Systematic review of topical diclofenac for the treatment of acute and chronic musculoskeletal pain

Clinical Practice Guidelines for Topical NSAIDs in the Treatment of Sports Injuries

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to treat sports injuries, but evidence-based medical guidance for their standardized and rational use is lacking. This guideline working group identified clinically important issues, obtained the full opinions of patients and clinical staff, and discussed them with the expert group. Based on evidence from the literature, the "clinical practice guidelines for topical NSAIDs in the treatment of sports injuries" were formulated following the methods and principles of international guidelines. According to these guidelines, 7 clinical concerns were ultimately selected, and 22 recommendations were formed. These included the status, indications, contraindications, efficacy, combined application, use in special populations, adverse reactions, and countermeasures of topical NSAIDs in the treatment of sports injuries. The purpose of these guidelines is to provide evidence-based recommendations for practitioners in the fields of orthopedics, sports medicine, rehabilitation medicine, and sports science, as well as other fields, in the treatment of sports injuries to promote more standardized and rational use of topical NSAIDs.

Environmental fate and ecotoxicity of diclofenac degradation products generated by photo-assisted advanced oxidation processes

Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug (NSAID), poses environmental concerns due to its persistence, bioaccumulation potential, and transformation into toxic byproducts during oxidative and chlorination processes. This study investigated the photodegradation of DCF, both directly and in the presence of oxidants, to characterize the resulting degradation products and assess their potential environmental impact. The highest efficiency for direct UV photodegradation of DCF was observed at pH 5, while the addition of oxidants significantly accelerated the degradation rate. Among the advanced oxidation processes (AOPs) examined, the H₂O₂/UV system, with a DCF:H₂O₂ molar ratio of 1:30, exhibited the most effective performance in terms of DCF removal and total organic carbon (TOC) reduction. However, ecotoxicity assessments using Alivibrio fischeri, Daphnia magna, and Lemna minor revealed that AOPs generally increased the toxicity of the resulting solutions compared to untreated DCF. Toxicity analyses showed that post-reaction mixtures from AOPs involving NaOCl exhibited the highest toxic effects, consistent with forming specific transformation products identified as highly toxic by ECOSAR modeling. Additionally, the analysis of the physicochemical properties of DCF and its transformation products, including solubility and organic matter affinity, suggests a limited potential for long-range transport. These compounds are more likely to bind to sediments, reducing their mobility in groundwater.

Nonopioid analgesic use in older patients admitted for orthopedic rehabilitation

BACKGROUND

Multimodal analgesia (MMA) combines opioids with nonopioid analgesics (NOAs) to mitigate opioid-related adverse events and development of opioid use disorders. Although MMA has become the standard for orthopedic perioperative pain management, guidance is less clear for the approximately 15% of patients who go on to require inpatient orthopedic rehabilitation (IOR) postoperatively. The IOR population tends to be older and frailer and hence likely more vulnerable to adverse events. Little research has been done to shed light on how NOAs are used in this population.

OBJECTIVE

To characterize NOA prescribing in older versus younger adults during IOR admissions and to determine predictors of NOA prescribing in an older IOR population.

DESIGN

Retrospective case-control study.

SETTING

Two IOR wards at an academic rehabilitation hospital in Toronto, Canada.

PATIENTS

All patients aged ≥50 years admitted for an orthopedic indication between November 2019 and June 2021; the patients aged <65 group was included for comparative characterization of NOA prescribing versus older peers.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Medication use and adverse events, pain, and rehabilitation outcomes such as the Functional Independence Measure, discharge destination, and length of stay.

RESULTS

A total of 643 patient encounters were included; 48.2% used NOA. Age (odds ratio [OR]: 0.97; confidence interval [CI]: 0.95-0.99, p < .001) and prior NOA use (OR: 3.15; CI: 2.0-4.9, p < .001) were associated with NOA prescribing. Other positively associated factors included body mass index, psychiatric history, elective surgery, and admission from a specific referring hospital. Adverse events between NOA users and nonusers were similar.

CONCLUSIONS

NOA prescribing is heterogeneous and declines with age in IOR. This points to an opportunity to explore integrating NOA into opioid-sparing MMA protocols tailored to older IOR patients, along with further study of the safety and benefit of these regimens.

Unveiling the anxiolytic and analgesic effects of citronellal in Swiss mice: in vivo and in silico insights into COX and GABAA receptor pathways

This study aims to evaluate the analgesic and anxiolytic effects of citronellal (CTL) in Swiss mice using two new sensitive and economic mouse models along with possible molecular mechanisms through in silico studies. For this, we employed marble displacement and spiked-field apparatus to check the anxiolytic and analgesic effects, respectively. In silico studies were done against cyclooxygenase (COX) enzymes and GABAA receptor subunits. Findings suggest that the test sample CTL significantly reduced the number of marbles displaces (NMD), square crosses (NSC), paw massages (NPM), and escaping attempts (NEA) in animals than the control group. CTL exhibited better effects in the perforated-field study compared to the reference drug diclofenac sodium. In both cases, CTL (200 mg/kg) significantly reduced the test parameters when combined with the standard drugs (diazepam or diclofenac sodium). In in silico studies, CTL showed binding affinities of - 5.5, - 5.2, - 4.8, and - 4.8 kcal/mol with the COX1, COX2, and GABAA receptors (α2 and α3 subunits), respectively. Taken together, CTL may exert anxiolytic- analgesic-like effects on mice, possibly through the GABAA receptor and COXs interaction pathways. These new tools might be used to check the anxiolytic and analgesic properties of a wide variety of test substances.

Effect of Fluid Paraffin on the Formulation Properties of Pressure Sensitive Adhesive Formulations Containing Diclofenac Sodium

Understanding the relationship between the release characteristics of the active ingredient in the tape formulation and the pharmaceutical characteristics of the adhesive layer can optimize therapeutic efficacy and improve patient adherence. This study aimed to clarify the effect of liquid paraffine (LP)/styrene-isoprene-styrene (SIS) triblock copolymer ratio on pressure-sensitive adhesive (PSA) formulation properties, such as adhesive properties and drug release, with a certain amount of diclofenac sodium (DFS) and tackifier. The effects of changes in PSA composition in DFS-containing tape formulations on adhesive and drug release properties were evaluated. The viscoelasticity results showed rigid gel-like behavior at low angular frequencies regardless of the LP/SIS ratio, and deformable gel-like behavior at high angular frequencies, with a maximum plasticizing effect of LP up to an LP/SIS ratio of 3.7. The peel adhesion test results showed that peel adhesion was not affected, but indicated a decreasing trend by increasing the LP/SIS ratio in the presence of DFS. Drug release test results showed that DFS release increased up to 24 h for LP/SIS ratios of up to 3.7, but decreased when the LP/SIS ratio was 6. The results of the drug permeation tests were similar to those of the drug release tests. In conclusion, it is possible to change the drug release properties by changing the amount of LP in the tape formulation; however, no definitive correlation was found between the adhesive and drug release properties.

Emotions in search of words: Does alexithymia predict treatment outcome in chronic musculoskeletal pain?

Chronic pain, with its complex and multidimensional nature, poses significant challenges in identifying effective long-term treatments. There is growing scientific interest in how psychopathological and personality dimensions may influence the maintenance and development of chronic pain. This longitudinal study aimed to investigate whether alexithymia can predict the improvement of pain severity following a treatment-as-usual programme for chronic musculoskeletal pain over and above psychological cofactors (emotional distress, catastrophizing, and self-efficacy). A consecutive sample of 129 patients with diagnosed chronic musculoskeletal pain referred to two tertiary care centres was recruited and treated for 16 weeks. Clinical pain, psychological distress, self-efficacy, catastrophizing, and alexithymia were assessed with validated self-report measures at the first medical visit (T0) and at 16-week follow-up (T1). Compared with non-responder patients (n = 72, 55.8%), those who responded (i.e., reduction of >30% in pain severity; n = 57, 44.2%) reported an overall improvement in psychological variables except alexithymia. Alexithymia showed relative stability between baseline and follow-up within the entire sample and remained a significant predictor of treatment outcome even when other predictive cofactors (i.e., pain interference, depressive symptoms, and catastrophizing) were considered simultaneously. Our results suggest that identifying patients with a co-occurrence between alexithymia, depressive symptoms, catastrophizing, and the stressful experience of chronic pain can be clinically relevant in pain prevention and intervention programs.

Microemulsion-Based Polymer Gels with Ketoprofen and Menthol: Physicochemical Properties and Drug Release Studies

Ketoprofen is a non-steroidal, anti-inflammatory drug frequently incorporated in topical dosage forms which are an interesting alternatives for oral formulations. However, due to the physiological barrier function of skin, topical formulations may require some approaches to improve drug permeation across the skin. In this study, ketoprofen-loaded microemulsion-based gels with the addition of menthol, commonly known for absorption-enhancing activity in dermal products, were investigated. The main objective of this study was to analyze the physicochemical properties of the obtained gels in terms of topical application and to investigate the correlation between the gel composition and its mechanical properties and the drug release process. Microemulsion composition was selected with the use of a pseudoternary plot and the selected systems were tested for electrical conductivity, viscosity, pH, and particle diameter. The polymer gels obtained with Carbopol® EZ-3 were subjected to rheological and textural studies, as well as the drug release experiment. The obtained results indicate that the presence of ketoprofen slightly decreased yield stress values. A stronger effect was exerted by menthol presence, even though it was independent of menthol concentration. A similar tendency was seen for hardness and adhesiveness, as tested in texture profile analysis. Sample cohesiveness and the drug release rate were independent of the gel composition.

Pharmacological Topical Therapy for Intra-Oral Post Traumatic Trigeminal Neuropathic Pain: A Comprehensive Review

Background: The efficacy of topical treatments in alleviating neuropathic pain is well-established. However, there is a paucity of research on topical interventions designed specifically for intra-oral application, where the tissue composition differs from that of exposed skin. Methods: This comprehensive review endeavors to assess the extant evidence regarding the efficacy of topical treatments in addressing neuropathic pain within the oral cavity. Utilizing combinations of search terms, we conducted a thorough search across standard electronic bibliographic databases-MEDLINE (via PubMed), Embase, Google Scholar, and Up to Date. The variables under scrutiny encompassed topical treatment, local intervention, chronic oral and orofacial pain, and neuropathic pain. All pertinent studies published in the English language between 1992 and 2022 were included in our analysis. Results: Fourteen relevant manuscripts were identified, primarily consisting of expert opinions and case reports. The comprehensive review suggests that topical treatments, especially when applied under a stent, could be effective in mitigating neuropathic pain in the oral area. However, it is crucial to conduct further studies to confirm these preliminary results. The limitations of the reviewed studies, mainly the reliance on expert opinions, small sample sizes, inconsistent study designs, and a lack of long-term follow-up data, highlight the need for more rigorous research. Conclusions: Although initial findings indicate topical treatments may be effective for oral neuropathic pain, the limitations of current studies call for more thorough research. Further comprehensive studies are essential to validate the efficacy of these treatments, standardize procedures, and determine long-term results. This will provide clearer guidance for treating chronic neuropathic pain in the oral cavity.

Topical Treatment Is Effective and Safe for Acute Ankle Sprains: The Multi-Center Double-Blind Randomized Placebo-Controlled TRAUMED Trial

BACKGROUND

Topical NSAIDs are widely used to treat ankle sprains. Traumed (Tr14) gel is a multicomponent formulation, demonstrating inflammation-resolution properties.

METHODS

This multicenter, double-blind trial investigated the efficacy and safety of Tr14 gel versus placebo gel and non-inferiority versus 1% diclofenac gel, applied 3×/day for 7 days after acute lateral ankle sprain (EudraCT Number: 2016-004792-50). The primary outcome was AUC for pain on passive movement, assessed by VAS from baseline to Days 4 and 7.

RESULTS

The trial population included 625 patients aged 18 to 78 years. The AUC scores were 187.88 and 200.75 on Day 4 (p = 0.02) and 294.14 and 353.42 on Day 7 (p < 0.001) for Tr14 and placebo, respectively. For Tr14 compared to diclofenac, the AUC scores were 187.50 and 197.19 on Day 4 (p = 0.3804) and 293.85 and 327.93 on Day 7 (p = 0.0017), respectively. On the FAAM-ADL subscale, Tr14 was superior to placebo and non-inferior to diclofenac at all time points. Time to 50% pain improvement was lowest for Tr14 (6.0 days), compared to placebo (7.1 days) and diclofenac (7.0 days). Adverse events were uncommon and minor.

CONCLUSIONS

Tr14 gel is effective and safe in acute ankle sprains, compared to placebo gel and diclofenac gel, and has faster pain resolution.

TRIAL REGISTRATION

The trial was registered in clinicaltrialsregister.eu, EudraCT number 2016-004792-50 on 07.06.2017.

Synergistic interaction and activation of the opioid receptor-NO-cGMP-K+ channel pathway on peripheral antinociception induced by the α-Bisabolol-diclofenac combination

Introduction: The local peripheral combination of analgesic drugs with herbal derivatives may have beneficial effects. Information on the action mechanism of these interactions between drugs is scarce. Therefore, the main of the present study was to determine the pharmacological interaction and action mechanism of the combination α-Bisabolol and diclofenac. Methods: Rats were injected in the dorsal surface of the right hind paw with 1% formalin. Rats received subcutaneous injections in the dorsal surface of paw of vehicles or increasing doses of α-Bisabolol, diclofenac or their combination before formalin injection into the paw. Antinociception of the α-Bisabolol + diclofenac combination was evaluated with and without the local treatment of naloxone, metformin, NG-nitro-L-arginine methyl ester (L-NAME), 1H- (1,2,4)-oxadiazolo (4,2-a) quinoxalin-1-one (ODQ), glibenclamide, glipizide, 4-aminopyridine, tetraethylammonium, apamin, or charybdotoxin. Results: α-Bisabolol, diclofenac or α-Bisabolol-diclofenac combinations produced significant antinociception in the rat (p < 0.05). The experimental effective dose (ED) value of 109.2 µg/paw was different significantly of the theoretical effective dose (ED) of 245.7 µg/paw (synergism). Blockers significantly reverted the antinociception produced by the synergistic combination of α-Bisabolol and diclofenac. Discussion: Data showed a synergism of the α-Bisabolol-diclofenac combination and the activation of the opioid receptor-Nitric Oxide-cyclic GMP-K⁺ channels pathway and a biguanide-dependent mechanism in order to produce the potentiation of its peripheral antinociception in the formalin test.

A randomized, parallel control and multicenter clinical trial of evidence-based traditional Chinese medicine massage treatment VS External Diclofenac Diethylamine Emulgel for the treatment of knee osteoarthritis

BACKGROUND

Both massage and topically administered NSAIDs are safe and effective treatments for knee osteoarthritis (KOA); however, different massage technique sects in China caused assessment difficulties for the treatment of KOA. In order to standardize the massage techniques and procedures, we organized multi-disciplinary experts in China to acquire an evidence-based traditional Chinese medicine massage treatment of knee osteoarthritis. The purposes of this study will be to provide clinicians a complementary and alternative therapy for patients and to evaluate the efficacy and safety of evidence-based traditional Chinese medicine massage treatment of KOA compared to External Diclofenac Diethylamine Emulgel.

METHODS AND DESIGN

A randomized controlled trial in which 300 participants diagnosed with KOA will be recruited and randomly allocated to either the experimental group or the control group in a ratio of 2:1. Two hundred participants will receive evidence-based traditional Chinese medicine massage 2 sessions per week for 10 weeks as the experimental group, and 100 participants will receive External Diclofenac Diethylamine Emulgel 3-4 times per day for 10 weeks as the control group. The patients in the two groups will receive follow-up at two time points at 5 weeks and 10 weeks from the beginning of treatment, respectively. The MRI scans and X-ray will be performed at baseline and at the end of the intervention. The primary outcome will be the changes in the Western Ontario and McMaster Osteoarthritis Index (WOMAC). Secondary outcomes will be measured by the PRO scale for knee osteoarthritis based on the concept of traditional Chinese medicine (Chinese scale for knee osteoarthritis (CSKO)), X-ray evaluation, and MRI scan evaluation. The data of WOMAC and CSKO will be analyzed at the baseline, 5 weeks, and 10 weeks from the beginning of treatment. The data from MRI scans and X-rays will be analyzed at baseline and at the end of the intervention. The significance level sets as 5%. The safety of interventions will be evaluated after each treatment session.

DISCUSSION

This study will provide clinicians with much-needed knowledge for the treatment of KOA through a controlled trial.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1800014400 . Registered on 10 January 2018.

[Conservative treatment options for arthritis of the ankle : What is possible, what is effective?]

In this article the causes of arthritis in the region of the ankle are introduced and the conservative treatment options are described and discussed more extensively. The risks of treatment with nonopioid analgesics (NOPA) are presented in detail. The topical use of nonsteroidal anti-inflammatory drugs (NSAID) should always be considered in the clinical routine. If contraindications for oral NSAIDs are present, intra-articular treatment is a meaningful option. The best evidence is currently available for viscosupplementation but the study situation for the use of platelet-rich plasma (PRP) is still not sufficiently comprehensive and there are only a few case reports on the use of mesenchymal stem cells..

Safety and Efficacy of the FLECTOR (Diclofenac Epolamine) Topical System in Children with Minor Soft Tissue Injuries: A Phase IV Non-randomized Clinical Trial

Background and Objective

A topical formulation of diclofenac (FLECTOR diclofenac epolamine topical system (FDETS)) is approved in adults for the treatment of acute pain due to minor strains, sprains, and contusions; however, its safety and efficacy have not been investigated in a pediatric population. This study assessed the safety and efficacy of the FLECTOR (diclofenac epolamine) topical system in children.

Methods

This was an open-label, single-arm, phase IV study at ten USA-based family medicine or pediatric practices in children aged 6–16 years with a clinically significant minor soft tissue injury sustained within the preceding 96 h and at least moderate spontaneous pain on the Wong-Baker FACES^® Pain Rating Scale. The FLECTOR topical system was applied twice daily until pain resolution or Day 14. The primary endpoint was local tolerability and systemic safety. Key secondary endpoints were diclofenac plasma concentrations and analgesic efficacy.

Results

104 patients were enrolled; 52 were 6–11 years old, and 52 were 12–16 years old (mean age 11.6 years). The maximum tolerability score experienced by any patient was 1 (faint redness). Fourteen adverse events (none serious) in nine patients (8.7%) were considered possibly treatment-related. Reduction in pain during the study was somewhat greater for patients aged 6–11 versus 12–16 years (p < 0.011). The diclofenac plasma concentration tended to be higher in the younger age group compared with older patients: 1.83 versus 1.46 ng/mL at the first assessment and 2.49 versus 1.11 ng/mL at the last assessment (p = 0.002).

Conclusion

The FLECTOR topical system safely and effectively provided pain relief for minor soft tissue injuries in the pediatric population, with minimal systemic nonsteroidal anti-inflammatory drug exposure and low potential risk of local or systemic adverse events.

Clinical Trial Registration

ClinicalTrials.gov identifier NCT02132247.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40261-021-01101-x.

In this post-marketing clinical trial, the safety and efficacy at relieving pain of the FLECTOR diclofenac epolamine topical system (FDETS), a nonsteroidal anti-inflammatory drug (NSAID) formulation in a medicated patch, was assessed in a pediatric population (aged 6–16 years) with clinically significant minor soft tissue injuries. The safety and efficacy profiles in the pediatric population were consistent with previous data in adults. Both diclofenac plasma concentrations and reduction in pain during the study were greater for younger patients (aged 6–11 vs. 12–16 years), but plasma concentrations were much less than after diclofenac was taken orally in previous studies. This study shows that FDETS can safely and effectively provide pain relief for soft tissue injuries in children, with minimal systemic NSAID exposure and a low potential risk of either local or systemic adverse events.

Polyhydroxyalkanoates, bacterially synthesized polymers, as a source of chemical compounds for the synthesis of advanced materials and bioactive molecules

Research into polyhydroxyalkanoates (PHAs) is growing exponentially. These bacterially derived polyesters offer a spectrum of possible applications, such as in manufacturing of daily-use objects, production of medical devices and implantable objects, or as synthons in chemical and pharmaceutical industries. Thanks to their broad physicochemical features, PHAs can be seen as polymers of the future, which can replace traditional petrochemical equivalents. As they are synthesized by bacteria through fermentation processes, these polyesters can be obtained from virtually any carbon source in a sustainable manner. Characterized by biodegradability and biocompatibility, they are used in many industries, ranging from production of everyday objects to medical applications. Furthermore, as they are built from bioactive monomers, namely (R)-3-hydroxyacids, they provide a platform for the synthesis of advanced chemical compounds. In this mini review, the reader will be acquainted with recent studies conducted at the Jerzy Haber Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences in collaboration with other groups that have contributed to the development of PHA-based medical materials, bioactive molecules and novel green solvents derived from PHA monomers.Key points• Polyhydroxyalkanoates are emerging polymers for biomedical applications• Polyhydroxyalkanoates can be modified easily to provide novel materials• (R)-3-Hydroxyacids are good synthons for bioactive substances and green solvents.

Comparison of the Efficacy and Safety of Ketoprofen Plaster and Diclofenac Plaster for Osteoarthritis-Related Knee Pain: A Multicenter, Randomized, Active-Controlled, Open-Label, Parallel-Group, Phase III Clinical Trial

PURPOSE

To compare the efficacy and safety of ketoprofen plasters and diclofenac plasters after 3 weeks of administration in patients with osteoarthritis-related knee pain.

METHODS

This multicenter, randomized, active-controlled, open-label, parallel-group, noninferiority phase III study randomized 236 adults with osteoarthritis-related knee pain for 3 weeks with ketoprofen plaster 30 mg twice daily (n = 118) or diclofenac plaster 15 mg once daily (n = 118). The primary efficacy end point was the mean change from baseline to week 3 in the mean knee pain intensity score during walking, as measured by a 100-mm visual analog scale with a predefined noninferiority margin of 10.0 mm. Secondary end points included changes in knee pain intensity score during walking (weeks 1 and 2) and at rest (weeks 1, 2, and 3), Knee Injury and Osteoarthritis Outcome Score, Patient Global Impression of Improvement scale assessments, and frequency of rescue medication use after 2 and 3 weeks of treatment.

FINDINGS

A total of 223 patients (115 in the ketoprofen group and 108 in the diclofenac group) were included in the per-protocol analysis. After 3 weeks of treatment, the least squares mean change from baseline in knee pain intensity scores during walking was -35.9 (95% CI, -39.7 to -32.2) in the ketoprofen group and -31.7 (95% CI, -35.5 to -27.9) in the diclofenac group, with noninferiority found (least squares mean difference, -4.2; 95% CI, -9.6 to 1.1). Ketoprofen significantly (P < 0.05) reduced the pain intensity score at rest after 2 and 3 weeks of treatment compared with diclofenac. No statistically significant difference was found between the groups in terms of changes in pain intensity score during walking at weeks 1, 2, and 3. The mean Patient Global Impression of Improvement score was statistically significant (P < 0.001) in favor of ketoprofen after 2 and 3 weeks of treatment. In addition, the Knee Injury and Osteoarthritis Outcome Score improved in both groups, and no statistically significant difference was found between the groups in terms of frequency of rescue medication use. The overall adverse event profile of the groups was similar, and no difference was found in skin reaction rates between the 2 groups.

IMPLICATIONS

Ketoprofen plasters can be effectively and safely administered to patients with osteoarthritis-related knee pain.

Application of Dimethyl Sulfoxide as a Therapeutic Agent and Drug Vehicle for Eye Diseases

Dimethyl sulfoxide (DMSO) is an amphipathic molecule widely used as a solvent for water-insoluble substances, cryopreserving, and cell-biological therapies. It has known properties as an inducer of cellular differentiation, a free radical scavenger, and a radioprotectant. In addition, DMSO is used for its various therapeutic and pharmaceutical properties, such as anti-inflammatory, local and systemic analgesic, antibacterial, antifungal, antiviral, and membrane penetration enhancement agents. DMSO treatment can be given orally, intravenously, or topically for a wide range of indications. The administration of DMSO exhibits favorable outcomes in human eye diseases with low to none observed ocular or systemic ocular toxicity. Nevertheless, DMSO is an essential and nonpatentable potential therapeutic agent that remains underexplored and ignored by pharmaceutical developers and ophthalmologists. This current review takes data from experimental and clinical studies that have been published to substantiate the potential therapeutic efficacy of DMSO and stimulate the research of its application in clinical ophthalmology. Given that DMSO is inexpensive, safe, and easily formulated into therapeutic medicinal products and conventional ophthalmological drugs, this compound should be further explored and studied in the treatment of a variety of acute and chronic ocular disorders.

Comprehensive Review of Topical Analgesics for Chronic Pain

PURPOSE OF REVIEW

Topical analgesics are a non-opioid option for the treatment of chronic pain conditions including neuropathic pain, musculoskeletal pain, and osteoarthritis. There are many topical medications available; however their efficacy is variable. This article reviews the various topical analgesics, their mechanisms of action, and their efficacy.

RECENT FINDINGS

Studies have found topical NSAIDs are useful in treating acute musculoskeletal pain syndromes (strains and sprains) and show some efficacy in treating hand and knee osteoarthritis (Derry et al. Cochrane Database Syst Rev 5:CD008609, 2017). Topical capsaicin 8% has been shown to be efficacious in the treatment of postherpetic neuralgia, painful diabetic peripheral neuropathy, and HIV-neuropathy (Derry et al. Cochrane Database Syst Rev 1:CD007393, 2017). Topical lidocaine has been widely studied and found to reduce pain in patients with postherpetic neuralgia (Knezevic et al. Pain Manag 7:537-58, 2017). Although many other topical analgesics are available, there is limited data to support the efficacy of other agents. Topical analgesics are a relatively benign treatment for chronic pain conditions including neuropathic pain, musculoskeletal, and myofascial pain. There is evidence to support the use of topical NSAIDs, high concentration topical capsaicin, and topical lidocaine for various painful conditions.

The burden of musculoskeletal pain and the role of topical non-steroidal anti-inflammatory drugs (NSAIDs) in its treatment. Ten underpinning statements from a global pain faculty

This document presents the conclusions of a detailed discussion on the role of topical NSAIDs during a round table Global Pain Faculty meeting held in Amsterdam in 2019 and subsequent discussions online. The aim of this evidence-based document is to describe the impact of musculoskeletal pain both in terms of the large numbers of sufferers and its economic impact. The document considers the place of topical therapies alongside other pharmacological and non-pharmacological treatments and presents the evidence for the benefits and harms of topical NSAIDS including indicators of efficacy for three main topical NSAIDs- diclofenac, ibuprofen and ketoprofen - based on almost 15,000 participants in randomized controlled trials for acute and chronic musculoskeletal pain. These topical NSAIDs have the largest body of evidence. For acute pain, numbers needed to treat to achieve at least 50% reduction in pain are as follows with 95% confidence intervals in brackets: Diclofenac emulgel 1.8(1.5-2.1) (5170 participants), Ibuprofen gel 2.7 (1.7-4.2) (436 participants), Ketoprofen gel 2.2 (1.7-2.8) (683 participants). For chronic pain, the NNTs are Diclofenac any formulation 9.5(7-14) (5995 participants). Ketoprofen 6.9(5.5-9.3) (2573 participants). Randomized controlled trial evidence suggests that adverse events for active topical NSAIDs are similar to placebo. Finally the gaps in knowledge are considered with suggestions on how further research might help. The global pain faculty was brought together by GSK under an unrestricted educational grant.

Pain characteristics and biomarkers in treatment approaches for osteoarthritis pain

Osteoarthritis (OA) is a progressive disease and OA pain intensity is related to ongoing pathophysiological changes. However, OA pain is complex and multimodal; its characteristics, including severity, localization and the stimuli that elicit it, can change as the disease progresses and differ greatly among patients. Understanding mechanisms underlying specific pain characteristics may help guide clinicians in choosing appropriate treatments, targeting treatments to those patients most likely to benefit. Associations have been demonstrated between biomarkers and some characteristics of OA pain, and to processes linked to the shift in pain characteristics over the course of OA. This article examines how understanding OA pain characteristics and their relation to the disease process could inform treatment choice when applying well-established treatment guidelines.

Alexithymia and Somatization in Chronic Pain Patients: A Sequential Mediation Model

OBJECTIVE

To investigate whether chronic pain (CP) patients with somatization reported higher alexithymic traits than those without somatization and to study the different relationships between psychological characteristics, pain, health-related quality of life (HRQL), and somatization.

METHOD

A consecutive sample of 134 CP treatment-seeking outpatients were evaluated for alexithymia (TAS-20), somatization (PHQ-15), distress (HADS), HRQL (SF-12), and pain (BPI).

RESULTS

Patients with somatization (37.04%) reported significantly higher TAS-20 total scores (p < 0.001) and difficulty in identifying feelings (DIF) (p < 0.001) than those without somatization. The somatizer group had also a significantly higher disease duration, severity and interference of pain, distress, and lower HRQL than the non-somatizer group. Hierarchical regression analysis showed that although distress, pain interference and the mental HRQL component are closely related to somatization (R 2 = 0.55), DIF was the strongest predictor of severity of somatization (β = 0.31). A sequential indirect effect from DIF to somatization via distress symptoms and pain interference turned out to be significant [95% CI (0.01, 0.09)]. Support was also found for sequential mediation paths from DIF to somatization via distress and mental HRQL [95% CI (0.01, 0.11)].

CONCLUSIONS

Our results pointed-out that alexithymia, particularly DIF, may be major factor for somatization risk in CP patients. Longitudinal observations are needed for evaluating the role of alexithymia in clinical outcomes.

Topical Diclofenac, an Efficacious Treatment for Osteoarthritis: A Narrative Review

Multiple head-to-head trials have demonstrated that topical nonsteroidal anti-inflammatory drugs (NSAIDs), including topical diclofenac, provide at least equivalent analgesia, improvement in physical function, and reduction of stiffness compared with oral NSAIDs in osteoarthritis and have fewer systemic adverse events. While efficacy of topical diclofenac in osteoarthritis is well established, understanding of the time to onset of action, duration of effect, and the minimum effective concentration is limited. Factors likely to influence these parameters include drug penetration and localization. Diclofenac concentrations in the joint tissues are likely to be more relevant than plasma concentrations. However, although diclofenac penetrates and is retained in these "effect compartments" at the site of inflammation and drug activity, no specific minimum effective concentration of diclofenac in plasma or synovial tissue has been identified. Recent evidence suggests that a reduction in inflammatory markers may be a better predictor of efficacy than plasma concentrations. This narrative review explores existing evidence in these areas and identifies the gaps where further research is needed. Based on our findings, topical NSAIDs such as diclofenac should be considered as a guideline-supported, generally well-tolerated, and effective first-line treatment option for knee and hand OA, especially for older patients and those who have comorbid conditions and/or risk factors for various systemic (gastrointestinal, hepatic, renal, or cardiovascular) adverse events associated with oral NSAIDs, particularly at high doses and with long-term use.