Flexible dosed duloxetine in the treatment of fibromyalgia: a randomized, double-blind, placebo-controlled trial.
OBJECTIVE
To investigate the efficacy of flexible dose duloxetine 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.


CONCLUSIONS
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).
Arnold
Lesley M
LM
Women’s Health Research Program, Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Clauw
Daniel
D
Wang
Fujun
F
Ahl
Jonna
J
Gaynor
Paula J
PJ
Wohlreich
Madelaine M
MM
D000328:Adult; D004311:Double-Blind Method; D000068736:Duloxetine Hydrochloride; D005260:Female; D005356:Fibromyalgia / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D010919:Placebos; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013876:Thiophenes / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome
D000068736:Duloxetine Hydrochloride; D010919:Placebos; D017367:Selective Serotonin Reuptake Inhibitors; D013876:Thiophenes