because of the diversity in the variables, outcome criteria, and measurement instruments used (7).…”

Management of Fibromyalgia Syndrome

“…Cyclobenzaprine is chemically close to amitriptyline although it is used as a muscle relaxant with no expected antidepressant effects. The use of cyclobenzaprine resulted in improvement in pain, sleep and fatigue in FM patients [25,26]. Recently, a multi-centered Phase II trial evaluating a small dose sublingual cyclobenzaprine for 12 weeks [27] showed promising benefit for FM and sleep symptoms relative to placebo.…”