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

Topical Diclofenac Versus Oral Ibuprofen Versus Diclofenac + Ibuprofen for Emergency Department Patients With Acute Low Back Pain: A Randomized Study

STUDY OBJECTIVE

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are useful for a variety of musculoskeletal injuries. It is not known whether topical NSAIDs should be used for patients presenting with acute nonradicular musculoskeletal low back pain.

METHODS

We conducted a randomized, placebo-controlled double-blind study in which patients 18 to 69 years of age visiting the emergency department (ED) with acute, nontraumatic, nonradicular, musculoskeletal low back pain were randomized at the time of discharge to treatment with 400 mg oral ibuprofen + placebo topical gel, 1% diclofenac topical gel + oral placebo, or 400 mg ibuprofen + 1% diclofenac topical gel. We measured outcomes using the Roland Morris Disability Questionnaire (RMDQ), a 24-item yes/no instrument about the effect of back pain on a respondent's daily activities. The primary outcome was change in RMDQ score between ED discharge and 2 days later. Medication-related adverse events were elicited by asking whether the study medications caused any new symptoms.

RESULTS

In total, 3,281 patients were screened for participation, and 198 were randomized. Overall, 36% of the population were women, the mean age was 40 years (standard deviation, 13), and the median RMDQ score at baseline was 18 (25th to 75th percentile: 13 to 22), indicating substantial low back-related functional impairment. In total, 183 (92%) participants provided primary outcome data. Two days after the ED visit, the ibuprofen + placebo group had improved by 10.1 (95% confidence interval [CI] 7.5 to 12.7), the diclofenac gel + placebo group by 6.4 (95% CI 4.0 to 8.8), and the ibuprofen + diclofenac gel by 8.7 (95% CI 6.3 to 11.1). The between-group differences were as follows: ibuprofen versus diclofenac, 3.7 (95% CI 0.2 to 7.2); ibuprofen versus both medications 1.4 (95% CI -2.1 to 4.9); and diclofenac versus both medications, 2.3 (95% CI -5.7 to 1.0). Medication-related adverse events were reported by 3/60 (5%) ibuprofen patients, 1/63 (2%) diclofenac patients, and 4/64 (6%) patients who received both.

CONCLUSION

Among patients with nontraumatic, nonradicular acute musculoskeletal low back pain discharged from an ED, topical diclofenac was probably less efficacious than oral ibuprofen. It demonstrated no additive benefit when coadministered with oral ibuprofen.

Multidisciplinary Guidelines for the Rational Use of Topical Non-Steroidal Anti-Inflammatory Drugs for Musculoskeletal Pain (2022)

(1) Background: Topical non-steroidal anti-inflammatory drugs (NSAIDs) are one of the primary drugs for treating musculoskeletal pain. However, there are currently no evidence-based recommendations about drug selection, drug administration, drug interactions, and use in special populations or other pharmacology-related content of such medications. To this end, the Chinese Pharmaceutical Association Hospital Pharmacy Professional Committee developed multidisciplinary guidelines on using topical NSAIDs to treat musculoskeletal pain. (2) Methods: The guidelines development process followed the World Health Organization guideline development handbook, the GRADE methodology, and the statement of Reporting Items for Practice Guidelines in Healthcare. The guideline panel used the Delphi method to identify six clinical questions to be addressed in the guidelines. An independent systematic review team conducted a systematic search and integration of evidence. (3) Results: Based on the balance between the benefits and harms of an intervention, the quality of the evidence, patient preferences and values, and resource utilization, the guideline panel developed 11 recommendations and nine expert consensuses on using topical NSAIDs to treat acute and chronic musculoskeletal pain. (4) Conclusions: Based on the effectiveness and overall safety of topical NSAIDs, we recommend patients with musculoskeletal pain use topical NSAIDs and suggest high-risk patients use topical NSAIDs, such as those with other diseases or receiving other concurrent treatments. The evidenced-based guidelines on topical NSAIDs for musculoskeletal pain incorporated a pharmacist perspective. The guidelines have the potential to facilitate the rational use of topical NSAIDs. The guideline panel will monitor the relevant evidence and update the recommendations accordingly.

Self-polishing antifouling coatings based on benzamide derivatives containing capsaicin

In this study, N-hydroxymethylbenzamide was alkylated with various aromatic compounds to obtain five novel benzamide derivatives containing capsaicin (BDCC), and the BDCC were incorporated into coatings as auxiliary agents. The relationships between properties and structures were discussed based on experimental and theoretical results. The theoretical results showed the optimized configurations of BDCC and confirmed that the benzene ring, phenolic hydroxyl, ester and amide groups were active sites. Experimental results indicated that the antimicrobial and antifouling effects of compounds b1, b2 and b3 were better than those of chlorothalonil, their MIC and MBC values were no more than 64 and 512 μg·mL-1, and their test panels were covered only with small amounts of dirt and biofilms; they worked well as green antifouling additives. The experimental and theoretical results showed that BDCC and BDCC antifouling coatings were effective and eco-friendly.

Topical Fixed-Dose Combinations: Current in vitro methodologies for pre-clinical development

The combination of two or more active pharmaceutical ingredients in the same dosage form - fixed-dose combination products - for topical administration represents a promising therapeutic approach for treating several pathologies, including pain. The pre-clinical development of fixed-dose combination products aims to characterize the interactions between the different APIs and ensure that the final medicinal product has the required safety characteristics. To this end, there are several regulatory accepted in vitro tests to assess the safety of medicinal products intended for cutaneous administration. In turn, the evaluation of anti-inflammatory activity should be based on models described in the scientific literature, as there are no models fully validated by competent entities. Therefore, the present work presents the information regarding accepted in vitro tests to assess the safety of topical products and the most used methods to assess anti-inflammatory activity. Additionally, a new approach to select a fixed-dose combination product with the potential to enhance the therapeutic effects of the individual active pharmaceutical ingredients is rationalized by integrating the overall effects on several targets relevant for inflammation and pain management in one numeric index.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

Background

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

Methods

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

Results

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

Conclusions

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Formulation design and mechanism study of hydrogel based on computational pharmaceutics theories

Formulation design and mechanism study of the drug delivery system (DDS) is an important but difficult subject in pharmaceutical research. The study of formulation factors is the most time- and labor-consuming work of formulation design. In this paper, a multiscale computational pharmaceutics strategy was developed to guide the systematic study of formulation factors of a typical polymer-based DDS, hydrogel, and further to guide the formulation design. According to the strategy, the combination of solubility parameter (δ) and diffusion coefficient (D) calculated by the AA-MD simulation was suggested as the general evaluation method for the matrix screening of the hydrogels at the pre-formulation stage. At the formulation design stage, the CG-MD simulation method was suggested to predict the morphology and drug-releasing behavior of the hydrogels under different formulation factors. The influence mechanism can be explained by the combination of multiple parameters, such as the microstructure diagram, the radius of gyration (Rg), the radial distribution function (RDF), and the free diffusion volume (V_diffusion). The simulation results are in good agreement with the in vitro release experiment, indicating that the strategy has good applicability.

TRPV1: Role in Skin and Skin Diseases and Potential Target for Improving Wound Healing

Skin is innervated by a multitude of sensory nerves that are important to the function of this barrier tissue in homeostasis and injury. The role of innervation and neuromediators has been previously reviewed so here we focus on the role of the transient receptor potential cation channel, subfamily V member 1 (TRPV1) in wound healing, with the intent of targeting it in treatment of non-healing wounds. TRPV1 structure and function as well as the outcomes of TRPV1-targeted therapies utilized in several diseases and tissues are summarized. In skin, keratinocytes, sebocytes, nociceptors, and several immune cells express TRPV1, making it an attractive focus area for treating wounds. Many intrinsic and extrinsic factors confound the function and targeting of TRPV1 and may lead to adverse or off-target effects. Therefore, a better understanding of what is known about the role of TRPV1 in skin and wound healing will inform future therapies to treat impaired and chronic wounds to improve healing.

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.

TRPV1-Targeted Drugs in Development for Human Pain Conditions

The transient receptor potential vanilloid-1 (TRPV1) is a non-specific cation channel known for its sensitivity to pungent vanilloid compound (i.e. capsaicin) and noxious stimuli, including heat, low pH or inflammatory mediators. TRPV1 is found in the somatosensory system, particularly primary afferent neurons that respond to damaging or potentially damaging stimuli (nociceptors). Stimulation of TRPV1 evokes a burning sensation, reflecting a central role of the channel in pain. Pharmacological and genetic studies have validated TRPV1 as a therapeutic target in several preclinical models of chronic pain, including cancer, neuropathic, postoperative and musculoskeletal pain. While antagonists of TRPV1 were found to be a valuable addition to the pain therapeutic toolbox, their clinical use has been limited by detrimental side effects, such as hyperthermia. In contrast, capsaicin induces a prolonged defunctionalisation of nociceptors and thus opened the door to the development of a new class of therapeutics with long-lasting pain-relieving effects. Here we review the list of TRPV1 agonists undergoing clinical trials for chronic pain management, and discuss new indications, formulations or combination therapies being explored for capsaicin. While the analgesic pharmacopeia for chronic pain patients is ancient and poorly effective, modern TRPV1-targeted drugs could rapidly become available as the next generation of analgesics for a broad spectrum of pain conditions.

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.