The quality of evidence is downgraded by study limitations (lack of/unclear allocation concealment and imprecise results).
In a Cochrane review [Abstract] 1 six studies (with 389 participants) compared topically applied low dose (< 1.0%) capsaicin cream with placebo cream, applied regularly several times daily over several weeks, in chronic neuropathic pain in adults. All included studies were published before 1996. Only two studies reported data for the preferred primary outcome of at least 50% pain relief, and there were too few data for pooled analysis.
Local skin reactions were more common with capsaicin, usually tolerable, and attenuated with time; the NNH for repeated low-dose application was 2.5 (95% CI 2.1 to 3.1).
| Outcome | Number of participants (trials) | Control:Placebo | Intervention:Capcaicin | Effect size (95 % CI) |
|---|---|---|---|---|
| Pain relief > 50% | 124(2) | 8/61(13%) | 18/63(29%) | NA |
| Adverse event: burning, stinging, erythema | 557(5) | 66/275(24%) | 179/282(64%) | RR 2.64(2.10 to 3.31) |
It is unlikely that topical (rubbed on the skin), low-concentration (< 1%) capsaicin provides any useful pain relief in neuropathic pain conditions.
Date of latest search: 30.06.2012
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