Effectiveness and safety of topical capsaicin cream in the treatment of chronic soft tissue pain

The influence of pain and kinesiophobia on motor control of the upper limb: how pointing task paradigms can point to new avenues of understanding

ABSTRACT

People experiencing kinesiophobia are more likely to develop persistent disabilities and chronic pain. However, the impact of kinesiophobia on the motor system remains poorly understood. We investigated whether kinesiophobia could modulate shoulder pain-induced changes in (1) kinematic parameters and muscle activation during functional movement and (2) corticospinal excitability. Thirty healthy, pain-free subjects took part in the study. Shoulder, elbow, and finger kinematics, as well as electromyographic activity of the upper trapezius and anterior deltoid muscles, were recorded while subjects performed a pointing task before and during pain induced by capsaicin at the shoulder. Anterior deltoid cortical changes in excitability were assessed through the slope of transcranial magnetic stimulation input-output curves obtained before and during pain. Results revealed that pain reduced shoulder electromyographic activity and had a variable effect on finger kinematics, with individuals with higher kinesiophobia showing greater reduction in finger target traveled distance. Kinesiophobia scores were also correlated with the changes in deltoid corticospinal excitability, suggesting that the latter can influence motor activity as soon as the motor signal emerges. Taken together, these results suggest that pain and kinesiophobia interact with motor control adaptation.

Factors explaining individual differences in the oral perception of capsaicin, l-menthol, and aluminum ammonium sulfate

This research focused on the oral perception of naturally occurring chemical food compounds that are used in the pharma and food industries due to their pharmacological properties. They stimulate chemically sensitive receptors of the somatosensory system and are also chemesthetic compounds. Capsaicin is a naturally occurring alkaloid activating pungency perception. l-Menthol is a cyclic monoterpene working also as a medical cooling agent. Aluminum ammonium sulfate is used as a dehydrating agent and additive known to activate astringency in oral cavity. The objective of the study was to identify factors explaining individual differences in the perception of oral chemesthesis measured as sensitivity to chemesthetic compounds and their recognition. The subjects (N = 205) evaluated quality-specific prototypic compounds at five different concentration levels. Differences between gender were discovered in capsaicin sensitivity with men being less sensitive than women. Age was associated with the perception of capsaicin, l-menthol, aluminum ammonium sulfate, and the combined oral chemesthetic sensitivity. Quality-specific recognition ratings were also contributing to the sensitivity to chemesthetic compounds. A combined oral chemesthetic recognition score was created based on quality-specific recognition ratings. Increasing age generally indicated weaker recognition skills. Better recognizers had a higher combined oral chemesthetic sensitivity score than poorer recognizers. These results provide new information about chemesthesis. The results suggest that age and gender are important factors in explaining individual differences in sensitivity to capsaicin, l-menthol, and aluminum ammonium sulfate. In addition, recognition skills are associated with the sensitivity based on the quality-specific recognition scores.

Development of Capsaicin-Containing Analgesic Silicone-Based Transdermal Patches

Transdermal therapeutic systems (TTSs) enable convenient dosing in drug therapy. Modified silicone-polymer-based patches are well-controlled and cost-effective matrix diffusion systems. In the present study, we investigated the substance release properties, skin penetration, and analgesic effect of this type of TTS loaded with low-dose capsaicin. Release properties were measured in Franz diffusion cell and continuous flow-through cell approaches. Capsaicin was detected with HPLC-UV and UV spectrophotometry. Raman spectroscopy was conducted on human skin samples exposed to the TTS. A surgical incision or carrageenan injection was performed on one hind paw of male Wistar rats. TTSs were applied to the epilated dorsal skin. Patches were kept on the animals for 6 h. The thermal hyperalgesia and mechanical pain threshold of the hind paws were detected. Patches exhibited controlled, zero-order kinetic capsaicin release. According to the Raman mapping, capsaicin penetrated into the epidermis and dermis of human skin, where the target receptors are expressed. The thermal pain threshold drop of the operated rat paws was reversed by capsaicin treatment compared to that of animals treated with control patches. It was concluded that our modified silicone-polymer-based capsaicin-containing TTS is suitable for the relief of traumatic and inflammatory pain.

Bioactive Compounds for Fibromyalgia-like Symptoms: A Narrative Review and Future Perspectives

Fibromyalgia (FM) is a prevalent, chronic condition without a cure or reliable therapy. The etiopathogenesis of this syndrome is ambiguous, which has heightened the challenge of discovering treatments to minimize patients’ painful symptoms. FM is characterized by diffuse musculoskeletal pain usually accompanied by functional pain syndromes, such as fatigue, sleep disturbances, cognitive difficulties, and mood issues. Currently available treatment options for FM are limited. Recent studies have suggested a potential role for dietary bioactive compounds in FM management. We performed a narrative review to evaluate the existing evidence regarding the dietary bioactive compounds for FM, and we proposed molecular mechanisms on this topic. The inclusion criteria were (i) human, in vivo, or in vitro studies, (ii) studies related to the effect of bioactive compounds on FM-like symptoms, (iii) peer-reviewed literature, and (iv) publications until February 2022 in PubMed and Google Scholar. Exclusion criteria were (i) study designs using CCI, SNI, or SNL models because they are more NP models rather than FM models, and (ii) studies published in a language other than English. Keywords were dietary bioactive compounds, fibromyalgia, cell, animals, humans. Here, we report the effects of commonly consumed bioactive compounds (capsaicin, ginger, curcumin, n-3 PUFA, grape seed extract, naringin, and genistein) on FM-like symptoms in cellular, animal, and human studies. Cellular studies demonstrated that these bioactive compounds reduce pro-inflammatory production and increase antioxidant capacity of neurons or myoblasts that regulate apoptosis/cell survival. Animal studies showed that these regularly consumed bioactive compounds have an effect on FM-like symptoms, as evidenced by decreased pain hypersensitivity and fatigue as well as improved social behaviors. Further studies are warranted to allow meaningful comparison and quantification of the efficacy of these bioactive compounds on FM-like symptoms across studies, in terms of actual changes in antioxidant capacity, pain hypersensitivity, fatigue, and social behaviors. To date, human studies regarding the efficacy of these bioactive compounds on FM-like symptoms are limited and inconclusive. Our review identifies this important knowledge gap and proposes that the development and use of improved preclinical FM models are needed, particularly concerning the usage of female animals to better mimic FM pathophysiology and symptomatology.

[Real-world clinical efficacy assessment of Kapsikam a combined topical medication based on nonivamide synthetic capsaicin analog in patients with acute nonspecific musculoskeletal back pain: LOCUS observational study outcomes]

OBJECTIVE

Evaluation of the effect of local therapy with Kapsikam on the dynamics of clinical symptoms and indices of the disability scale, as well as on reducing the doses of systemic non-steroidal anti-inflammatory drugs (NSAIDs) used in patients with acute back pain (LOCUS study).

MATERIALS AND METHODS

An observational study included 120 patients with nonspecific pain in the lower back and a verified diagnosis of Lumbodynia M54.5; «Lumbodynia with sciatica» M54.4, of which 78 received in addition to the basic treatment with systemic NSAIDs topical drug Kapsikam and 42 - only basic treatment.

Results and conclusion. The addition of Kapsikam ointment to systemic NSAIDs accelerated the onset of the analgesic effect, which made it possible to discontinue NSAIDs in 50% of patients after 5 days of use. Local therapy was accompanied by easily tolerated adverse events that did not affect the use of the drug. 97.4% of patients used the study drug as prescribed until the end of the study.

A Comprehensive Review of Over the Counter Treatment for Chronic Low Back Pain

PURPOSE OF THE REVIEW

Chronic low back pain (CLBP) is a major contributor to societal disease burden and years lived with disability. Nonspecific low back pain (LBP) is attributed to physical and psychosocial factors, including lifestyle factors, obesity, and depression. Mechanical low back pain occurs related to repeated trauma to or overuse of the spine, intervertebral disks, and surrounding tissues. This causes disc herniation, vertebral compression fractures, lumbar spondylosis, spondylolisthesis, and lumbosacral muscle strain.

RECENT FINDINGS

A systematic review of relevant literature was conducted. CENTRAL, MEDLINE, EMBASE, PubMed, and two clinical trials registry databases up to 24 June 2015 were included in this review. Search terms included: low back pain, over the counter, non-steroidal anti-inflammatory (NSAID), CLBP, ibuprofen, naproxen, acetaminophen, disk herniation, lumbar spondylosis, vertebral compression fractures, spondylolisthesis, and lumbosacral muscle strain. Over-the-counter analgesics are the most frequently used first-line medication for LBP, and current guidelines indicate that over-the-counter medications should be the first prescribed treatment for non-specific LBP. Current literature suggests that NSAIDs and acetaminophen as well as antidepressants, muscle relaxants, and opioids are effective treatments for CLBP. Recent randomized controlled trials also evaluate the benefit of buprenorphine, tramadol, and strong opioids such as oxycodone. This systematic review discusses current evidence pertaining to non-prescription treatment options for chronic low back pain.

Comparative safety review of current treatment options for chronic low back pain and unmet needs: a narrative review

Introduction: The healthcare expenditures in the United States are substantial for the management of refractory, chronic low back pain (CLBP). The objective of this review is to summarize and evaluate the safety profiles of different pharmacological treatment options used in the management of CLBP.Areas covered: The authors conducted a search of randomized controlled trials (RCTs) assessing the safety profiles of different pharmacological agents used in the management of CLBP. This narrative review covered corticosteroids, opioids, antidepressants, gabapentinoids, nonsteroidal anti-inflammatory drugs, muscle relaxants, anti-nerve growth factor antibodies and topical agents, as monotherapy or in combination.Expert opinion: The risk-benefit ratio of a particular treatment is a subject driving the ongoing development of pharmaceuticals. The most commonly reported AEs across all drug classes are of gastrointestinal nature, followed by neurological and skin-related. These AEs include nausea, dizziness, constipation, arthralgia, headache, dry mouth, pruritus, etc. The majority of the AEs reported are not life-threatening, although they may lower patients' quality of life, thus, affecting their compliance. One of the biggest limitations of our review stems from the paucity of safety assessments in published RCTs. Advances in our understanding of the neurobiology of pain will promote development of new therapeutic strategies.

Herbal Medicine for Pain Management: Efficacy and Drug Interactions

Complementary and alternative medicines such as herbal medicines are not currently part of the conventional medical system. As the popularity of and global market for herbal medicine grows among all age groups, with supporting scientific data and clinical trials, specific alternative treatments such as herbal medicine can be reclassified as a practice of conventional medicine. One of the most common conditions for which adults use herbal medicine is pain. However, herbal medicines carry safety concerns and may impact the efficacy of conventional therapies. Unfortunately, mechanisms of action are poorly understood, and their use is unregulated and often underreported to medical professionals. This review aims to compile common and available herbal medicines which can be used as an alternative to or in combination with conventional pain management approaches. Efficacy and safety are assessed through clinical studies on pain relief. Ensuing herb–drug interactions such as cytochrome modulation, additive and synergistic effects, and contraindications are discussed. While self-management has been recognized as part of the overall treatment strategy for patients suffering from chronic pain, it is important for practitioners to be able to also optimize and integrate herbal medicine and, if warranted, other complementary and alternative medicines into their care.

Bayesian-based withdrawal estimates using pharmacokinetic parameters for two capsaicinoid-containing products administered to horses

Capsaicinoids deter horses from chewing on bandages and are applied topically to provide analgesia to musculoskeletal injuries. They are banned during competition due to their nerve blocking properties. The pharmacokinetics of oral (PO) and direct gastric administration via nasogastric tube (NG), or topical (TOP) administration of two capsaicinoid-containing products were investigated, and the withdrawal times required prior to competition were estimated. Capsaicin (CAP) and dihydrocapsaicin (DCAP) were quantified in plasma, and both compounds were best described by a delayed absorption two compartment elimination model following PO administration and by a first order absorption one compartment elimination model following TOP administration. Capsaicin and DCAP could not be quantified in most samples following NG administration. Following PO administration, the time to maximum plasma concentration (T_max ) for CAP and DCAP was 0.25 (0.08-0.50) hr. Following TOP application, the Tmax for CAP and DCAP was 4 (2-6) and 5 (3-12) hr, respectively. By 8 hr post-PO administration and 36 hr post-TOP application, CAP and DCAP were below the lower limit of quantification. Capsaicin and DCAP were not detected in urine samples. Withdrawal times were predicted using the 99.99% credibility interval limits of the pharmacokinetic parameters calculated with Bayesian estimation.

Topical capsaicin versus topical ibuprofen in acute musculoskeletal injuries: A randomized, double-blind trial

Background:

Acute musculoskeletal pain is one of the common causes of emergency admissions. Topical analgesics are an easily tolerated option in the treatment of these pains.

Objective:

This study aimed to compare the efficacy of topical capsaicin and topical non-steroidal anti-inflammatory drugs in acute musculoskeletal injuries.

Methods:

In this prospective, randomized, controlled, double-blinded study, patients were allocated to two groups—the topical non-steroidal anti-inflammatory drug (n = 60) and topical capsaicin (n = 59). For both groups, the first dose treatment was applied as a thin layer in the emergency department to a maximum area of 5 × 5 cm. The remaining doses were administered at home by the patients for 72 h. The initial visual analog scale scores were compared with the 60th and 120th minute as well as the 24th and 72nd hour values. Differences between the visual analog scale scores, clinical response to the treatment, and side effects were evaluated.

Results:

The proportional reduction in visual analog scale scores for topical capsaicin was significantly higher, especially at 36 and 72 h. These rates were 0.75 (95% confidence interval: 0.77–1.42; p = 0.029) and 9.08 (95% confidence interval: 1.02–17.14; p = 0.028) at 36 h, respectively. At 72 h, they were 1.27 (95% confidence interval: 0.48–2.05; p = 0.002) and 17.07 (95% confidence interval: 8.39–25.76; p < 0.001), respectively. In the topical capsaicin group, the clinical response to treatment was significantly higher (p = 0.001). Treatment-related systemic side effects were experienced only in the topical non-steroidal anti-inflammatory drug group (1.7%).

Conclusion:

Topical capsaicin can be used safely in patients presenting to the emergency department with acute pain with its high analgesic efficacy and absence of systemic side effects.

Efficacy of topical interventions for temporomandibular disorders compared to placebo or control therapy: a systematic review with meta-analysis

This systematic review focused on the efficacy of topical products in reducing temporomandibular joint disorder (TMD)-associated pain, in comparison to placebo or control interventions. The EMBASE, Web of Science, Cochrane Library, and MEDLINE via PubMed databases were searched for randomized controlled trials (RCTs) using topical interventions in adults diagnosed with TMD. The pain intensity was the primary outcome, and other clinical findings were the secondary outcomes. The risk of bias was evaluated according to the Cochrane's handbook. The search up to February 7, 2020 identified a total of 496 unduplicated references. Nine RCTs with 355 adult patients diagnosed with TMD were included. The meta-analysis did not show a significant reduction in baseline pain intensity in the nonsteroidal anti-inflammatory drug (NSAIDs) group, when compared to the placebo group (P = 0.288). One study demonstrated a statistically significant pain score decrease for Theraflex-TMJ compared to placebo after 10 d of treatment (P = 0.003) and follow-up, 5 d after the last application (P = 0.027). Ping On reduced pain at 4 weeks of application (P < 0.001) but not after 7 d of application (P = 0.136). In one study, cannabidiol (CBD) significantly improved the pain intensity compared to placebo (P < 0.001). However, no differences were found with capsaicin in the two studies (P = 0.465). Evidence was of low quality because the studies were considered as having an unclear or a high risk of bias and a small number of studies were analyzed. The evidence is not sufficient to support the use of topical NSAIDs and capsaicin, and limited evidence was found for Threraflex-TMJ, bee venom, Ping On, and CBD, with only one study reporting for each. Additional studies are recommended to validate these results.

Comparison of topical capsaicin and topical piroxicam in the treatment of acute trauma-induced pain: A randomized double-blind trial

BACKGROUND

This study aimed to compare the analgesic efficacy of topical capsaicin and topical piroxicam in acute musculoskeletal injuries.

METHODS

This is a prospective, randomized, controlled, double-blinded study. The data for the 67 patients in the piroxicam group and the 69 in the capsaicin group were examined. The initial visual analog scale (VAS) scores were compared with the 60th and 120th minute as well as the 24th and 72nd hour values. Differences between the VAS scores, clinical effectiveness of the treatment and side effects were evaluated.

RESULTS

In the capsaicin group, the mean difference in the delta VAS scores was significantly higher at each measurement time. The mean of the percentage of reduction in the VAS scores of the topical capsaicin group was significantly higher than that in the topical piroxicam group. The highest difference in terms of both outcomes was determined at the 72nd hour VAS change. Mean differences were 1.53 (95% CI: 0.85-2.221) and 19.7 (95% CI: 12.4-27.2) respectively (p < 0.001). In the capsaicin group, the clinical effect of the treatment was found significantly higher (p < 0.01). The difference between the clinical effectiveness of the groups regarding the treatment outcomes was also statistically significant (p < 0.001). There was no significant difference between the patient groups regarding the presence of side effects.

CONCLUSION

Topical capsaicin can be used as an alternative to topical piroxicam initially and at follow-up in patients presenting to the emergency department with acute pain as there were no observable differences in side-effects between the two groups.

Conditional Recommendations for Specific Dietary Ingredients as an Approach to Chronic Musculoskeletal Pain: Evidence-Based Decision Aid for Health Care Providers, Participants, and Policy Makers

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular for a wide range of pain conditions, decisions to use supplements are often driven by information that is not evidence-based. This work evaluates whether the current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. A decision table was constructed to make evidence-informed judgments across factors required for decision-making, and recommendations were made for practice and self-care use.

RESULTS

Nineteen dietary ingredients were included. Conditional evidence-based recommendations were made for the use of avocado soybean unsaponifiables, capsaicin, curcuma, ginger, glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D. In these cases, desirable effects outweighed undesirable effects, but there was uncertainty about the trade-offs, either because the evidence was low quality or because benefits and downsides were closely balanced.

CONCLUSIONS

The evidence showed that certain dietary ingredients, when taken as part of a balanced diet and/or as a supplement (e.g., pill, tablet, capsule, cream), may alleviate musculoskeletal pain with no to minimal risk of harm. This finding emphasizes and reinforces the critical importance of shared decision-making between Operators and their health care providers.

Efficacy and Safety of Diclofenac + Capsaicin Gel in Patients with Acute Back/Neck Pain: A Multicenter Randomized Controlled Study

Introduction

Back and neck pain are common musculoskeletal disorders. Topical non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used to reduce pain and inflammation with fewer systemic side effects and drug interactions compared with oral NSAIDs. This study assessed efficacy and tolerability of a topical combination of capsaicin + diclofenac to treat acute back/neck pain.

Methods

In a randomized, double-blind, controlled, multicenter, parallel group trial, 746 patients were treated twice-daily for 5 days with diclofenac 2% + capsaicin 0.075%, diclofenac 2%, capsaicin 0.075% or placebo. Efficacy assessments included change and area under the curve in pain on movement for the worst procedure (POM_WP), change in pressure algometry, and number of patients with decrease in POM_WP of ≥ 30% and ≥ 50%. Adverse events (AEs) were recorded.

Results

Change in POM_WP between baseline and day 2 evening, 1 h after drug application, demonstrates superiority of the combination (− 3.05 cm) versus diclofenac alone (− 2.33 cm) and placebo (− 2.45 cm), but not capsaicin alone (− 3.26 cm). AEs were consistent with known safety profiles.

Conclusion

Capsaicin alone and capsaicin + diclofenac showed superior benefit compared with placebo. However, diclofenac alone demonstrated efficacy comparable with placebo, and therefore its addition to capsaicin added no increased pain relief over capsaicin alone.

Trial registration

ClinicalTrials.gov identifier; NCT02700815.

Electronic supplementary material

The online version of this article (10.1007/s40122-020-00161-9) contains supplementary material, which is available to authorized users.

Fenugreek dermal patch, a new natural topical antinociceptive medication for relieving the postherniotomy pain, a double-blind placebo controlled trial

Background

Fenugreek seeds have shown antinociceptive effect in animal studies. This double-blind placebo controlled trial was designed to study the effect of fenugreek transdermal patch 10% (FDP) for management of inguinal hernia (IH) post-operative pain.

Methods

Standardized extract of fenugreek seeds was used for FDP formulation. Ninety patients treated with 10% FDP, diclofenac dermal patch 1% (DP) and placebo twice daily after IH surgery. The pain intensity score was evaluated using a visual analogue score (VAS) up to 48 h after operation. Morphine consumption and diclofenac suppository demand were evaluated too.

Results

The pain score was significantly reduced in FDP group in comparison with the placebo group. This effect was also significantly different from DP up to 6 h after surgery (p<0.05). Morphine consumption and diclofenc suppository demand were significantly decreased in FDP group (p<0.05).

Conclusion

In all, results of the present study indicated that FDP decreases pain score and demand for morphine in post-surgery patients in comparison to diclofenac patch, and this preparation could be a suit option as a natural antinociceptive agent for pain management.

Health-promoting properties of compounds derived from Capsicum sp. A review

This article presents multidirectional effects of capsaicin and its natural derivatives as well as natural and synthetic analogs in term of their therapeutic properties. Active agents present in various Capsicum genus plants exert analgesic, anti-inflammatory, antibacterial, antioxidant and gastroprotective effects. Furthermore, capsaicin positively influences the metabolism of lipids. Numerous research show that capsaicinoids inhibit proliferation and migration process of cancer cells, what makes them molecules of high interest in oncology. Among broad range of positive activities, we have focused only on those properties that have already found application in medicine or seemed to be the most probably used in the near future. Even if in low or single doses this compound has been reported successful in numerous therapies, the negative consequences of high doses or prolonged administration is also discussed in the review.

Representative literature on the phytonutrients category: Phenolic acids

Research concerning the benefits derived from dietary polyphenols, a significant class within the family of phytonutrients, has increased considerably in the last decade. Prior to the late 1990s, the nutritional spotlight focused on the antioxidant capabilities of carotenoids, vitamins, and minerals. More recently, however, research has emerged in strong support of the antioxidant capacity of polyphenols and their role in the prevention and/or treatment of certain cancers, diabetes, cardiovascular diseases, and inflammation. Polyphenols are categorized according to the nature of their carbon skeleton, ranging from basic phenolic molecules to highly complex compounds, such as flavonoids, the most common and widely studied of all phenolic compounds. The most prevalent phenolic acids include ellagic acid, gallic acid, tannic acid, and capsaicin.

Nicoboxil/nonivamide cream effectively and safely reduces acute nonspecific low back pain - a randomized, placebo-controlled trial

Background/objective

Low back pain affects many patients and has a high socioeconomic impact. Topical capsaicinoids have been used for decades to treat musculoskeletal pain. This study investigated the effects of the fixed dose combination (FDC) of nonivamide (a capsaicinoid) and nicoboxil (a nicotinic acid ester) cream in the treatment of acute nonspecific low back pain.

Materials and methods

This phase III randomized, double-blind, placebo-controlled, multinational, multi-center trial investigated efficacy, safety, and tolerability of topical nicoboxil 1.08%/nonivamide 0.17% (Finalgon^® cream) in treatment of acute nonspecific low back pain with the endpoints: pain intensity (PI) difference between pre-dose baseline and 8 hours after first application and the end of treatment, mobility score, and efficacy score.

Results

Patients (n=138), 21–65 years of age, were treated for up to 4 days with FDC or placebo cream. Mean baseline PI was 6.8 on a 0–10 point numerical rating scale. After 8 hours, pain was more reduced with the FDC than with placebo (adjusted means: 2.824 vs. 0.975 points; p<0.0001). On the last treatment day, mean pain reduction by the FDC was stronger than with placebo (adjusted means: 5.132 vs. 2.174 points; p<0.0001). Mobility on Day 1 was in favor of the FDC when compared to placebo (odds ratio [95% confidence interval {CI}]: 7.200 [3.609, 14.363], p<0.0001). At the end of treatment, patients treated with the FDC rated efficacy significantly higher than placebo (odds ratio [95% CI]: 11.370 [5.342, 24.199], p<0.0001). Both treatments were tolerated well. No serious adverse events were reported.

Conclusion

Nicoboxil/nonivamide cream is an effective and safe treatment for acute nonspecific low back pain, adding a promising treatment option.

Herbal Medicine for Low Back Pain: A Cochrane Review

STUDY DESIGN

Systematic review of randomized controlled trials (RCTs).

OBJECTIVES

To determine the effectiveness of herbal medicine for nonspecific low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Many people with chronic LBP use complementary and alternative medicine (CAM), visit CAM practitioners, or both. Several herbal medicines have been purported for use in treating people with LBP. This is an update of a Cochrane Review first published in 2006.

METHODS

We searched numerous electronic databases up to September 2014; checked reference lists in review articles, guidelines and retrieved trials; and personally contacted individuals with expertise in this area. We included RCTs examining adults (over 18 years of age) suffering from acute, sub-acute, or chronic nonspecific LBP. The interventions were herbal medicines that we defined as plants used for medicinal purposes in any form. Primary outcome measures were pain and function. Two review authors assessed risk of bias, GRADE criteria (GRADE 2004), and CONSORT compliance and a random subset were compared with assessments by a third individual. Two review authors assessed clinical relevance and resolved any disagreements by consensus.

RESULTS

Fourteen RCTs (2050 participants) were included. Capsicum frutescens (cayenne) reduces pain more than placebo. Although Harpagophytum procumbens (devil's claw), Salix alba (white willow bark), Symphytum officinale L. (comfrey), Solidago chilensis (Brazilian arnica), and lavender essential oil also seem to reduce pain more than placebo, evidence for these substances was of moderate quality at best. No significant adverse events were noted within the included trials.

CONCLUSIONS

Additional well-designed large trials are needed to test these herbal medicines against standard treatments. In general, the completeness of reporting in these trials was poor. Trialists should refer to the CONSORT statement extension for reporting trials of herbal medicine interventions.

LEVEL OF EVIDENCE

N/A.

Alternative methods of pain management for the older adult population: Review of topical pain medications

The older adult population is one of the fastest growing age groups in the United States. As this population continues to expand, determining the safest way to provide pain management has become increasingly important. More than 50% of community-dwelling older adults experience pain on a daily basis, and up to 83% of those in assisted living facilities experience persistent pain. Pain is exceedingly challenging to treat safely and effectively in the elderly because of the physiologic changes that occur as people age. In addition, many nonnarcotic medications with analgesic properties are listed in both the 2012 American Geriatrics Society Beers Criteria for Potentially Inappropriate Medication Use in Older Adults and the Pharmacy Quality Alliance high-risk medications lists. An approach to the growing challenge of managing pain in the elderly that is gaining popularity among community-dwelling patients is the use of topical pain medications. The goal of this article is to review some of the available literature regarding the use of various topical analgesics alone or in combination, and to discuss their known or theoretical mechanisms of peripheral pain modulation. Commercially available or compounded topical pain medications may be used to replace or augment doses of oral medications in an effort to decrease the risk of adverse drug events for older adult patients. When prescribing topical pain medications physicians should consider the nature of the pain targeted, the type of analgesia expected from each ingredient, the potential for systemic absorption, and related side effects.

Herbal medicine for low-back pain

BACKGROUND

Low-back pain (LBP) is a common condition and imposes a substantial economic burden upon people living in industrialized societies. A large proportion of people with chronic LBP use complementary and alternative medicine (CAM), visit CAM practitioners, or both. Several herbal medicines have been purported for use in treating people with LBP. This is an update of a Cochrane Review first published in 2006.

OBJECTIVES

To determine the effectiveness of herbal medicine for non-specific LBP.

SEARCH METHODS

We searched the following electronic databases up to September 2014: MEDLINE, EMBASE, CENTRAL, CINAHL, Clinical Trials.gov, World Health Organization International Clinical Trials Registry Portal and PubMed; checked reference lists in review articles, guidelines and retrieved trials; and personally contacted individuals with expertise in this area.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) examining adults (over 18 years of age) suffering from acute, sub-acute, or chronic non-specific LBP. The interventions were herbal medicines which we defined as plants used for medicinal purposes in any form. Primary outcome measures were pain and function.

DATA COLLECTION AND ANALYSIS

A library scientist with the Cochrane Back Review Group conducted the database searches. One review author contacted content experts and acquired relevant citations. We downloaded full references and abstracts of the identified studies and retrieved a hard copy of each study for final inclusion decisions. Two review authors assessed risk of bias, GRADE criteria (GRADE 2004), and CONSORT compliance and a random subset were compared to assessments by a third individual. Two review authors assessed clinical relevance and resolved any disagreements by consensus.

MAIN RESULTS

We included 14 RCTs (2050 participants) in this review. One trial on Solidago chilensis M. (Brazilian arnica) (20 participants) found very low quality evidence of reduction in perception of pain and improved flexibility with application of Brazilian arnica-containing gel twice daily as compared to placebo gel. Capsicum frutescens cream or plaster probably produces more favourable results than placebo in people with chronic LBP (three trials, 755 participants, moderate quality evidence). Based on current evidence, it is not clear whether topical capsicum cream is more beneficial for treating people with acute LBP compared to placebo (one trial, 40 participants, low quality evidence). Another trial found equivalence of C. frutescens cream to a homeopathic ointment (one trial, 161 participants, very low quality evidence). Daily doses of Harpagophytum procumbens (devil's claw), standardized to 50 mg or 100 mg harpagoside, may be better than placebo for short-term improvements in pain and may reduce use of rescue medication (two trials, 315 participants, low quality evidence). Another H. procumbens trial demonstrated relative equivalence to 12.5 mg per day of rofecoxib (Vioxx®) but was of very low quality (one trial, 88 participants, very low quality). Daily doses of Salix alba (white willow bark), standardized to 120 mg or 240 mg salicin, are probably better than placebo for short-term improvements in pain and rescue medication (two trials, 261 participants, moderate quality evidence). An additional trial demonstrated relative equivalence to 12.5 mg per day of rofecoxib (one trial, 228 participants) but was graded as very low quality evidence. S. alba minimally affected platelet thrombosis versus a cardioprotective dose of acetylsalicylate (one trial, 51 participants). One trial (120 participants) examining Symphytum officinale L. (comfrey root extract) found low quality evidence that a Kytta-Salbe comfrey extract ointment is better than placebo ointment for short-term improvements in pain as assessed by VAS. Aromatic lavender essential oil applied by acupressure may reduce subjective pain intensity and improve lateral spine flexion and walking time compared to untreated participants (one trial, 61 participants,very low quality evidence). No significant adverse events were noted within the included trials.

AUTHORS' CONCLUSIONS

C. frutescens (Cayenne) reduces pain more than placebo. Although H. procumbens, S. alba, S. officinale L., S. chilensis, and lavender essential oil also seem to reduce pain more than placebo, evidence for these substances was of moderate quality at best. Additional well-designed large trials are needed to test these herbal medicines against standard treatments. In general, the completeness of reporting in these trials was poor. Trialists should refer to the CONSORT statement extension for reporting trials of herbal medicine interventions.

Analgesic topical capsaicinoid therapy increases somatostatin-like immunoreactivity in the human plasma

The aim of the present study was to evaluate the therapeutic potential of local capsaicinoid (EMSPOMA(®) cream) treatment on chronic low back pain in patients with degenerative spine diseases and to investigate the possible mechanism of action of the therapy. The qualitative and quantitative analyses of capsaicinoids in EMSPOMA(®) cream were performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the clinical study 20 patients with degenerative spine diseases were involved in a self-controlled examination. During the 21 day therapy they received 30 min daily treatment with capsaicinoid (EMSPOMA(®)) cream to the lumbar region of the back. The pain (VASs, Oswestry Disability Index) and the mobility of the lumbar region of the spine (Schober's, Domján's L and R test) were detected at baseline and at the end of the 1st, 2nd and 3rd weeks. The plasma level of somatostatin-like immunoreactivity (SST-LI) was measured by radioimmunoassay (RIA) before and after the treatment on the first and the last day of the therapy. Nonivamide (0.01%) was identified as the only capsaicinoid molecule in the cream. In the clinical study the 21 day local nonivamide treatment reduced the pain sensation. Oswestry Disability Index decreased from 39 ± 3.9% to 32.5 ± 4.4%. VASs showed 37.29%-59.51% improvement. In the plasma level of SST-LI threefold elevation was observed after the first nonivamide treatment. We conclude that nonivamide treatment exerts analgesic action in chronic low back pain and causes the release of the antinociceptive and anti-inflammatory neuropeptide somatostatin which may play pivotal role in the pain-relieving effect.

Comparison of the effects of pelargonic acid vanillylamide and capsaicin on human vanilloid receptors

Pelargonic acid vanillylamide is like capsaicin a natural capsaicinoid from chili peppers and commonly used in food additives to create a hot sensation, even in self-defense pepper sprays and as an alternative to capsaicin in medical products for topical treatment of pain. Although the chemical structures of both compounds are similar, preclinical data suggest that capsaicin is the more potent compound. We therefore performed voltage-clamp recordings using cells transfected with the human vanilloid receptor TRPV1 in order to assess the responses of pelargonic acid vanillylamide and capsaicin at the receptor level. We provide evidence that at the molecular target TRPV1, the concentration-response curves, kinetics of current activation, as well as inhibition by the competitive antagonist capsazepine were not significantly different between the two capsaicinoids. We suggest that the different effects of the two capsaicinoids observed in previous studies may rather be due to different physicochemical or pharmacokinetic properties than to different pharmacological profiles at the receptor level.

The thermo-TRP ion channel family: properties and therapeutic implications

The thermo-transient receptor potentials (TRPs), a recently discovered family of ion channels activated by temperature, are expressed in primary sensory nerve terminals where they provide information about thermal changes in the environment. Six thermo-TRPs have been characterised to date: TRP vanilloid (TRPV) 1 and 2 are activated by painful levels of heat, TRPV3 and 4 respond to non-painful warmth, TRP melastatin 8 is activated by non-painful cool temperatures, while TRP ankyrin (TRPA) 1 is activated by painful cold. The thermal thresholds of many thermo-TRPs are known to be modulated by extracellular mediators, released by tissue damage or inflammation, such as bradykinin, PG and growth factors. There have been intensive efforts recently to develop antagonists of thermo-TRP channels, particularly of the noxious thermal sensors TRPV1 and TRPA1. Blockers of these channels are likely to have therapeutic uses as novel analgesics, but may also cause unacceptable side effects. Controlling the modulation of thermo-TRPs by inflammatory mediators may be a useful alternative strategy in developing novel analgesics.