A Double-blind, Randomized, Placebo-controlled Study of the Efficacy and Safety of Duloxetine for the Treatment of Chronic Pain Due to Osteoarthritis of the Knee

• Published in: Pain practice Vol. 11; no. 1; pp. 33 - 41
• Main Authors: Chappell, Amy S., Desaiah, Durisala, Liu-Seifert, Hong, Zhang, Shuyu, Skljarevski, Vladimir, Belenkov, Yuri, Brown, Jacques P.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.01.2011
• Subjects: acute phase therapy; Aged; Analgesics - therapeutic use; Chronic Disease; chronic pain; Clinical trials; Constipation; Double-Blind Method; Duloxetine; Duloxetine Hydrochloride; Female; Humans; Inventories; Knee; Male; Middle Aged; Nausea; Osteoarthritis; osteoarthritis of the knee; Osteoarthritis, Knee - complications; Osteoarthritis, Knee - drug therapy; Pain; Pain - drug therapy; Pain - etiology; Pain Measurement; Physical training; Severity of Illness Index; Thiophenes - therapeutic use; Time Factors; Treatment Outcome
• DOI: 10.1111/j.1533-2500.2010.00401.x
• ISSN: 1530-7085; 1533-2500

Objective:  To evaluate the efficacy and safety of duloxetine in the treatment of chronic pain due to osteoarthritis of the knee. Methods:  This was a 13‐week, randomized, double‐blind, placebo‐controlled trial in patients meeting American College of Rheumatology clinical and radiographic criteria for osteoarthritis of the knee. At baseline, patients were required to have a ≥ 4 weekly mean of the 24‐hour average pain ratings. Patients were randomized to either duloxetine 60 mg once daily (QD) or placebo. At week 7, the duloxetine dosage was increased, in a blinded fashion, to 120‐mg QD in patients reporting < 30% pain reduction. The primary efficacy measure was Brief Pain Inventory (BPI) 24‐hour average pain. Secondary efficacy measures included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); Clinical Global Impressions of Severity (CGI‐S). Safety and tolerability was also assessed. Results:  Of the total (n = 256) patients, 111 (86.7%) in placebo group and 93 (72.7%) in duloxetine group completed the study. Patients treated with duloxetine had significantly (P ≤ 0.001) greater improvement at all time points on BPI average pain and had significantly greater improvement on BPI pain severity ratings (P ≤ 0.05), WOMAC total (P = 0.044) and physical functioning scores (P = 0.016), and CGI‐S (P = 0.009) at the study endpoint. Frequency of treatment‐emergent nausea, constipation, and hyperhidrosis were significantly higher in the duloxetine group (P ≤ 0.05). Significantly more duloxetine‐treated patients discontinued the trial because of adverse events (P = 0.002). Conclusions:  Treatment with duloxetine 60 mg to 120 mg QD was associated with significant pain reduction and improved function in patients with pain due to osteoarthritis of the knee.