This randomized, double-blind, placebo-controlled study assessed efficacy and safety
of duloxetine in patients with chronic low back pain (CLBP). Adults (n = 401) with
a nonneuropathic CLBP and average pain intensity of ≥ 4 on an 11-point numerical scale
(Brief Pain Inventory [BPI]) were treated with either duloxetine 60 mg once daily
or placebo for 12 weeks. The primary measure was BPI average pain. Secondary endpoints
included Patient's Global Impressions of Improvement (PGI-I), Roland Morris Disability
Questionnaire (RMDQ-24), BPI-Severity (BPI-S), BPI-Interference (BPI-I), and response
rates (either ≥ 30% or ≥ 50% BPI average pain reduction at endpoint). Health outcomes
included Short Form-36, European Quality of Life-5 Dimensions, and the Work Productivity
and Activity Impairment questionnaire. Safety and tolerability were assessed. Compared
with placebo-treated patients, duloxetine-treated patients reported a significantly
greater reduction in BPI average pain (P ≤ .001). Similarly, duloxetine-treated patients
reported significantly greater improvements in PGI-I, BPI-S, BPI-I, 50% response rates,
and some health outcomes. The RMDQ and 30% response rate showed numerical improvements
with duloxetine treatment. Significantly more patients in the duloxetine group (15.2%)
than patients in the placebo group (5.4%) discontinued because of adverse events (P
= .002). Nausea and dry mouth were the most common treatment-emergent adverse events
with rates significantly higher in duloxetine-treated patients.
This study provides clinical evidence of the efficacy and safety of duloxetine at
a fixed dose of 60 mg once daily in the treatment of chronic low back pain (CLBP).
As of December 2009, duloxetine has not received regulatory approval for the treatment
of CLBP.
Copyright © 2010 American Pain Society. Published by Elsevier Inc. All rights reserved.