High-concentration Capsaicin Patch Research Articles

Is there a role for capsaicin in cancer pain management?

Advances in oncological therapies have resulted in an increase in the number of patients living with and beyond cancer. The personal and societal impact of chronic pain in the survivor population represents an area of significant unmet need. Capsaicin (a TRPV1 agonist) may provide analgesia with limited systemic side effects. This review looks to summarise the most recent evidence regarding the use of capsaicin in the management of cancer pain. Various international guidelines have recently endorsed the use of high concentration capsaicin patches in the treatment of chronic painful chemotherapy induced peripheral neuropathy. Numerous studies support the use of capsaicin in the treatment of peripheral neuropathic pain. This promising data is predominantly yielded from pain secondary to herpes zoster and diabetic neuropathy, with an expanding but small evidence base for its utility in other neuropathic pains. Emerging data suggests that treatments are better tolerated and provide analgesia more rapidly when compared with systemic treatments. Whilst randomised controlled trial data in the treatment of cancer pain are lacking, recent large cohort studies, and international guidelines, support the use of high concentration capsaicin patches in a wide variety of neuropathic pain secondary to cancer treatments.

Neuropathic pain: Evidence based recommendations

Neuropathic pain continues to be a significant problem that lacks effective solutions for every single patient. In 2015, international guidelines (NeuPSIG) were published, while the French recommendations were updated in 2020. The purpose of this minireview is to provide an update on the process of developing evidence-based recommendations and explore potential changes to the current recommendations. Primary treatments for neuropathic pain include selective serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine and venlafaxine, gabapentin, tricyclic antidepressants, as well as topical lidocaine and transcutaneous electrical nerve stimulation, which are specifically suggested for focal peripheral neuropathic pain. Pregabalin is a first line treatment according to international guidelines but second-line in the more recent French guidelines, due to lower efficacy seen in more recent studies and misuse risk. Additionally, tramadol, combination therapies, and psychotherapy as adjuncts are proposed second line; high-concentration capsaicin patches, and botulinum toxin A are proposed specifically for focal peripheral neuropathic pain. In cases where primary and secondary treatments prove insufficient, third-line options come into play. These include high-frequency repetitive transcranial magnetic stimulation (rTMS) targeting the motor cortex, spinal cord stimulation, and the use of strong opioids when no alternative is available. To ensure optimal management of neuropathic pain in real-life situations, it is imperative to disseminate these recommendations widely and secure the acceptance of practitioners. By doing so, we can bridge the gap between theory and practice, and enhance the overall care and treatment of individuals suffering from neuropathic pain.

Characteristics and outcomes of peripheral neuropathic pain patients with repeated applications of high-concentration capsaicin cutaneous patch: Results of a retrospective chart review in Germany.

The aim of this study was to evaluate patient characteristics, concomitant analgesic medication, and pain intensity in a real-world setting in Germany, focusing on the repeated application of high-concentration capsaicin patch (HCCP) for neuropathic pain. Data were collected from electronic medical records of patients who received at least two HCCP treatments between January 2011 and July 2022. Subgroup analyses were performed based on the number of HCCP treatments, age groups, and specific neuropathic pain conditions. The study was conducted at an outpatient pain center in Wiesbaden, Germany. The study included 97 patients, primarily diagnosed with neuropathic back pain, postoperative or post-traumatic neuropathic pain, and postherpetic neuralgia. The daily dose of concomitant medications (eg, opioids and anticonvulsants) at the start of capsaicin therapy was compared with the average within 2 years of capsaicin therapy. The last observation carried forward method was used if HCCP treatment was discontinued before the end of the 2-year period. The majority of patients received concomitant medications, with opioids, anticonvulsants, and antidepressants being the most common. The average daily morphine equivalent dose decreased significantly during HCCP treatment. Pain intensity at baseline was generally high, but substantial improvements were observed in patients who received at least three HCCP applications. This study provides evidence for the effectiveness of HCCP treatment in reducing pain intensity and concomitant opioid use in patients with neuropathic pain. Further research is needed to explore the long-term outcomes and optimal treatment regimens for different patient populations.

Topical treatment of chemotherapy-induced peripheral neuropathy (CIPN) with high-concentration (179 mg) capsaicin patch in breast cancer patients - results of the QUCIP study.

Chemotherapy-induced peripheral neuropathy (CIPN) following oral or intravenous chemotherapy often results in neuropathic pain, accompanied by symptoms such tingling, burning and hypersensitivity to stimuli, with a notable decline in quality of life (QoL). Effective therapies for CIPN are lacking, with a high demand for analgesics to address this issue. The QUCIP study aimed to assess the effectiveness of high concentration (179 mg) capsaicin patch (HCCP) in alleviating neuropathic pain and associated symptoms in breast cancer patients with confirmed CIPN. QUCIP is a prospective, multi-center observational study spanning 36 weeks with up to three HCCP treatments. Initial treatment (visit V0) was followed by two telephone contacts (T1, T2) and subsequent face-to-face visits every 12 weeks or upon retreatment (visits V1-V3). 73 female patients with painful CIPN post neoadjuvant/adjuvant breast cancer therapy were enrolled. Primary endpoint was the reduction of neuropathic pain symptom score (painDETECT®). Secondary endpoints included improvements in CIPN-specific QoL (QLQ-CIPN20), reductions in pain intensity (numeric pain rating scale, NPRS), and achievement of ≥ 30% and ≥ 50% pain reduction. Median age was 61 years, with 52.0% of patients experiencing peripheral neuropathic pain for > 1 year (> 2 years: 34.2%). The painDETECT® score significantly decreased from baseline (19.71 ± 4.69) to 15.80 ± 6.20 after initial treatment (p < 0.0001) and continued to decrease at follow-up visits. The NPRS indicated significant pain intensity reduction at each time point, particularly pronounced in patients receiving three HCCP treatments. Clinically significant pain relief of ≥ 30% increased from 25.0% at week 4 (T2) to 36.2%, 43.5%, and 40.0% at weeks 12 (V1), 24 (V2), and 36 (V3), respectively. The percentage of patients achieving pain relief of ≥ 50% increased from 14.7% at T2 to 15.5%, 21.7% and 32.5% at V1, V2 and V3, respectively. Patients further reported a significant improvement in their CIPN-related QoL throughout the study. Adverse drug reactions (ADRs) mainly included application site reactions. In this study, HCCP shows benefit in managing CIPN in real-world settings. The data demonstrate a sustained and progressive reduction in neuropathic pain and symptomatology, confirming the clinical benefit of repeated treatment observed in former clinical trials. HCCP treatment has also the potential to significantly improve the QoL associated with CIPN. The safety profile of HCCP was confirmed, supporting its use in clinical practice.

Evaluation of 8% Capsaicin Patches in Chemotherapy-Induced Peripheral Neuropathy: A Retrospective Study in a Comprehensive Cancer Center.

Introduction: Chemotherapy-induced peripheral neuropathy (CIPN) is often painful and can arise during or after the end of oncological treatments. They are mostly induced by platinum salts, taxanes, and immunotherapies. Their incidence is estimated between 19 and 85%. They can require a chemotherapy dose reduction or early termination. The European Society for Medical Oncology (ESMO) recommends high-concentration capsaicin patch (HCCP) in second line for the treatment of painful CIPN. This treatment induces a significative pain relief but only shown by low-powered studies. The objective of this study was to evaluate efficacy and tolerability of HCCP applications in CIPN. Methods: This monocentric observational retrospective real-world-data study of the CERCAN cohort took place in the Western Cancer Institute's Anaesthesiology and Pain Department at Angers, France. Independent pain physicians completed the CGIC (Clinician Global Impression of Change) for each patient who benefited from HCCP applications for painful CIPN starting from 1 January 2014 to 22 December 2021, based on the collected data after every patch application. Results: A total of 57 patients (80.7% women) was treated with HCCP for painful CIPN, and 184 applications were realized, consisting of 296 sessions. CGIC found an important or complete pain relief for 61 applications (33.2%, corresponding to 43.9% patients). We found less efficacy for platinum-salts-induced CIPN compared to others (p = 0.0238). The efficacy was significatively higher for repeated applications when HCCP was used in second line compared to third line (p = 0.018). The efficacy of HCCP was significatively higher starting the third application (p = 0.0334). HCCPs were mainly responsible for local adverse events found in 66.6% patients (65.1% burning or painful sensation, 21.1% erythema). Conclusion: HCCP applications in painful CIPN induce an important pain relief with a global satisfying tolerability.

Study protocol of the TEC-ORL clinical trial: a randomized comparative phase II trial investigating the analgesic activity of capsaicin vs Laroxyl in head and neck Cancer survivors presenting with neuropathic pain sequelae

BackgroundNeuropathic pain is common in cancer survivorship and is one of the most distressing symptoms for patients previously treated for head and neck cancer. Persistent neuropathic pain, when it is ongoing and uncontrolled, has a detrimental effect and erodes patients’ quality of life. Patients treated for head and neck cancer are chronic opioid users to manage their post-treatment pain, which may entail an increased risk of addiction and overdose. We propose to evaluate the analgesic activity of high-concentration capsaicin patches for the treatment of head and neck cancer survivors presenting with neuropathic pain sequelae.MethodsTEC-ORL is a parallel, multicenter randomized comparative phase II study evaluating whether Capsaïcin patches (Qutenza®) reduce neuropathic pain when compared to Amitriptyline (Laroxyl®) in head and neck cancer survivors presenting with neuropathic pain sequelae. The primary efficacy outcome is the rate of patients with a pain reduction of at least two points at 9 months compared to baseline. Assuming that 5% of patients become lost to follow-up, 130 patients will need to be randomized to detect a 25% improvement (i.e., standard: 25%, experimental: 50%) using a one-sided chi-square test with an alpha of 0.05%. According to the recommendations for comparative phase II trials, the target differences and type I error rates are relaxed. Randomized patients will either be treated with a capsaicin 8% (Qutenza®) patch applied at three time intervals in the experimental arm or with Amitriptyline (Laroxyl®) (oral solution 40 mg/ml) taken for 9 months at the recommended daily dose of 25 mg to 75 mg in the control arm.DiscussionTEC-ORL is a randomized comparative phase II trial designed to comprehensively evaluate the analgesic activity of capsaicin compared to Laroxyl in Head and Neck Cancer survivors presenting with neuropathic pain sequelae.Trial registrationClinicalTrials.gov identifier: NCT04704453 Date of registration: 2021/01/13.

"Tolerance and Coping to High Concentration Capsaicin Patch in the Treatment of Peripheral Neuropathic Pain Using Virtual Reality: A Proof-of-Concept Project"

"Tolerance and Coping to High Concentration Capsaicin Patch in the Treatment of Peripheral Neuropathic Pain Using Virtual Reality: A Proof-of-Concept Project"

Peripheral Neuropathic Pain Following Breast Cancer: Effectiveness and Tolerability of High-Concentration Capsaicin Patch.

PurposeData supporting the use of high-concentration capsaicin patches (HCCPs) in breast cancer (BC) patients and BC survivors (BCSs) with peripheral neuropathic pain (PNP) are limited. This observational study evaluated the effectiveness and safety of HCCP applications in BCSs/BC patients with PNP.Patients and MethodsData from all patients treated with HCCP in the pain department of a French comprehensive cancer centre were collected from 01-Jan-2014 to 14-Oct-2020. Independent pain specialists completed the Clinical Global Impression of Change (CGIC) for each included patient based on data extracted from patient’s electronic medical record compiled by the treating pain specialist after each HCCP application.ResultsPatients (N=279; mean age: 59.2 years; previous history of PNP medication: 54.5%) received on average 4.1 repeated HCCP applications (1141 HCCP applications); 68.8% received HCCP as an add-on to systemic therapy and 27.9% as first-line therapy. PNP was most frequently caused by surgery (62.4%) followed by chemotherapy (11.8%) and radiotherapy (6.5%). A complete or important analgesic effect was reported at least once by 82.3% of patients. A 6.0% reported no effect at all. For post-surgical PNP existing for <12 months and >10 years an important or complete effect was observed for 70.7% and 56.0% of applications. For chemotherapy- or radiotherapy-induced PNP, this important or complete effect was observed for 52.7% and 52.3% of applications, respectively. HCCP application was associated with site reactions in 54.4% of patients (mainly burning sensation or pain, 45.9%, or erythema, 30.8%) and high blood pressure in 7.2%.ConclusionThis real-world chart review provides important effectiveness and safety information to clinicians when considering topical options to treat PNP in BCSs/BC patients.

French guidelines for neuropathic pain: An update and commentary.

Neuropathic pain remains a significant unmet need. French recommendations were updated in 2020. The goal of this minireview is to provide an update on these published guidelines. Despite newer relevant studies, our proposed algorithm remains relevant. First-line treatments include serotonin-noradrenaline reuptake inhibitors (duloxetine and venlafaxine), gabapentin and tricyclic antidepressants, topical lidocaine and transcutaneous electrical nerve stimulation being specifically proposed for focal peripheral neuropathic pain. Second-line treatments include pregabalin (such position being confirmed by newer studies), tramadol, combinations and psychotherapy as add on, high-concentration capsaicin patches and botulinum toxin A being proposed specifically for focal peripheral neuropathic pain. Third-line treatments include high-frequency repetitive transcranial magnetic stimulation of the motor cortex, spinal cord stimulation and strong opioids (in the lack of alternative). Disseminating these recommendations and ensuring that they are well accepted by French practitioners will be necessary to optimize neuropathic pain management in real life.

Modality-specific facilitation of noninjurious sharp mechanical pain by topical capsaicin.

We had previously shown that a "blunt blade" stimulator can mimic the noninjurious strain phase of incisional pain, but not its sustained duration. Here, we tested whether acute sensitization of the skin with topical capsaicin can add the sustained phase to this noninvasive surrogate model of intraoperative pain. Altogether, 110 healthy volunteers (55 male and 55 female; 26 ± 5 years) participated in several experiments using the "blunt blade" (0.25 × 4 mm) on normal skin (n = 36) and on skin pretreated by a high-concentration capsaicin patch (8%, Qutenza; n = 36). These data were compared with an experimental incision (n = 40) using quantitative and qualitative pain ratings by numerical rating scale and SES Pain Perception Scale descriptors. Capsaicin sensitization increased blade-induced pain magnitude and duration significantly (both P < 0.05), but it failed to fully match the sustained duration of incisional pain. In normal skin, the SES pattern of pain qualities elicited by the blade matched incision in pain magnitude and pattern of pain descriptors. In capsaicin-treated skin, the blade acquired a significant facilitation only of the perceived heat pain component (P < 0.001), but not of mechanical pain components. Thus, capsaicin morphed the descriptor pattern of the blade to become more capsaicin-like, which is probably explained best by peripheral sensitization of the TRPV1 receptor. Quantitative sensory testing in capsaicin-sensitized skin revealed hyperalgesia to heat and pressure stimuli, and loss of cold and cold pain sensitivity. These findings support our hypothesis that the blade models the early tissue-strain-related mechanical pain phase of surgical incisions.

Capsaicin-Induced Skin Desensitization Differentially Affects A-Delta and C-Fiber-Mediated Heat Sensitivity.

Localized neuropathic pain can be relieved following the topical application of high-concentration capsaicin. This clinical effect is thought to be related to the temporary desensitization of capsaicin- and heat-sensitive epidermal nociceptors. The objective of the present study was to examine whether the changes in thermal sensitivity induced by high-concentration topical capsaicin can be explained entirely by desensitization of capsaicin-sensitive afferents. For this purpose, we characterized, in 20 healthy human volunteers, the time course and spatial extent of the changes in sensitivity to thermal stimuli preferentially activating heat-sensitive A-fiber nociceptors, heat-sensitive C-fiber afferents, and cool-sensitive A-fiber afferents. The volar forearm was treated with a high-concentration capsaicin patch for 1 h. Transient heat, warm and cold stimuli designed to activate Aδ- and C-fiber thermonociceptors, C-fiber warm receptors, and Aδ-fiber cold receptors were applied to the skin before and after treatment at days 1, 3, and 7. Reaction times, intensity ratings, and quality descriptors were collected. The stimuli were applied both within the capsaicin-treated skin and around the capsaicin-treated skin to map the changes in thermal sensitivity. We found that topical capsaicin selectively impairs heat sensitivity without any concomitant changes in cold sensitivity. Most interestingly, we observed a differential effect on the sensitivity to thermal inputs conveyed by Aδ- and C-fibers. Reduced sensitivity to Aδ-fiber-mediated heat was restricted to the capsaicin-treated skin, whereas reduced sensitivity to C-fiber-mediated heat extended well beyond the treated skin. Moreover, the time course of the reduced sensitivity to C-fiber-mediated input was more prolonged than the reduced sensitivity to Aδ-fiber-mediated input.

Repeat treatment with capsaicin 8% patch (179mg capsaicin cutaneous patch): Effects on pain, quality of life, and patient satisfaction in painful diabetic peripheral neuropathy: an open-label, randomized controlled clinical trial

Objective: To determine long-term safety and effectiveness of repeat treatments with a high concentration capsaicin patch. Methods: In this 52-week, open-label, randomized controlled study, patients with painful diabetic peripheral neuropathy (PDPN) received either capsaicin patch: (30- or 60-min; 1–7 treatments to the feet) plus SOC or SOC alone. Effectiveness was assessed, by changes from baseline to end of study (EoS), in average and severity of pain, pain interference with daily function (Brief Pain Inventory-Diabetic Neuropathy version), responder rates, Patient Global Impression of Change (PGIC), and EuroQol 5-dimension (EQ-5D) questionnaire. Results: 468 patients were randomized (n=156 and n=157, 30 and 60-min respectively; SOC alone, n=155). Safety data have been reported previously. Changes in average pain from baseline to EoS (mean percentage (SD)) were: 30-min, −37.5% (32.9); 60-min, −40.8% (39.7); SOC alone, −13.9% (74.6). The difference between groups increased progressively from −17.7% and −18.6% at Month 1 for 30- and 60-min., respectively, to −21.9% and −24% at Month 12. More 30% responders occurred in the capsaicin groups (30-min, 67.3%; 60-min, 67.5%) and more felt: very much or much improved” (30-min, 24.2%; 60-min, 24.5%), compared with SOC alone (40.6% and 9.5% respectively). A greater mean improvement in EQ-5D utility index and EQ-5D visual analog scale score, from baseline to Month 12, was observed with the 30-min (0.12) and 60-min (0.15) versus SOC alone (0.07) and mean (SD), 30–min (10.4 [18.5]) and 60-min (11.2 [21.4]) versus SOC alone (5.5 [18.1]) respectively. Conclusion: Capsaicin 8% patch showed differential effectiveness over SOC alone, further increasing with repeat treatments.

Functional and histological improvements of small nerve neuropathy after high-concentration capsaicin patch application: A case study

Introduction:Small fiber neuropathy has been found to occur in a large variety of pathological onditions, and the gold standard for diagnosis of small fiber neuropathy is skin biopsy. Sudorimetry is now considered an accurate technique to evaluate small fiber function with a good sensitivity and specificity for the diagnosis of small fiber neuropathy. Capsaicin high-concentration patch is approved for the treatment of peripheral neuropathic pain in adults either alone or in combination with other medicinal products for pain.Methods:We describe the case of a 50-year-old woman diagnosed with small fiber neuropathy. After 2 previous treatment failures, she was proposed a treatment with high-dose capsaicin patches on the sole of her foot. The patient experienced an important diminution of her neuropathic pain. There was a 50% decrease in the pain numeric scale. Electrochemical skin conductance and skin biopsy were repeated 3 months after patch application.Results:At 3 months, the patient then experienced an important diminution of her neuropathic pain, electrochemical skin conductance had normalized both in the hands and feet and intraepidermal nerve fiber density at distal leg increased almost reaching normal range.Conclusion:This case report shows the correlation between clinical improvement, electrochemical skin conductance normalization, and intraepidermal nerve fiber density improvement after a high-dose capsaicin patch in a patient with small fiber neuropathy.

(392) Postherpetic neuralgia treatment with high concentration capsaicin patch: Three Cases demonstrating reduction in pain receptive field without associated reduction in pain intensity

(392) Postherpetic neuralgia treatment with high concentration capsaicin patch: Three Cases demonstrating reduction in pain receptive field without associated reduction in pain intensity

Efficacy and Safety of 0.625% and 1.25% Capsaicin Patch in Peripheral Neuropathic Pain: Multi-Center, Randomized, and Semi-Double Blind Controlled Study

Background: Topical capsaicin therapy may be of benefit in providing pain relief in patients with peripheral neuropathy. Objectives: To investigate the efficacy and safety of 0.625% (50 µg/cm2 ) and 1.25% (100 µg/cm2 ) capsaicin patches (CPs) compared to conventional 0.075% capsaicin cream or placebo patches in patients suffering from peripheral neuropathy. Study Design: Early Phase II, multi-center, randomized, semi-double-blind, and placebocontrolled clinical trial. Setting: Two medical college teaching hospitals. Methods: Sixty patients were randomized to the 0.625% CP, 1.25% CP, placebo-controlled patch, or 0.075% capsaicin cream. The primary efficacy endpoint was the mean difference in the change of daily numerical rating scale (NRS) pain score. Secondary endpoints included values for the Daily Sleep Interference Scale, the percentage of patients achieving a ≥ 30% or ≥ 50% reduction in pain, and data for Global Impression Change (GIC) and EQ-5D. Results: Patients treated with the 0.625% CP and 0.075% capsaicin cream showed statistically significant improvements in pain after 6-weeks of test drug application. Daily sleep disorder scores were improved only for those patients applying the 0.075% capsaicin cream. For patient-derived GIC scores, the majority (11 of 12) of patients in the 0.625% CP group reported that their pain was improved. For the safety evaluation, 2 severe adverse events were reported for the 0.075% capsaicin cream group only. Repetitive patch application was related to minor skin problems such as a burning sensation, erythema, pruritus, and vesicles in 28 patients (46.67%). Limitations: The small sample size and relatively high dropout rates. Conclusion: Our data indicate that the 0.625% CP may prove to be an effective and safe alternative with which to treat patients with peripheral neuropathy and could replace the high concentration (8%) CP. Further studies are now needed to definitively establish efficacy. Key words: Capsaicin, patch, CP, topical capsaicin, neuropathic pain, peripheral neuropathic pain, PNP, high concentration CP

Use of High-Concentration Capsaicin Patch for the Treatment of Pelvic Pain: Observational Study of 60 Inpatients

Chronic pelvic, perineal and gluteal neuralgia is often experienced in a similar way to neuropathic pain, in the territories of four nerves: ilio-inguinal, pudendal, inferior cluneal and posterior gluteal nerves. These pains are often refractory to medical treatment based on the use of systemic molecules with disabling adverse effects and surgical procedure may be necessary. The objective of this study was to evaluate the efficacy and safety of treatment with a high-concentration capsaicin patch in these indications. This study was prospective, nonrandomized, and observational. Federative Center of Pelvi-Perineology in the University Hospital of Nantes, France. Sixty patients with pelvic neuralgia were treated with high-concentration capsaicin patch. The primary endpoint was Patient Global Impression of Change (PGIC) and secondary endpoints included pain intensity on a Numerical Rating Scale (NRS), maximum sitting duration at the end of the day, Medication Consumption Score (MQS), and patient global improvement (from -100% to + 100%). Twenty four percent of the 60 patients included in the study declared that they felt "very much improved" or "much improved" (PGIC = 1 or 2) and these patients reported an average 58% improvement and a 3.4-point reduction on the NRS. Among the "good responder" patients, patients with coccygodynia appear to obtain the bestresults, as 37% of these patients declared that they were much improved with an average 63% improvement No serious adverse effects were observed and treatment was well tolerated. This study is limited by its relatively small sample size and non-randomized study. These results suggest the value of high-concentration capsaicin 8% patch in the treatment strategy for patients with chronic pelvic, perineal and gluteal neuralgia. This treatment would be particularly indicated in the management of coccygodynia.Key words: Pelvic pain, neuropathic pain, pudendal nerve, ilio-inguinal nerve, inferior cluneal nerve, posterior gluteal nerve, capsaicin, capsaicin patch, coccygodynia.

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

Topical creams with capsaicin are used to treat pain from a wide range of chronic conditions including neuropathic pain. Following application to the skin capsaicin causes enhanced sensitivity to noxious stimuli, followed by a period with reduced sensitivity and, after repeated applications, persistent desensitisation. There is uncertainty about the efficacy and tolerability of capsaicin for treating painful chronic neuropathies. This is an update of an earlier review of topical capsaicin for chronic neuropathic pain in adults that looked at all doses and formulations of capsaicin. The original review has now been split: here we consider only formulations using a low concentration of capsaicin (< 1%) applied several times daily over several weeks, while another review will consider a single application of capsaicin at a high concentration.To review the evidence from controlled trials on the efficacy and tolerability of topically applied low-concentration (< 1%) capsaicin in chronic neuropathic pain in adults.Cochrane CENTRAL, MEDLINE, EMBASE and Oxford Pain Relief Database, searched to July 2012.Randomised, double-blind, placebo-controlled studies of at least six weeks' duration, using low-concentration (< 1%) topical capsaicin to treat neuropathic pain.Two review authors independently assessed study quality and validity, and extracted data. Information was extracted on numbers of participants with pain relief (clinical improvement) after at least six weeks, and with local skin reactions, and used to calculate relative risk (or risk ratio, RR) and numbers needed to treat to benefit (NNT) and harm (NNH). Details of definition of pain relief and specific adverse events were sought.No additional studies were identified for this update of low concentration capsaicin. Included studies were published before 1996. Six studies (389 participants in total) compared regular application of low dose (0.075%) capsaicin cream with placebo cream. There was substantial heterogeneity in results, probably as a result of the small number of studies each with small numbers of participants, as well as the different pain conditions studied and different definitions of "clinical success" reported. 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% confidence interval (CI) 2.1 to 3.1). All studies satisfied minimum criteria for quality and validity, but maintenance of blinding remains a potential problem.There were insufficient data to draw any conclusions about the efficacy of low-concentration capsaicin cream in the treatment of neuropathic pain. The information we have suggests that low-concentration topical capsaicin is without meaningful effect beyond that found in placebo creams; given the potential for bias from small study size, this makes it unlikely that low-concentration topical capsaicin has any meaningful use in clinical practice. Local skin irritation, which was often mild and transient but may lead to withdrawal, was common. Systemic adverse effects were rare.

Treatment of postherpetic neuralgia

At present, there is no special therapy for postherpetic neuralgia (PHN), but the symptoms of PHN can be alleviated to the maximum extent by appropriate comprehensive therapy. Anticonvulsants are still commonly used drugs, including gabapentin, pregabalin and tricyclic antidepressants. Topical treatment is a recommended therapeutic approach to PHN in clinic. High-concentration capsaicin patches can be applied in patients who fail to respond to other treatments or cannot tolerate systemic therapies. Neither narcotic analgesics nor nerve block therapy is recommended as the first-line therapy because of their adverse effects. In addition, the application of new drugs such as tumor necrosis factor-α inhibitors and patient-controlled analgesia in patients with PHN have gained increasing attention. Key words: Neuralgia, postherpetic; Therapeutic uses; Pharmaceutical preparations; External application drugs; Physical therapy modalities; Psychotherapeutic processes

Neuropathic pain: New analysis sheds light on optimal drug therapy

Finer points Finnerup and colleagues conducted a systematic review and meta-analysis of 229 reports or trials (both published and unpublished) that assessed the use of systemic and topical therapies for the treatment of neuropathic pain. They applied their results to update current practice recommendations released by the Special Interest Group on Neuropathic Pain (NeuPSIG). The investigators noted that most trial outcomes were modest and publication bias may account for a 10% overstatement of treatment effects. On the basis of GRADE recommendations, the analysis showed that there is strong evidence to support the use of tricyclic antidepressants, serotonin–noradrenaline reuptake inhibitors (particularly duloxetine), pregabalin, and gabapentin as rst-line agents for patients with neuropathic pain. Capsaicin 8% patches, lidocaine patches, tramadol, subcutaneous botulinum toxin A, and strong opioids all had weak GRADE recommendations for use based on poorer evidence, high costs, or safety concerns. Both high-concentration capsaicin and lidocaine patches were recommended as second-line agents for peripheral neuropathic pain, and botulinum toxin A as a third-line agent when used by a specialist to manage this condition.

Assessment of the feasibility of high-concentration capsaicin patches in the pain unit of a tertiary hospital for a population of mixed refractory peripheral neuropathic pain syndromes in non-diabetic patients.

BackgroundHigh-concentration-capsaicin-patches (Qutenza®) have been put on the market as a treatment for peripheral neuropathic pain. A minimum infrastructure and a determinate skill set for its application are required. Our aim was to assess the feasibility of treatment with high-concentration-capsaicin-patches in clinical practice in a variety of refractory peripheral neuropathic pain syndromes in non-diabetic patients.MethodsObservational, prospective, single-center study of patients attended to in the Pain Unit of a tertiary hospital, ≥18 year-old non-responders to multimodal analgesia of both genders. The feasibility for the application of capsaicin patch in clinical practice was evaluated by means of the number of patients controlled per day when this one was applied and by means of the times used for patch application.ResultsBetween October 2010 and September 2011, 20 consecutive non-diabetic patients (7 males, 13 females) with different diagnoses of refractory peripheral neuropathic pain syndromes, with a median (range) age of 60 (33–88) years-old were treated with a single patch application. The median (range) number of patients monitored per day was not modified when the capsaicin patch was applied [27 (26–29)] in comparison with it was not applied [28 (26–30)]. The median (range) total time to determine and mark the painful area was 9 (6–15) minutes and of patch application was 60 (58–65) minutes. No important adverse reactions were observed.ConclusionHigh-concentration-capsaicin-patch treatment was feasible in our unit for the treatment of a population with refractory peripheral neuropathic pain. The routine of our unit was not affected by its use.