Onset of response with duloxetine treatment in patients with osteoarthritis knee pain and chronic low back pain: a post hoc analysis of placebo-controlled trials.

Background: Knowing when to change pain-medication strategy is not well researched and remains a gap in treating chronic pain.

Objective: Our aim was to determine how long to treat osteoarthritis (OA) knee pain and chronic low back pain (CLBP) with duloxetine before considering a change in medication strategy.

Methods: We employed a post hoc analysis of changes in pain-severity data from placebo-controlled studies of duloxetine treatment in nondepressed patients with OA knee pain and CLBP.