Topical rubefacients for acute and chronic pain in adults

 

Abstract

Background

Rubefacients (containing salicylates or nicotinamides) cause irritation of the skin, and are believed to relieve various musculoskeletal pains. They are available on prescription, and are common components in over-the-counter remedies. A non-Cochrane review in 2004 found limited evidence for efficacy.

Objectives

To review current evidence for efficacy and safety of topically applied rubefacients in acute and chronic painful musculoskeletal conditions in adults.

Search methods

Cochrane CENTRAL, MEDLINE, EMBASE, the Oxford Pain Relief Database, and reference lists of articles were searched; last search December 2008.

Selection criteria

Randomised, double blind, placebo or active controlled clinical trials of topical rubefacient for musculoskeletal pain in adults, with at least 10 participants per treatment arm, and reporting outcomes at close to 7 (minimum 3, maximum 10) days for acute conditions and 14 (minimum 7) days or longer for chronic conditions.

Data collection and analysis

Two review authors independently assessed trials for inclusion and quality, and extracted data. Relative benefit or risk and number needed to treat to benefit or harm (NNT or NNH) were calculated with 95% confidence intervals (CI). Acute and chronic conditions were analysed separately.

Main results

Six placebo and one active controlled studies (560 and 137 participants) in acute pain, and seven placebo and two active controlled studies (489 and 90 participants) in chronic pain were included. All used topical salicylates. The evidence in acute conditions was not robust; using only better quality, valid studies, there was no difference between topical rubefacient and topical control, though overall, including lower quality studies, the NNT for clinical success compared with placebo was 3.2 (95% CI: 2.4 to 4.9). In chronic conditions the NNT was 6.2 (95% CI: 4.0 to 13) compared with topical placebo. Adverse events and withdrawals occurred more often with rubefacients than placebo, but analyses were sensitive to inclusion of individual studies, so not robust. There were insufficient data to draw conclusions against active controls.

Authors' conclusions

The evidence does not support the use of topical rubefacients containing salicylates for acute injuries, and suggests that in chronic conditions their efficacy compares poorly with topical non-steroidal antiinflammatory drugs (NSAIDs). Topical salicylates seem to be relatively well tolerated in the short-term, based on limited data. There is no evidence at all for topical rubefacients with other components.

 

Plain language summary

Topical rubefacients for acute and chronic musculoskeletal pain in adults

Rubefacients cause irritation and reddening of the skin, due to increased blood flow. They are believed to relieve pain in various musculoskeletal conditions, and are available on prescription and in over-the-counter remedies. This review found evidence that was limited by the quality, validity and size of the available studies, particularly for studies in acute pain conditions like strains and sprains, where there was inadequate information to support the use of rubefacients. In chronic pain conditions such as osteoarthritis the evidence was more robust, but rubefacients appear to provide useful levels of pain relief in one in six individuals over and above those who also responded to placebo. This compares poorly with topical NSAIDs where substantial amounts of good quality evidence indicate that one in every three individuals treated will experience useful levels of pain relief over and above those who also responded to placebo.

 

摘要

背景

局部使用辣椒素(rubefacients)於成人急性或是慢性疼痛的控制

辣椒素(含水楊酸或菸鹼胺)可以造成皮膚的刺激，咸信可以減緩各種肌肉骨骼的疼痛。在處方藥和成藥當中都有這種成分，一篇2004年的nonCochrane回顧研究中發現有限的證據證明它的效果。

目標

回顧目前關於成人局部使用辣椒素，用於急性及慢性骨骼肌肉疼痛之有效性和安全性的證據

搜尋策略

搜尋到2008年12月為止，列於Cochrane CENTRAL, MEDLINE, EMBASE, the Oxford Pain Relief Database資料庫的文章。

選擇標準

隨機分派、雙盲、安慰劑或比較試劑的控制臨床試驗，使用局部辣椒素用於成人骨骼肌肉疼痛的研究。每一組至少有10個參與者，而且急性疼痛追蹤約7天(3天到10天)，慢性疼痛追蹤約14天(最少7天)。

資料收集與分析

兩位評論作者個別分析試驗的結論及品質和摘錄數據，以95%信賴區間來計算相對利益或風險、益一需治數或害一需治數。急性和慢性疼痛是分開來分析的。

主要結論

急性疼痛的研究方面，共有6個安慰劑試驗和一個比較試驗(分別是560個和137個參與者)；慢性疼痛方面，有7個安慰劑試驗和兩個比較試驗(分別是489個和90個參與者)。全部是使用局部水楊酸。若只使用品質和效度較好的研究，對於急性疼痛的證據並不顯著，局部使用辣椒素和對照組並沒有統計學上的顯著差別，若連品質較低的試驗也包含進來計算，益一需治數和安慰劑比較起來是3.2(95%信賴區間2.4 to 4.9)。用在慢性疼痛的益一需治數和安慰劑比較起來是6.2(95%信賴區間4.0 to 13)，辣椒素和安慰劑比較，較常發生副作用和反彈反應，但是經過分析之後證據並不強烈。沒有足夠的證據來做出反對比較試驗的結論。

作者結論

目前證據上並不支持局部使用含水楊酸的辣椒素來治療急性疼痛，也不建議用於慢性疼痛上，它的效果並不比非類固醇止痛藥有效。以目前有限的資料看來，短期使用局部水楊酸似乎有較佳的耐受度。關於局部使用辣椒素和其他成份比較起來並沒有任何證據顯示其優劣。

翻譯人

本摘要由臺北榮民總醫院李國瑋翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

辣椒素因增加血流來使皮膚刺激和發紅，一般認為它可以減少骨骼肌肉不同程度的疼痛，在一般的處方藥和成藥中都含有這種成分。這篇回顧因受限於可得到的研究品質、效度和規模，特別是用於急性的拉傷和扭傷，所以並沒有足夠的證據支持辣椒素的使用。對於如關節炎的慢性疼痛，證據就比較強烈了，但是辣椒素和安慰劑比較起來對於至少有六分之一的人有效，而他們對於安慰劑也有反應。局部非類固醇止痛藥在大量良好品質的證據中指出，至少每三分之一但安慰劑也有反應的病患可以得到有效的疼痛緩解，此結果相較於局部辣椒素，局部辣椒素的結果還是較差。