Topical analgesics effective for acute and chronic pain

For strains and sprains, several topical non-steroidal anti-inflammatory drugs (NSAIDs) helped reduce pain by at least half over about a week (NNT* 2–5). These were diclofenac Emulgel, ketoprofen gel, piroxicam gel, diclofenac Flector plaster and diclofenac other plaster. For hand and knee osteoarthritis, topical diclofenac and topical ketoprofen reduced pain by at least half over at least 6–12 weeks (NNT* 5–10). For postherpetic neuralgia, a single application of topical high-concentration capsaicin reduced pain by at least half for 8–12 weeks (NNT* 12). There was no good evidence to support any other topical analgesic in any other painful condition. Topical low-concentration capsaicin caused local side effects (such as itching or rash) in 40% of patients, and side effects caused withdrawal in just over 8%. Side effects and withdrawal because of side effects were otherwise uncommon or not different from those with a topical placebo. Serious side effects were uncommon.

*NNT = number needed to treat to benefit 1 individual.