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Topical capsaicin (high concentration) for chronic neuropathic pain in adults

  1. Sheena Derry1,*,
  2. Andrew S C Rice2,3,
  3. Peter Cole4,
  4. Toni Tan5,
  5. R Andrew Moore1

Editorial Group: Cochrane Pain, Palliative and Supportive Care Group

Published Online: 28 FEB 2013

Assessed as up-to-date: 10 DEC 2012

DOI: 10.1002/14651858.CD007393.pub3


How to Cite

Derry S, Rice ASC, Cole P, Tan T, Moore RA. Topical capsaicin (high concentration) for chronic neuropathic pain in adults. Cochrane Database of Systematic Reviews 2013, Issue 2. Art. No.: CD007393. DOI: 10.1002/14651858.CD007393.pub3.

Author Information

  1. 1

    University of Oxford, Pain Research and Nuffield Department of Clinical Neurosciences, Oxford, Oxfordshire, UK

  2. 2

    Imperial College London, Pain Research, Department of Surgery and Cancer, Faculty of Medicine, London, UK

  3. 3

    Chelsea and Westminster Hospital NHS Foundation Trust, Department of Pain Medicine, London, UK

  4. 4

    Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford Pain Relief Unit, Oxford, UK

  5. 5

    National Institute for Health and Clinical Excellence, Centre for Clinical Practice, Manchester, UK

*Sheena Derry, Pain Research and Nuffield Department of Clinical Neurosciences, University of Oxford, Pain Research Unit, Churchill Hospital, Oxford, Oxfordshire, OX3 7LE, UK. sheena.derry@ndcn.ox.ac.uk.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 28 FEB 2013

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Résumé scientifique
  5. Résumé simplifié
  6. Laički sažetak

Background

Topical creams with capsaicin are used to treat peripheral neuropathic pain. Following application to the skin capsaicin causes enhanced sensitivity, followed by a period with reduced sensitivity and, after repeated applications, persistent desensitisation. High-concentration (8%) capsaicin patches were developed to increase the amount of capsaicin delivered; rapid delivery was thought to improve tolerability because cutaneous nociceptors are 'defunctionalised' quickly. The single application avoids noncompliance. Only the 8% patch formulation of capsaicin is available, with a capsaicin concentration about 100 times greater than conventional creams.

High-concentration topical capsaicin is given as a single patch application to the affected part. It must be applied under highly controlled conditions, normally under local anaesthetic, due to the initial intense burning sensation it causes. The benefits are expected to last for about 12 weeks, when another application might be made.

Objectives

To review the evidence from controlled trials on the efficacy and tolerability of topically applied, high-concentration (8%) capsaicin in chronic neuropathic pain in adults.

Search methods

We searched CENTRAL, MEDLINE, EMBASE and clinicaltrials.gov to December 2012.

Selection criteria

Randomised, double-blind, placebo-controlled studies of at least six weeks' duration, using topical capsaicin to treat neuropathic pain.

Data collection and analysis

Two review authors independently assessed trial quality and validity, and extracted data on numbers of participants with pain relief (clinical improvement) after at least six weeks, and with local skin reactions. We calculated risk ratio and numbers needed to treat to benefit (NNT) and harm (NNH). We sought details of definition of pain relief and specific adverse events.

Efficacy outcomes reflecting long-duration pain relief after a single drug application were from the patient global impression of change (PGIC) at specific points, usually eight and 12 weeks. We regarded these outcomes as first-tier evidence. We regarded average pain scores over weeks 2 to 8 and 2 to 12 and the number and/or percentage of participants with pain intensity reduction of at least 30% or at least 50% over baseline as second-tier evidence.

Main results

We included six studies, involving 2073 participants; they were of generally good reporting quality; the control was 0.04% topical capsaicin to help maintain blinding. Efficacy outcomes were inconsistently reported between studies, however, resulting in analyses for most outcomes being based on less than complete data.

Four studies involved 1272 participants with postherpetic neuralgia. All efficacy outcomes were significantly better than control. At both eight and 12 weeks there was a significant benefit for high-concentration over low-concentration topical capsaicin for participants reporting themselves to be much or very much better, with point estimates of the NNTs of 8.8 (95% confidence interval (CI) 5.3 to 26) and 7.0 (95% CI 4.6 to 15) respectively. More participants had average 2 to 8-week and 2 to 12-week pain intensity reductions over baseline of at least 30% and at least 50% with active treatment than control, with NNT values between 10 and 12.

Two studies involved 801 participants with painful HIV-neuropathy. In a single study the NNT at 12 weeks for participants to be much or very much better was 5.8 (95% CI 3.8 to 12). Over both studies more participants had average 2 to 12-week pain intensity reductions over baseline of at least 30% with active treatment than control, with an NNT of 11.

Local adverse events were common, but not consistently reported. Serious adverse events were no more common with active treatment (4.1%) than control (3.2%). Adverse event withdrawals did not differ between groups, but lack of efficacy withdrawals were somewhat more common with control than active treatment, based on small numbers of events. No deaths were judged to be related to study medication.

Authors' conclusions

High-concentration topical capsaicin used to treat postherpetic neuralgia and HIV-neuropathy generates more participants with high levels of pain relief than does control treatment using a much lower concentration of capsaicin. The additional proportion who benefit over control is not large, but for those who do obtain high levels of pain relief there are additional improvements in sleep, fatigue, depression and an improved quality of life. High-concentration topical capsaicin is therefore similar to other therapies for chronic pain. In this case, the high cost of single and repeated applications suggest that high-concentration topical capsaicin is likely to be used when other available therapies have failed, and that it should probably not be used repeatedly without substantial documented pain relief. Even when efficacy is established, there are unknown risks, especially on epidermal innervation, of repeated application of long periods.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Résumé scientifique
  5. Résumé simplifié
  6. Laički sažetak

Capsaicin applied to the skin for chronic neuropathic pain in adults

Neuropathic pain is caused by damage to nerves, either from injury or disease. Pain is described as chronic if it has been experienced on most days for at least three months. Capsaicin is what makes chilli peppers hot. It is thought to reduce chronic neuropathic pain by making nerves insensitive to pain messages. This review is about a highly concentrated preparation of capsaicin (8%) that has to be administered in carefully controlled conditions in a clinic or hospital, under local anaesthetic, because without special precautions it can cause pain and burning of the skin. The single application is designed to produce relief of pain for up to three months.

In six studies with 2073 participants, we found evidence that the treatment worked in two types of neuropathic pain, pain after shingles, and nerve injury pain associated with HIV infection. About 1 person in 8 who receives the treatment will get good pain relief. Those who do not will probably not receive the treatment again, while those who do might have the treatment several times a year.

In all people who have this treatment there can be short-lived localised skin problems like redness (erythema), burning, or pain, but serious problems seem to be uncommon and no more frequent in these trials with high-concentration capsaicin than with the control treatment using very low-concentration capsaicin. We do not know whether repeated treatments will give the same efficacy, or what effect they may have on the skin.

 

Résumé scientifique

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Résumé scientifique
  5. Résumé simplifié
  6. Laički sažetak

Capsaïcine topique pour la douleur neuropathique chronique chez l'adulte

Contexte

Les crèmes topiques contenant de la capsaïcine sont utilisées pour traiter la douleur associée à un large éventail de troubles chroniques, notamment la douleur neuropathique. Une fois appliquée sur la peau, la capsaïcine entraîne une augmentation de la sensibilité aux stimuli nocifs, suivie d'une période de sensibilité réduite et d'une désensibilisation durable après des applications répétées. L'efficacité et la tolérance de la capsaïcine pour le traitement des neuropathies chroniques douloureuses ne sont pas clairement établies.

Objectifs

Examiner les preuves issues d'essais contrôlés portant sur l'efficacité et la tolérance de la capsaïcine en application topique pour la douleur neuropathique chronique chez l'adulte.

Stratégie de recherche documentaire

Les bases de données Cochrane CENTRAL, MEDLINE, EMBASE et l'Oxford Pain Relief Database ont été consultées en mai 2009.

Critères de sélection

Les essais randomisés en double aveugle et contrôlés par placebo d'une durée d'au moins six semaines utilisant la capsaïcine topique pour traiter la douleur neuropathique.

Recueil et analyse des données

Deux auteurs de revue ont évalué la qualité et la validité des essais et extrait les données de manière indépendante. Des informations ont été extraites concernant le nombre de participants ressentant un soulagement de la douleur (amélioration clinique) après au moins six semaines et présentant des réactions cutanées locales ; ces données ont été utilisées pour calculer le risque relatif et le nombre de sujets à traiter pour observer un bénéfice du traitement (NST) ou pour nuire (NNN). Des informations supplémentaires concernant la définition du soulagement de la douleur et les événements indésirables spécifiques ont été recherchées.

Résultats principaux

Six études (389 participants) comparaient l'application régulière d'une crème contenant une faible dose de capsaïcine (0,075 %) à une crème placebo ; le NST pour tout soulagement de la douleur pendant six à huit semaines était de 6,6 (4,1 à 17). Deux études (709 participants) comparaient une seule application d'un patch contenant une dose élevée de capsaïcine (8 %) à un patch de placebo ; le NST pour un soulagement de la douleur ≥ 30 % pendant douze semaines était de 12 (6,4 à 70). Les réactions cutanées locales étaient plus fréquentes avec la capsaïcine, étaient généralement tolérables et s'atténuaient avec le temps ; le NNN pour une application répétée à faible dose était de 2,5 (2,1 à 3,1). Les données étaient insuffisantes pour analyser l'un ou l'autre de ces ensembles de données par affection ou définition du résultat. Toutes les études étaient conformes aux critères minimums de qualité et de validité, mais le maintien de l'assignation en aveugle posait un problème potentiel.

Conclusions des auteurs

La capsaïcine, sous forme d'application répétée d'une crème à faible dose (0,075 %) ou d'application unique d'un patch à dose élevée (8 %), pourrait apporter un certain soulagement de la douleur chez certains patients atteints de neuropathie douloureuse. L'irritation cutanée locale est fréquente. Elle est souvent légère et passagère mais pourrait entraîner un arrêt prématuré. Les effets systémiques indésirables sont rares. Les estimations des bénéfices et effets délétères ne sont pas solides car les données disponibles concernant les différents troubles neuropathiques sont insuffisantes et que la définition des résultats est variable.

 

Résumé simplifié

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Résumé scientifique
  5. Résumé simplifié
  6. Laički sažetak

Capsaïcine appliquée sur la peau pour la douleur neuropathique chronique chez l'adulte

La capsaïcine topique (appliquée sur la peau) peut permettre de soulager la douleur associée à plusieurs affections neuropathiques douloureuses mais peut causer une irritation locale de la peau entraînant une sensation de brûlure ou de démangeaison. Le niveau de soulagement de la douleur ressenti par les patients est incertain en raison des différentes définitions utilisées dans ces études. La fiabilité de l'estimation du nombre d'individus pouvant potentiellement bénéficier de ce traitement est limitée car le nombre de participants était insuffisant et que les réponses variaient probablement pour les différentes affections neuropathiques. La capsaïcine seule ou combinée à un autre traitement pourrait s'avérer utile pour soulager la douleur des patients qui ne répondent pas aux autres traitements disponibles ou ne les tolèrent pas.

Notes de traduction

Traduit par: French Cochrane Centre 5th March, 2013
Traduction financée par: Ministère du Travail, de l'Emploi et de la Santé Français

 

Laički sažetak

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Résumé scientifique
  5. Résumé simplifié
  6. Laički sažetak

Primjena kapsaicina na kožu kod kronične neuropatske boli u odraslih

Neuropatska bol uzrokovana je oštećenjem živaca, bilo od ozljede ili bolesti. Bol se opisuje kao kronična ako je prisutna većinu dana tijekom najmanje tri mjeseca. Kapsaicin je tvar koja feferone čini ljutima. Smatra se da smanjuje kroničnu neuropatsku bol čineći živce neosjetljivima na bolne podražaje. Ovaj pregledni članak prikazuje vrlo koncentrirani pripravak kapsaicina (8%) koji mora biti primijenjen u pomno kontroliranim uvjetima u klinici ili bolnici, pod lokalnom anestezijom, jer bez posebnih mjera opreza može uzrokovati bol i žarenje na koži. Jedno nanošenje je namijenjeno za nastanak olakšanja bolova u trajanju do tri mjeseca.

U šest studija s 2.073 sudionika, pronašli smo dokaze da je liječenje pomagalo u dvije vrste neuropatske boli, odnosno boli nakon herpesa zostera i boli zbog ozljede živaca povezane s HIV infekcijom. Otprilike će 1 osoba od 8 koje su primile ovo liječenje imati dobro olakšanje boli. One koje neće vjerojatno neće ponovno biti liječene ovim pripravkom, a kod onih koji hoće liječenje se može ponoviti nekoliko puta godišnje.

Kod svih ljudi koji prime ovo liječenje mogu se javiti kratkotrajne lokalizirane kožne tegobe kao što su crvenilo (eritem), žarenje ili bol, ali ozbiljne tegobe čine se manje česte odnosno ne češće u ovim ispitivanjima visoke koncentracije kapsaicina nego kod kontrolnog liječenja u kojem se primjenjivala vrlo niska koncentracija kapsaicina. Ne znamo hoće li ponovljeni tretmani pokazati istu djelotvornost, ili kakav učinak mogu imati na koži.

Bilješke prijevoda

Prevoditelj:: Croatian Branch of the Italian Cochrane Centre