The primary objective of this study is to review the efficacy of
duloxetine in treating
chronic pain using the Initiative on Methods, Measurement, and
Pain Assessment in Clinical Trials (IMMPACT) recommendations for clinical significance across
chronic pain states. These include
pain intensity, patient ratings of overall improvement, physical functioning, and mental functioning. This review comprised the side-by-side analyses of 12 double-blind, placebo-controlled trials of
duloxetine in patients with
chronic pain (diabetic peripheral
neuropathic pain,
fibromyalgia,
chronic pain due to
osteoarthritis, and chronic
low back pain). Patients received
duloxetine (60 to 120 mg/day) or placebo. Average
pain reduction was assessed over 3 months as the primary efficacy outcome. Other measures used were physical function and Patient Global Impression of Improvement. In 10 of the 12 studies, statistically significant greater
pain reduction was observed for
duloxetine- compared with placebo-treated patients. The response rates based on average
pain reduction, improvement of physical function, and global impression were comparable across all 4
chronic pain states. Compared with patients on placebo, significantly more patients treated with
duloxetine reported a moderately important
pain reduction (≥30% reduction) in 9 of the 12 studies, a minimally important improvement in physical function in 8 of the 12 studies, and a moderately important to substantial improvement in Patient Global Impression of Improvement rating in 11 of the 12 studies. The analyses reported here show that
duloxetine is efficacious in treating
chronic pain as demonstrated by significant improvement in
pain intensity, physical functioning, and patient ratings of overall improvement.