Q: Does topical diclofenac relieve osteoarthritis pain? Evidence-based answer: Yes, at least in the short term. Topical diclofenac, with and without dimethyl sulfoxide (DMSO), modestly improves pain and function scores (by 4%-8%) for as long as 12 weeks in patients with osteoarthritis (OA) of the knee (strength of recommendation [SOR]: A, meta-analyses of multiple randomized controlled trials [RCTs]). Topical diclofenac modestly decreases pain scores in patients with OA of the hand in the short term (by 9% at 6 weeks) but no more than placebo at 8 weeks (SOR: B, RCT). Both topical diclofenac with DMSO and oral diclofenac produce similar pain and function scores in patients with OA of the knee. In addition to minor skin dryness, topical diclofenac causes gastrointestinal (GI) adverse effects in about a third of patients (SOR: B, RCT)