Objective: To investigate the efficacy of flexible dose duloxetine [trade name Cymbalta] 60-120 mg/day on changes in fibromyalgia (FM) symptoms assessed by the Patient Global Impression of Improvement (PGI-I) scale.
Methods: Outpatients ? 18 years of age who met American College of Rheumatology criteria for FM, and had ? 4 score on the Brief Pain Inventory (BPI) average pain item, were randomized to duloxetine (n = 263) or placebo (n = 267) for 24 week double-blind treatment (primary endpoint at Week 12).
Key secondary measures included BPI average pain severity, patient-rated scales assessing mood, anxiety, pain, sleep, and stiffness, Clinical Global Impression of Severity (CGI-S), Multidimensional Fatigue Inventory, Cognitive and Physical Functioning Questionnaire, Beck Depression Inventory (BDI), Beck Anxiety Inventory, and Medical Outcome Study Short-Form Health Survey (SF-36).
Results: At Week 12, duloxetine-treated patients reported significantly greater global improvement with mean PGI-I scores of 2.8 compared to 3.4 in the placebo group (p < 0.001).
Significantly more duloxetine-versus placebo-treated patients (57% vs 32%; p < 0.001) reported feeling "much" or "very much better" (PGI-I score ? 2). There was significantly greater improvement with duloxetine versus placebo treatment in BPI average pain severity, mood (including BDI total), anxiety (patient-rated only), stiffness, CGI-S, fatigue, all SF-36 domains (except role-physical and physical component summary), and being less bothered by pain or sleep difficulties.
Treatment-emergent adverse events occurring significantly more frequently with duloxetine included: nausea, headache, constipation, dry mouth, dizziness, diarrhea, and hyperhidrosis [excessive unpredictable sweating].
Conclusion: Treatment with duloxetine 60, 90, and 120 mg/day was associated with feeling much better, pain reduction, being less bothered by sleep difficulties, and improvement in mood, stiffness, fatigue and functioning. (Clinical trial registry NCT00673452).
Source: Journal of Rheumatology, Sep 15, 2010. PMID: 20843911, by Arnold LM, Clauw D, Wang F, Ahl J, Gaynor PJ, Wohlreich MM. From the Women' s Health Research Program, Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, Ohio; Department of Anesthesiology, Chronic Pain and Fatigue Research Center , University of Michigan Medical Center , Ann Arbor , Michigan; Lilly USA, LLC, Indianapolis, Indiana, USA.