Review of the pharmaceutical properties and clinical effects of the topical NSAID formulation, diclofenac epolamine

Treatment of rheumatic musculoskeletal disorders

Non-medicinal therapies with water, salts, exercise, massage, supportive devices, and electricity have been used for centuries and continue to be of benefit for some people with musculoskeletal disorders. Historical texts refer to the two electuaries mithridatium and theriaca as early therapeutic attempts of man to provide relief of musculoskeletal symptoms and attempt disease cures. For over 200 years, morphine-derived products have been used for musculoskeletal pain. The development of acetyl salicylic acid was a major breakthrough in joint pain management. This was followed by the introduction of nonsteroidal anti-inflammatory agents, paracetamol, and the use of corticosteroids. The gold-based compounds were the initial disease-modifying drugs and have been followed by the highly successful biologics agents. The basic objectives of musculoskeletal pain management include: reduction or elimination of joint pain; improvement or restoration of joint function and mobility; improvement of muscle strength to protect cartilage, ligaments, and joint capsule; prevention and reduction of damage to joint cartilage and supporting structures.

Case Report: Persistent Pulmonary Hypertension of the Newborn and Narrowing of the Ductus Arteriosus After Topical Use of Non-Steroidal Anti-Inflammatory During Pregnancy

Background: The use of non-steroidal anti-inflammatory drugs (NSAIDs) during the third trimester of pregnancy can cause premature constriction of the ductus arteriosus. This report describes a case of in utero narrowing of the ductus arteriosus (DA) diagnosed postnatally in a baby with Persistent Pulmonary Hypertension of the Newborn (PPHN), after maternal use of Diclofenac-Epolamine 140 mg patch during the second and third trimester.

Case Presentation: A fetal ultrasounds revealed an enlarged hypertrophic right ventricle at 32 weeks of gestation. Detailed questioning of the mother highlighted that topical Diclofenac (FLECTOR^®) had been used at 26 and at 31 weeks of gestation. An echocardiography performed 8 h postnatally showed supra-systemic pulmonary hypertension, a restrictive ductus arteriosus and a dilated right ventricle. The newborn was treated by inhaled nitric oxide and oral Sildenafil and was discharged from hospital on day 24. He had a complete normalization of his pulmonary vascular resistance on day 48.

Conclusion: This case illustrates the potential fetal and neonatal complications associated with maternal topical Diclofenac medication during pregnancy resulting in antenatal closure of the DA.

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.

Topical NSAIDs for acute local pain relief: in vitro characterization of drug delivery profiles into and through human skin

OBJECTIVE

The efficacy of topical nonsteroidal anti-inflammatory drugs (NSAIDs) relates not only to the individual NSAID used but also to differences in formulation design. The aim of this study was to investigate the fundamental differences in ibuprofen and diclofenac drug delivery vehicles, specifically gels and plasters, compared to a recently launched 200 mg ibuprofen medicated plaster and characterize the resulting dermatologic-pharmacokinetic profiles into and through ex vivo human skin layers.

METHODS

In vitro skin permeation testing over 24 h and sacrificial timepoint penetration experiments (at 1, 4, 8, 12, and 24 h) were conducted using an automated flow-through diffusion cell system. The amount of drug delivered to the epidermis, dermis, and receptor solution (representing deeper tissue) was determined by liquid chromatography-tandem mass spectrometry. Skin protein binding of ibuprofen and diclofenac was investigated by spiking skin homogenate with increasing concentrations of each drug and determining the fraction unbound.

RESULTS

Differences were observed in the amount of drug recovered at sacrificial timepoints and rate at which drug was delivered to the target site between plaster and gel formulations of ibuprofen and diclofenac and between plaster formulations of the same drug (ibuprofen). While the amount of drug quantified at sacrificial timepoints did not necessarily determine in vivo flux rates, differences in drug distribution within the skin layers indicated where drug reservoirs were formed.

CONCLUSIONS

These findings highlight the importance of intelligent formulation design in determining NSAID delivery through skin layers. Further work is required to quantify drug delivery into deeper tissues and the resultant local anti-inflammatory effects.

Electroporation-enhanced transdermal drug delivery: Effects of logP, pKa, solubility and penetration time

Electroporation is an important physical technique to improve drug transdermal delivery, although its mechanism remains unclear. Here, some types of polar drugs, including aspirin, diclofenac sodium, metformin hydrochloride, ibuprofen and zidovudine, were used as the model drugs for the exploration of electroporation mechanisms. Electroporation had great influences on the structure of stratum corneum to improve the cumulative permeability due to the formation of pores maintaining for at least 2 h, depending on the power and time, and then the permeation gradually recovered to the normal value after 12 h. A mathematical model was firstly established to exhibit the relationship between the electroporation-improving cumulative permeation and the physiochemical properties of the model drugs, involving oil-water partition coefficient (logP), dissociation constant (pKa) and solubility (S). Increased cumulative permeation depended on increased S, decreased logP and pKa. Electroporation is an effective physical technique to improve transdermal drug delivery depending on itself and the properties of drugs.

Development of a Novel Simple Gel Formulation Containing an Ion-Pair Complex of Diclofenac and Phenylephrine

BACKGROUND AND AIM

Since the pharmacological effects of diclofenac (DF) are short-lived because of its short half-life, prolongation of the pharmacological effect in a topical formulation is needed for more appropriate clinical use. For the enhancement of dermal accumulation and prolongation of the pharmacological effect of drugs, the aim of this study was to develop a simple gel formulation containing an ion-pair complex of DF and phenylephrine (PHE), which induce constriction of the vascular smooth muscles.

MATERIALS AND METHODS

The ion-pair complex was prepared by mixing sodium DF and an ethanolic solution of PHE. The formed complex was characterized by powder X-ray diffraction (PXRD) and Fourier-transform infrared (FT-IR) spectroscopy. The ion-pair complex for the gel formulation was prepared by mixing an equimolar concentration of 50% 1,3-butylene glycol and distilled aqueous solution of 2% xanthan gum, which was characterized by proton nuclear magnetic resonance (1H-NMR). Skin permeation and accumulation of DF and PHE were evaluated by in vitro and in vivo studies.

RESULTS

From the results of PXRD and FT-IR, it was suggested that new crystalline peaks formed by the ion-pair complex and their complex interacted with the carboxyl group in DF and the amino group in PHE. In the gel formulation, the ion-pair complexes were detected by 1H-NMR. The ion-pair complex enhanced the accumulation of DF in the skin in the in vitro study. On the other hand, PHE accumulation in the dermis increased with the ion-pair complex, as exhibited by the in vivo study.

CONCLUSION

A new gel formulation containing the ion-pair complex of DF and PHE was developed, which improved the accumulation of DF in skin.

The dorsal skinfold chamber: A valuable model for the in vivo evaluation of topical formulations

In this study, we introduce the mouse dorsal skinfold chamber model as a valuable approach for the in vivo evaluation of topical formulations. For this purpose, dorsal skinfold chambers were implanted into BALB/c mice. Tumor necrosis factor (TNF)-α was administered to the chamber tissue for the local induction of inflammation followed by the application of diclofenac-containing or diclofenac-free (control) gel onto the skin of the chamber backside. Intravital fluorescence microscopy was repetitively performed throughout an observation period of 24 hours to study macromolecular leakage, leucocyte-endothelial cell interactions and microhaemodynamic parameters. In addition, infiltration of the inflamed tissue with different immune cell subtypes was assessed by immunohistochemistry. In a second set of experiments, the effect of dermal application of a diclofenac-containing gel on photochemically induced thrombus formation was analysed. It was observed that macromolecular leakage, numbers of adherent leucocytes and tissue infiltrating myeloperoxidase (MPO)-positive neutrophilic granulocytes and CD68-positive macrophages were significantly reduced in dorsal skinfold chambers treated with diclofenac-containing gel when compared to controls. Moreover, the diclofenac-containing gel exerted an anti-thrombotic activity, as indicated by a significantly prolonged complete vessel occlusion time. These findings demonstrate that the mouse dorsal skinfold chamber represents a valid and versatile tool to evaluate the effects of topical formulations in vivo.

Rationale and evidence for the incorporation of heparin into the diclofenac epolamine medicated plaster

OBJECTIVE

The nonsteroidal anti-inflammatory drug (NSAID) diclofenac epolamine (DHEP) formulated as a topical patch has demonstrated efficacy and safety in the localized treatment of acute pain from minor strains, sprains and contusions, and for epicondylitis and knee osteoarthritis. The glycosaminoglycan heparin enhances the activity of topical NSAIDs formulated as a medicated plaster, even in the absence of any significant release of heparin. Therefore, DHEP plus, a new formulation of the DHEP medicated plaster containing a small amount of heparin sodium as excipient, has been developed.

METHODS

We reviewed the pivotal and supportive studies of the clinical development program of the new patch and evaluated the role of heparin as an enhancer in the treatment of localized pain/inflammation of musculoskeletal structures, associated with post-traumatic and/or rheumatic conditions.

RESULTS

The data was consistent with the concept that heparin increased the clinical activity of the DHEP plus medicated plaster versus the reference DHEP medicated plaster through improved bioavailability due to enhanced movement of diclofenac from the plaster. Both DHEP formulations have the same dissolution profile, indicating that heparin does not change the physical and chemical characteristics of the plaster. Permeation testing showed that heparin is not released from the DHEP plus medicated plaster. Efficacy studies showed that the DHEP plus medicated plaster was significantly more effective in reducing pain than the reference marketed DHEP medicated plaster.

CONCLUSIONS

The benefit/risk assessment of DHEP plus 180 mg medicated plaster is favorable, with a safety profile equal to placebo and improved efficacy over the reference marketed DHEP medicated plaster.

Diclofenac in the treatment of pain in patients with rheumatic diseases

Diclofenac, a phenylacetic acid derivative, is a drug demonstrating high efficacy after oral administration in the treatment of pain and physical disability in rheumatic diseases. In view of the adverse effects associated with using diclofenac, it is necessary to consider all known drug safety information before the drug is selected for therapy and the dosage regimen is set for individual patients. Selecting an oral dosage form with specific properties determined by excipients is a method to improve the availability of the drug substance and, at the same time, minimize adverse drug reactions. An alternative to tablet or capsule dosage forms is diclofenac application to the skin. The proven efficacy of this method is further improved through the use of transdermal penetration enhancers and vehicle ingredients which provide dosage forms with specific physical properties.

A Pharmacokinetic Study of an Ibuprofen Topical Patch in Healthy Male and Female Adult Volunteers

The pharmacokinetics of a novel locally applied ibuprofen topical patch was evaluated. Healthy subjects (n = 28) were administered a 200-mg ibuprofen patch every 24 hours for 5 days, and steady-state pharmacokinetics was determined. The amount of ibuprofen remaining in the patch following each patch removal was also assessed. The maximum steady-state drug concentration and area under the concentration curve from time 0 on day 5 (t = 0) to the 24-hours sample on day 6 were 514 ng/mL (95% CI 439 to 603 ng/mL) and 9.78 kg·h/mL (95% CI 8.43 to 11.4 kg·h/mL), respectively. Maximum ibuprofen concentration on day 5 occurred at 20 hours post-patch application. No evidence of drug accumulation was observed, and steady state was achieved between days 2 and 5. Ibuprofen levels attenuated rapidly to baseline within 24 hours after treatment discontinuation. The amount of ibuprofen remaining in the patch was high (≥80%). Treatment-emergent adverse events were generally mild, with the most prevalent being headache (n = 6; 21.4%). Only 4 TEAEs were considered related to the ibuprofen patch: paresthesia (n = 1), headache (n = 2), and pruritic rash (n = 1). The study found that the systematic absorption of ibuprofen from a 200-mg patch was low and that the levels of ibuprofen leaving the patch over a 24-hour period are consistent with levels required for therapeutic relief as shown in other studies.

Patient-Physician Differences in Desired Characteristics of NSAID Plasters: An Online Survey

In Japan, adhesive skin plasters containing nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used to treat pain of musculoskeletal origin. There are many reports on their efficacy but few on patients' impressions of usability or levels of satisfaction. Objectives. To elucidate the differences in perception between patients and physicians concerning NSAID plasters. Subjects. We conducted two surveys about NSAID plasters on patients and physicians. 600 patients currently using plasters and 200 physicians currently prescribing NSAID plasters were studied. Methods. Questionnaire included items concerning usage, efficacy and side effects, site and intensity of their pain, pain management strategies, characteristics they desired from NSAID plasters, and their satisfaction with them. Results. The characteristic most frequently reported as desirable by patients was analgesic efficacy, followed by avoiding skin irritation and low medication cost. The characteristics most frequently reported as desirable by physicians were analgesic efficacy, alignment with patient preference, safety to skin, and comfort when applied. Our survey revealed that both patients and physicians prioritized analgesic efficacy of NSAID plasters. However, approximately half of the patients and physicians were unsatisfied with the analgesic efficacy of plasters. Conclusions. Physicians may improve patient satisfaction by discussing analgesic efficacy, skin complications, and price with patients before prescription.

Skin penetration and tissue permeation after topical administration of diclofenac

OBJECTIVE

Topical delivery of drugs is an alternative to oral administration, often with similar efficacy but potentially a more favorable tolerability profile. However, topical formulations need to be able to penetrate the skin and permeate to the target areas in quantities sufficient to exert a therapeutic effect. Many factors can affect this process, including the physicochemical properties of the drug, the formulation used, and the site and mode of application. It is believed that measurement of drug concentrations at the sites of action may be an indicator of their likely efficacy. This review addresses these issues, with reference to topically administered diclofenac in osteoarthritis.

METHODS

Articles relevant to this review were identified after a systematic search of Medline and Embase, using the key words "diclofenac", "topical administration" and "osteoarthritis" in the search strategy.

RESULTS

The sparse data available indicate that topical diclofenac can penetrate and permeate to deeper tissues, with a lower plasma to tissue ratio than oral diclofenac. The tissue diclofenac levels after topical delivery are sustained over time (at least several hours). However, there is not enough data to establish how diclofenac levels in the joint compare with IC₅₀ levels (50% of the maximum inhibition of prostaglandin synthesis) established following oral administration.

CONCLUSIONS

After topical application, diclofenac can penetrate the skin and permeate to deeper tissues, where it reaches a concentration that appears to be sufficient to exert a therapeutic effect. More robust methods are required for in vivo characterization to better estimate the clinical efficacy of topically applied drugs.

The Effectiveness of Diclofenac Sodium in the Treatment of Mondor's Disease of the Breast: The Topical Patch Compared to the Oral Capsules

Mondor's disease of the breast is a rare, benign sclerosing superficial thrombophlebitis of the subcutaneous veins of the anterior or lateral chest wall, which is treated conservatively. We aim in this study to evaluate the outcome and effectiveness of our treatment protocol using oral diclofenac sodium and topical diclofenac sodium patch in 172 patients. A retrospective database analysis of 172 female patients between January 2001 and December 2010 was done. The treatment protocol consisted of group 1: treatment by oral diclofenac sodium 100 mg once daily for 3 weeks. Group 2: treatment by diclofenac sodium patches for 8 hours twice daily (morning and evening) for 1 week. The patients were instructed to document the time as soon as pain relief is achieved following the patch application and the intake of the oral dose. The incidence rate was 2.49%. Diclofenac sodium patch was statistically found to be significantly better in subsiding the inflammatory process of the veins, relieving the pain, and enhancing faster healing rate. We conclude that diclofenac sodium patch showed a promising role in the treatment of Mondor's disease of the breast by significantly decreasing the inflammatory process due to its transdermal migration action within a short period and the ability to reach a high local concentration. It achieved the best results for rapid relief of pain and disease regression compared to the oral capsules. Therefore, our protocol was changed to implement diclofenac sodium patch as the first choice in treating Mondor's disease of the breast.

Efficacy and safety of diclofenac sodium 2% topical solution for osteoarthritis of the knee: a randomized, double-blind, vehicle-controlled, 4 week study

OBJECTIVE

Nonsteroidal anti-inflammatory drugs (NSAIDs) are standard therapy for osteoarthritis (OA). Topically applied NSAIDs reduce systemic exposure compared with oral NSAIDS, and European guidelines recommend their use. The NSAID diclofenac is available in a range of topical formulations. Diclofenac 1% gel and 1.5% four times daily and 2% twice daily (BID) solutions are approved to reduce pain from OA of the knee(s). The objective of this study was to investigate the efficacy and safety of diclofenac sodium 2% topical solution BID versus vehicle control solution for treating pain associated with OA of the knee.

RESEARCH DESIGN AND METHODS

A phase II, 4 week, randomized, double-blind, parallel-group, two-arm, vehicle-controlled study compared pain relief with diclofenac sodium 2% topical solution versus control (vehicle only) in patients aged 40 to 85 years with radiographically confirmed primary OA of the knee.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01119898.

MAIN OUTCOME MEASURES

The primary efficacy outcome was change from baseline to the final visit in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. Secondary outcomes included additional WOMAC subscales and patient global assessment of OA. Treatment-emergent adverse events (TEAEs), skin irritation, and vital signs were assessed and collected throughout the study.

RESULTS

Of 260 patients randomized, 259 received ≥1 dose of study drug. Significantly greater reductions in least-squares mean (standard error) WOMAC pain scores were observed for diclofenac-treated (-4.4 [0.4]) versus vehicle-treated patients (-3.4 [0.4]) at the final visit (p = 0.040). The most commonly reported TEAEs were administration site conditions. The vehicle-treated group experienced slightly more TEAEs than the active treatment group (38.8% vs. 31.5%). No serious adverse events were reported.

CONCLUSIONS

Administration of diclofenac sodium 2% topical solution BID resulted in significantly greater improvement in pain reduction in patients with OA of the knee versus vehicle control and was generally well tolerated.

Low-dose SoluMatrix diclofenac : a review of safety across two Phase III studies in patients with acute and osteoarthritis pain

INTRODUCTION

Similar to other NSAIDs, diclofenac is associated with serious dose-related cardiovascular, gastrointestinal, and renal adverse events. Low-dose SoluMatrix diclofenac , containing submicron particles of diclofenac, was developed to provide effective analgesia at lower drug doses compared with currently available NSAIDs.

AREAS COVERED

The efficacy and safety of low-dose SoluMatrix diclofenac was evaluated in two randomized, placebo-controlled Phase III studies: a study in patients with acute pain following bunionectomy surgery and a study in patients with osteoarthritis pain of the hip or knee. In this review article, we summarize safety data from these studies.

EXPERT OPINION

The safety results from the Phase III studies indicate that all dosing regimens of low-dose SoluMatrix diclofenac up to 12 weeks are generally well tolerated. Few serious gastrointestinal, cardiovascular, renal, or hepatic adverse events commonly associated with NSAID use were reported in these studies. Although not directly compared, the safety of SoluMatrix diclofenac was similar to findings for other diclofenac drug products. The potential for safe and effective management of acute and chronic pain at reduced NSAID doses is attractive; definitive characterization of SoluMatrix diclofenac safety requires confirmation by long-term studies.

Advances in NSAID development: evolution of diclofenac products using pharmaceutical technology

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) of the phenylacetic acid class with anti-inflammatory, analgesic, and antipyretic properties. Contrary to the action of many traditional NSAIDs, diclofenac inhibits cyclooxygenase (COX)-2 enzyme with greater potency than it does COX-1. Similar to other NSAIDs, diclofenac is associated with serious dose-dependent gastrointestinal, cardiovascular, and renal adverse effects. Since its introduction in 1973, a number of different diclofenac-containing drug products have been developed with the goal of improving efficacy, tolerability, and patient convenience. Delayed- and extended-release forms of diclofenac sodium were initially developed with the goal of improving the safety profile of diclofenac and providing convenient, once-daily dosing for the treatment of patients with chronic pain. New drug products consisting of diclofenac potassium salt were associated with faster absorption and rapid onset of pain relief. These include diclofenac potassium immediate-release tablets, diclofenac potassium liquid-filled soft gel capsules, and diclofenac potassium powder for oral solution. The advent of topical formulations of diclofenac enabled local treatment of pain and inflammation while minimizing systemic absorption of diclofenac. SoluMatrix diclofenac, consisting of submicron particles of diclofenac free acid and a proprietary combination of excipients, was developed to provide analgesic efficacy at reduced doses associated with lower systemic absorption. This review illustrates how pharmaceutical technology has been used to modify the pharmacokinetic properties of diclofenac, leading to the creation of novel drug products with improved clinical utility.

Lower gastrointestinal bleeding associated with diclofenac topical patch in a patient with colonic mass and on antiplatelet therapy for atrial fibrillation

Topical formulations of diclofenac, a nonsteroidal anti-inflammatory drug commonly prescribed to treat musculoskeletal complaints such as osteoarthritis, low back pain, and myofascial pain, are available in the form of a solution, gel, and patch. The topical application of diclofenac results in substantially lower systemic exposure to diclofenac compared with oral diclofenac, resulting in a more favorable side effect profile. To the authors' knowledge, this is the first case report of a lower gastrointestinal bleed associated with diclofenac topical patch use in a 77 yr-old-woman with a history of colonic mass and atrial fibrillation on antiplatelet therapy.

Comprehensive review on additives of topical dosage forms for drug delivery

Skin is the largest organ of the human body and plays the most important role in protecting against pathogen and foreign matter. Three important modes such as topical, regional and transdermal are widely used for delivery of various dosage forms. Among these modes, the topical dosage forms are preferred because it provides local therapeutic activity when applied to the skin or mucous membranes. Additives or pharmaceutical excipients (non-drug component of dosage form) are used as inactive ingredients in dosage form or tools for structuring dosage forms. The main use of topical dosage form additives are controling the extent of absorption, maintaining the viscosity, improving the stability as well as organoleptic property and increasing the bulk of the formulation. The overall goal of this article is to provide the clinician with information related to the topical dosage form additives and their current major applications against various diseases.

Evolving guidelines in the use of topical nonsteroidal anti-inflammatory drugs in the treatment of osteoarthritis

Background

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a standard treatment for osteoarthritis (OA), but the use of oral NSAIDs has been linked to an elevated risk for cardiovascular and gastrointestinal adverse events and renal toxicity. Topical NSAIDs are thought to afford efficacy that is comparable to oral formulations while reducing widespread systemic drug exposure, which may provide a benefit in terms of safety and tolerability. As a result, European treatment guidelines have, for many years, recommended the use of topical NSAIDs as a safe and effective treatment option for OA. Following the recent approval of several topical NSAID formulations by the US Food and Drug Administration, US treatment guidelines are increasingly recommending the use of topical NSAIDs as an alternative therapy and, in some cases, as a first-line option for OA. This commentary summarizes OA treatment guidelines that are currently available and discusses their potential evolution with regard to the increased inclusion of topical NSAIDs.

Effects of topical diclofenac plus heparin (DHEP+H plaster) on somatic pain sensitivity in healthy subjects with a latent algogenic condition of the lower limb

OBJECTIVE

To evaluate whether a diclofenac epolamine + heparin topical (plaster) is more effective than diclofenac plaster alone in reducing deep somatic hyperalgesia in subjects without spontaneous pain and whether the effect is linked to or independent of the anti-edematous action of heparin.

DESIGN

Prospective, double-blind, randomized and controlled, four-arm parallel design trial.

SUBJECTS

One hundred and four patients (84 women, 20 men, mean age 42.2 ± 13.3 years), with deep somatic hyperalgesia in one thigh, randomly assigned to one of 4 groups of 26 each.

INTERVENTION

Each group underwent one of the following plaster treatments on one thigh: diclofenac+heparin; diclofenac; heparin; placebo, for 7 days, renewing the plaster every 24 hours.

OUTCOME MEASURES

Before treatment (day 1), at day 4 and day 8, assessment of (a) pressure and electrical pain thresholds of vastus lateralis and overlying subcutis and skin; and (b) structure/thickness of subcutis and muscle with ultrasounds at the same level.

RESULTS

During treatment, in placebo and heparin, no significant threshold changes, except subcutis thresholds which increased slightly (P < 0.02); in diclofenac and diclofenac+heparin, significant increase in all thresholds (0.0001 < P < 0.04). Electrical muscle pain thresholds increased significantly more in diclofenac+heparin than in diclofenac, heparin, and placebo (0.0001 < P < 0.04). In all groups: no edema and thickness changes at ultrasounds in muscle and subcutis.

CONCLUSIONS

Topical diclofenac+heparin is significantly more effective than diclofenac alone in reducing muscle hyperalgesia in subjects without spontaneous pain, independently of the anti-edematous action of heparin. The results provide a rationale for the use of diclofenac+heparin also in algogenic conditions without evident signs of injury/edema/hematoma.

Diclofenac epolamine medicated plaster in the treatment of minor soft tissue injuries: a multicenter randomized controlled trial

OBJECTIVE

To investigate the efficacy and safety of a topical plaster containing diclofenac epolamine (DHEP) 1.3% in the treatment of patients with acute minor soft tissue injuries in China.

RESEARCH DESIGN AND METHODS

This prospective, randomized, double blind, placebo-controlled study had balanced random assignment to DHEP medicated plaster and placebo plaster. A total of 384 patients, aged 18-74 years, with minor soft tissue injury occurring within 72 hours of study entry were enrolled and randomized. Plasters were applied twice daily for seven consecutive days. Outcomes were assessed in three visits over 7 days, in addition to patients' daily self-assessment and an adverse events follow-up visit on day 21.

MAIN OUTCOME MEASURES

The primary efficacy endpoint was the mean change from baseline in pain on movement on a 100 mm Visual Analogue Scale (VAS) after 7 days of treatment. Secondary efficacy endpoints included pain on movement day-by-day evaluation, summed pain intensity difference, overall treatment efficacy, rescue medication consumption, and treatment tolerability.

RESULTS

Reduction in pain on movement after 7 days of treatment, the primary efficacy endpoint, was statistically significantly greater in the DHEP plaster group than with placebo (reduction in VAS pain scores -53.78 ± 16.96 vs -37.02 ± 18.30 for DHEP vs placebo, p < 0.0001). The greater analgesic effect of DHEP plaster was evident by day 1 and increased progressively throughout the treatment period. Global pain relief and overall treatment efficacy were significantly better with DHEP. Both DHEP and placebo plaster were well tolerated with few adverse events, mostly application site reactions.

CONCLUSIONS

A medicated plaster containing DHEP applied to the affected site in Chinese patients with minor soft tissue injury, such as sprains, strains and contusions, was significantly more effective than placebo at reducing pain scores. Onset of action was rapid and the DHEP plaster was safe and well tolerated. The main limitation was the use of a subjective, though validated, self-reported VAS to assess the primary endpoint.

The comparative effects of transdermal and intramuscular diclofenac on postlaparoscopic surgery pain

PURPOSE

Postlaparoscopic surgery pain management can reduce the discharge and recovery time. Thus conventional nonsteroidal anti-inflammatory drugs and opioids have been used for this purpose. The aim of this trial was to compare the analgesic and opioid-sparing efficacy of diclofenac sodium intramuscular (IM) with diclofenac transdermal patch in the management of postlaparoscopy pain.

METHODS

Patients were randomized to receive IM diclofenac 75 mg (n=30) 15 minutes before anesthesia or transdermal diclofenac (n=30) 3 hours before laparoscopic surgery. Transdermal or IM diclofenac were reapplied 12 hours later. All patients were administered tramadol intravenously before surgery. Postoperative pain management was maintained with tramadol using a patient-controlled analgesia device. Postoperative visual analogue pain scores (VAS, 0 to 10 cm) and adverse reactions were recorded over a 24-hour period. If VAS values were >4, 25 mg tramadol was given intravenously as a rescue analgesic.

RESULTS

In both groups, VAS scores were higher in the first 4 hours. There were no significant differences in postoperative pain between the 2 groups. The postoperative tramadol consumption, and rescue analgesic needs of the patients between both groups were not statistically significant. Injection pain was observed in the IM diclofenac group, but for both groups no skin reactions were observed at the application sites of the drugs.

CONCLUSIONS

Diclofenac transdermal patch provided pain relief for postoperative laparoscopic surgery as effectively as IM diclofenac and can be used.

Skin permeability and pharmacokinetics of diclofenac epolamine administered by dermal patch in Yorkshire-Landrace pigs

Purpose

This study compared the pharmacokinetic profile, and systemic and local absorption of diclofenac, following dermal patch application and oral administration in Yorkshire-Landrace pigs.

Patients and methods

Twelve anesthetized, female, Yorkshire-Landrace pigs were randomized to receive either the dermal patch (FLECTOR^® patch, 10 × 14 cm; Alpharma Pharmaceuticals, a subsidiary of Pfizer Inc, New York, NY) or 50 mg oral diclofenac (Voltaren^®; Novartis, East Hanover, NJ). Tissue (skin area of 2 × 2 cm and underlying muscles approximately 2–3 cm in depth) and blood (10 mL) samples were collected at timed intervals up to 11.5 hours after initial patch application or oral administration. The concentrations of diclofenac in plasma, skin, and muscle samples were analyzed using validated ultra performance liquid chromatography tandem mass spectrometric methods.

Results

Peak systemic exposure of diclofenac was very low by dermal application compared with oral administration (maximum concentration [C_max] values of 3.5 vs 9640 ng/mL, respectively). Absorption of diclofenac into underlying muscles beneath the dermal patch was sustained, and followed apparently zero-order kinetics, with the skin serving as a depot with elevated concentrations of diclofenac. Concentrations of diclofenac in muscles beneath the patch application site were similar to corresponding tissues after oral administration (C_max values of 879 and 1160 ng/mL, respectively). In contrast to the wide tissue distribution of diclofenac after oral administration, dermal patch application resulted in high concentrations of diclofenac only on the treated skin and immediate tissue underneath the patch. Low concentrations of diclofenac were observed in the skin and muscles collected from untreated areas contralateral to the site of dermal patch application.

Conclusion

Dermal patch application resulted in low systemic absorption and high tissue penetration of diclofenac compared with oral administration.

Diclofenac Salts, VIII. Effect of the Counterions on the Permeation through Porcine Membrane from Aqueous Saturated Solutions

The following bases: monoethylamine (EtA), diethylamine (DEtA), triethylamine (TEtA), monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), pyrrolidine (Py), piperidine (Pp), morpholine (M), piperazine (Pz) and their N-2-hydroxyethyl (HE) analogs were employed to prepare 14 diclofenac salts. The salts were re-crystallized from water in order to obtain forms that are stable in the presence of water. Vertical Franz-type cells with a diffusional surface area of 9.62 cm2 were used to study the permeation of these diclofenac salts from their saturated solutions through an internal pig ear membrane. The receptor compartments of the cells contained 100 mL of phosphate buffer (pH 7.4); a saturated solution (5 mL) of each salt was placed in the donor compartment, thermostated at 37 °C. Aliquots were withdrawn at predetermined time intervals over 8 h and then immediately analyzed by HPLC. Fluxes were determined by plotting the permeated amount, normalized for the membrane surface area versus time. Permeation coefficients were obtained dividing the flux values J by the concentration of the releasing phase-that is, water solubility of each salt. Experimental results show that fluxes could be measured when diclofenac salts with aliphatic amines are released from a saturated aqueous solution. Different chemical species (acid, anion, ion pairs) contribute to permeation of the anti-inflammatory agent even though ion-pairs could be hypothesized to operate to a greater extent. Permeation coefficients were found higher when the counterion contains a ring; while hydroxy groups alone do not appear to play an important role, the ring could sustain permeation, disrupting the organized domains of the membrane.

Efficacy and tolerability of DHEP-heparin plaster in reducing pain in mild-to-moderate muscle contusions: a double-blind, randomized trial

OBJECTIVES

To investigate if the 180-mg diclofenac epolamine and heparin sodium 5600 IU medicated plaster (DHEP-heparin) is more effective for pain reduction in mild-to-moderate contusions than the reference diclofenac epolamine 180 mg plaster (DHEP).

RESEARCH DESIGN AND METHODS

This multicenter, multinational, prospective, double-blind versus reference comparator and versus placebo, controlled trial had balanced random assignment in three parallel treatment groups. The DHEP-heparin medicated plaster was compared to the DHEP medicated plaster and a placebo medicated plaster. A total of 331 outpatients, aged ≥18 and ≤65 years, with unilateral mild-to-moderate muscle contusion, pain on standardized movement of ≥50 mm, and superficial hematoma of ≤10 × 14 cm(2) completed the study. Plasters were applied each morning, for ≥20 hours daily for 14 consecutive days. Outcomes were assessed in three visits, over 14 days, plus patients' daily self-assessment.

CLINICAL TRIAL REGISTRATION

05DCz/FHp11 - Eudra CT n: 2005-003829-31

MAIN OUTCOME MEASURES

Primary efficacy endpoint was mean change from baseline in pain on movement after 3 days of treatment, compared between groups. Secondary efficacy endpoints included mean daily change from baseline in pain on movement during treatment, pain level as assessed at control visits after 7 and 14 days, time (days) to hematoma disappearance based on patients' daily evaluations, rescue medication use, and overall treatment efficacy as judged by both patients and investigators.

RESULTS

Pain progressively declined in all groups, more rapidly in DHEP-heparin recipients, compared to DHEP, and in both active treatment groups compared to placebo. Adverse events were recorded in 24 of the 355 (6.7%) exposed patients, and generally resolved without need to interrupt treatment.

CONCLUSION

The DHEP-heparin plaster is superior to the reference DHEP plaster in reducing pain associated with mild-to-moderate muscle contusion. Both active treatments were significantly more effective than placebo, and each showed a comparably favorable, placebo-like safety profile.

Diclofenac salts, part 7: are the pharmaceutical salts with aliphatic amines stable?

Eight cyclic aliphatic amines, pyrrolidine (Py), piperidine (Pp), morpholine (M), piperazine (Pz), and the N-hydroxyethyl (HE) analogues, were employed to prepare a salt with acidic diclofenac (D). These salts were examined by thermal [differential scanning calorimetry (DSC), thermogravimetric analysis, and hot-stage microscopy (HSM)] and spectroscopic [Fourier transform infrared (FTIR), Raman, (1) H NMR, and ultraviolet] analysis. The results show the thermal instability of these salts: the thermal dissociation leaves the starting acidic D, evidenced by the FTIR and Raman spectra inside the molten mass of the salts with M and HEM. The nature of the salt with Pz (1:1 or 1:2) and HEPy (anhydrous or hydrate polymorph), but not for the salt with HEPz and Py, depends on the polarity of the solvent used for the preparation of the salt. Incomplete dehydration of the hydrate Py and Pz salts progressively modifies the thermogram profiles and originates false information. Melting of the salts with Pp, M, and HEM could be demonstrated by HSM, but not with DSC. The difficulty of providing a description of these salts in a simple way originates doubts on the utility of a wide application of aliphatic amines to prepare pharmaceutical salts with D, whose solubility in water does not significantly differ from that of the common sodium D.

Therapeutic efficacy and tolerability of the topical treatment of inflammatory conditions of the oral cavity with a mouthwash containing diclofenac epolamine: a randomized, investigator-blind, parallel-group, controlled, phase III study

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs), including diclofenac, are the mainstay of analgesic and anti-inflammatory treatment in dentistry. Diclofenac epolamine [diclofenac N-(2-hydroxyethyl)pyrrolidine; DHEP] is a diclofenac salt with greater water solubility and better cutaneous absorption properties than other commonly used forms of the drug. IBSA has recently developed a mouthwash formulation of DHEP for the topical treatment of inflammatory conditions of the oral cavity.

OBJECTIVE

The aim of this study was to compare the efficacy and tolerability of DHEP mouthwash (Osmal®) with that of a reference product (commercially available diclofenac mouthwash).

METHODS

This was a randomized, investigator-blind, parallel-group, controlled, phase III study that enrolled 80 patients with conditions affecting the oral cavity, characterized by an inflammatory component, and eligible for analgesic and anti-inflammatory treatment. Patients were randomized 1:1 to DHEP mouthwash (0.103% DHEP in aqueous solution) or to diclofenac mouthwash (0.074% free diclofenac in aqueous solution). The treatment regimen was the same in both groups: 1-minute rinse with 15 mL of mouthwash, twice daily for 7 days. Visits were scheduled at study inclusion (D0), and 3 days (D3) and 7 days (D7) after treatment initiation. During each visit assessments were made of pain severity (using a 5-point semi-quantitative scale and a 100-mm visual analogue scale [VAS]) and inflammatory signs (using a 5-point scale). The primary study endpoint was the change in pain severity scores from D0 to D3 and D7. Secondary endpoints included effects of treatment on inflammation score, quality of sleep, compliance with treatment and the safety and tolerability of treatment.

RESULTS

The two treatment arms were homogeneous in terms of patient characteristics. The most prevalent oral condition was gingivitis. Overall both topical treatments were effective in alleviating pain and inflammation, as evidenced by decreases in pain and inflammation scores within 3 days after treatment initiation. Notably, a significantly greater proportion of patients treated with DHEP were free of pain and inflammatory symptoms at D3 compared with those treated with the diclofenac mouthwash (40% vs 20% of patients; p < 0.05). Also, DHEP was associated with more marked, but not statistically significant, decreases in VAS pain scores versus baseline after 3 days' treatment. Compliance with both treatments was good and both mouthwashes were well tolerated.

CONCLUSION

DHEP mouthwash was at least as effective as diclofenac mouthwash at alleviating pain and inflammation symptoms and is well tolerated in patients with painful inflammatory conditions of the oral cavity. The potential of DHEP mouthwash deserves to be investigated in a larger patient population.

Pooled analysis of clinical trial data evaluating the safety and effectiveness of diclofenac epolamine topical patch 1.3% for the treatment of acute ankle sprain

This pooled analysis assessed the efficacy and safety of the diclofenac epolamine topical patch 1.3% (DETP) for the treatment of acute mild-to-moderate ankle sprain. Data from 2 randomized, double-blind, placebo-controlled studies enrolling 274 male and female patients aged 18 to 65 years with acute ankle sprain were pooled and evaluated. The primary end point was pain reduction on movement assessed using a 100 mm visual analog scale (VAS). Safety and tolerability were also assessed. Beginning approximately 3 hours after initial treatment, DETP-treated patients experienced statistically significant and sustained lower mean VAS scores in pain intensity on movement (mean ± SD, 54.1 ± 20.0 mm versus 60.3 ± 16.8 mm) compared with placebo-treated patients, representing a 20% versus 13% reduction in VA S pain scores from baseline (P = 0.012). This statistically significant difference in mean VAS score was maintained through day 7 (9.4 ± 14.4 mm versus 18.4 ± 18.2 mm, P < 0.0001). The DETP and placebo patches were well tolerated. These results further confirm the efficacy and safety of DETP for the treatment of acute pain from ankle sprains.

Recent developments in the treatment of osteoarthritis with NSAIDs

OBJECTIVE

To conduct a systematic review of evidence supporting the efficacy and safety profiles of nonsteroidal anti-inflammatory drugs (NSAIDs) introduced in the last decade for the treatment of patients with osteoarthritis (OA), including their analgesic effects, ability to improve function, and adverse event profiles relative to current standards of care.

RESEARCH DESIGN AND METHODS

Systematic search of the literature for NSAIDs approved by the FDA (2000-2010).

RESULTS

One new orally-administered NSAID molecule (meloxicam), two orally-administered NSAID formulations (naproxen plus lansoprazole; oxycodone/ibuprofen), and three topical NSAID formulations (diclofenac patch, gel, and solution) were approved by the FDA (2000-2010). A systematic literature review found evidence to support efficacy in treating patients with OA for all agents except oxycodone/ibuprofen, which has not been studied in this patient population, although ibuprofen and immediate-release oxycodone have been studied individually for OA pain. Evidence quality was inconsistent, with several agents lacking long-term, controlled trials against active comparators, and functional end points inconsistently met. Although low-dose meloxicam and naproxen plus lansoprazole offer a reduced risk of adverse gastrointestinal (GI) events, cardiovascular and renal risks remain similar to traditional oral NSAID therapy. Further, only lower doses of meloxicam appear to carry a reduced risk of GI events. Diclofenac patch, gel, and solution preparations offer the potential for reduced GI, cardiovascular, and renal adverse events. The level of evidence available to support the efficacy and safety of these agents for long-term treatment of patients with OA differs, with some having only short-term trials, while others have longer-duration trials with active comparators.

CONCLUSIONS

By expanding the treatment armamentarium, newly-approved NSAID agents may improve the ability of clinicians to tailor analgesic therapy for their diverse patient populations and to achieve realistic functional improvements. The comparisons in this article were limited to drugs that received approval after 2000 and should be considered accordingly.

Topical preparations for pain relief: efficacy and patient adherence

There has been an increasing focus on development of new routes of drug administration to provide tailored treatments for patients, without decreasing efficacy of analgesia, in proportion to the progression of the knowledge of pain mechanisms. While acute pain acts as an alarm, chronic pain is a syndrome requiring meticulous selection of analgesic drugs of high bioavailability for long-term use. Such criteria are challenges that topical medications aim to overcome, allowing progressive delivery of active component, maintaining stable plasma levels, with a good safety profile. This review presents recent findings regarding topical formulations of the most widely used drugs for pain treatment, such as nonsteroidal anti-inflammatory agents, anesthetics, and capsaicin, and the role of physical agents as delivery enhancers (phonophoresis and iontophoresis). Although the number of topical agents is limited for use in peripheral conditions, increasing evidence supports the efficacy of these preparations in blocking nociceptive and neuropathic pain. Patient adherence to medical treatment is also a challenge, especially in chronic painful conditions. It is known that reduction of treatment complexity and pill burden are good strategies to increase patient compliance, as discussed here. However, the role of topical presentations, when compared to traditional routes, has not yet been fully explored and thus remains unclear.

Review of the efficacy and tolerability of the diclofenac epolamine topical patch 1.3% in patients with acute pain due to soft tissue injuries

BACKGROUND

The diclofenac epolamine topical patch 1.3% (DETP) was approved by the US Food and Drug Administration in January 2007 for the treatment of soft tissue injuries such as strains, sprains, and contusions, although it has been available for many years in >40 countries worldwide.

OBJECTIVE

The aim of this study was to review the efficacy and tolerability of the DETP in relieving acute pain caused by soft tissue injuries.

METHODS

The MEDLINE, Derwent Drug File, BIOSIS, and EMBASE databases were searched for literature published between 1984 and October 30, 2009, in any language, using the terms diclofenac epolamine patch, diclofenac hydroxyethylpyrrolidine patch, and FLECTOR Patch. Clinical studies of the efficacy and/or tolerability of the DETP in patients with acute pain due to soft tissue injuries or localized periarticular disorders were included. Efficacy studies that enrolled patients with other medical conditions were excluded, except for reports that focused on tolerability, which were included to supplement tolerability data. The bibliographies of included studies were reviewed manually for relevant articles based on inclusion and exclusion criteria, and the manufacturer was contacted for additional relevant postmarketing surveillance information and presentations from scientific meetings.

RESULTS

The search identified 6 placebo-controlled clinical studies, 1 active-comparator-controlled clinical study, and 1 open-label comparator clinical study of the efficacy and tolerability of the DETP in patients with soft tissue injuries. Three studies reported on tolerability. Primary analyses among the 8 studies reported DETP-associated reductions in spontaneous pain from baseline, assessed using a visual analog scale, ranging from 26% to 88% on day 7 and 56% to 61% on day 14. The use of the DETP was associated with significantly greater reductions in pain scores compared with a placebo patch (2 studies) on day 7 (88% vs 74%; P = 0.001) and day 14 (56.5% vs 46.8%; P = 0.001) and compared with diclofenac diethylammonium topical gel (1 study) on day 14 (60.8% vs 40.8%; P < 0.001). With the use of the DETP, median time to pain resolution was 3 days less than with placebo (8.8 vs 12.4 days; P = 0.009). The prevalences of adverse events across the 11 studies were low (3.1%-14.0%) and not significantly different from those with placebo (5.8%-16.0%). The most commonly reported adverse events were cutaneous application-site reactions (pruritus, rash, and dermatitis) and gastrointestinal symptoms (nausea).

CONCLUSION

Based on data from clinical studies and postmarketing experience, the DETP was associated with significant pain relief in patients with soft tissue injuries, with good tolerability.

Topical diclofenac epolamine patch 1.3% for treatment of acute pain caused by soft tissue injury

Acute pain caused by musculoskeletal disorders is very common and has a significant negative impact on quality-of-life and societal costs. Many types of acute pain have been managed with traditional oral non-steroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase-2 inhibitors (coxibs). Data from prospective, randomised controlled clinical trials and postmarketing surveillance indicate that use of oral traditional NSAIDs and coxibs is associated with an elevated risk of developing gastrointestinal, renovascular and/or cardiovascular adverse events (AEs). Increasing awareness of the AEs associated with NSAID therapy, including coxibs, has led many physicians and patients to reconsider use of these drugs and look for alternative treatment options. Treatment with NSAIDs via the topical route of administration has been shown to provide clinically effective analgesia at the site of application while minimising systemic absorption. The anti-inflammatory and analgesic potency of the traditional oral NSAID diclofenac, along with its physicochemical properties, makes it well suited for topical delivery. Several topical formulations of diclofenac have been developed. A topical patch containing diclofenac epolamine 1.3% (DETP, FLECTOR(®) Patch), approved for use in Europe in 1993, has recently been approved for use in the United States and is indicated for the treatment of acute pain caused by minor strains, sprains and contusions. In this article, we review the available clinical trial data for this product in the treatment of pain caused by soft tissue injury.

A plaster containing DHEP and heparin for mild to moderate contusions and sprains with haematoma: a double-blind randomized study

OBJECTIVE

This prospective, randomized, double-blind, three-arm study was performed to investigate the efficacy of a medicated plaster containing the combination of diclofenac epolamine (DHEP) 180 mg and heparin 5600 IU in the treatment of unilateral blunt soft tissue injuries involving the upper or lower limb, complicated by severe local haematoma.

RESEARCH DESIGN AND METHODS

Patients with mild-to-moderate injuries complicated by local haematoma (< or =140 cm(2)) were included and randomly treated once daily with plasters containing DHEP/heparin, DHEP only, or placebo. Plasters were applied for at least 12 hours daily for 10 consecutive days.

MAIN OUTCOME MEASURES

The time to complete haematoma dissolution was the primary efficacy endpoint; secondary endpoints were spontaneous pain reduction, pain on movement, muscle swelling and use of rescue analgesia.

RESULTS

A total of 185 patients (90 males and 95 females, aged 18-80 years) were evaluated for efficacy. Baseline clinical and demographic characteristics were similar across the treatment groups. The time to complete haematoma dissolution was significantly shorter with the DHEP/heparin plaster compared with both the DHEP and placebo plasters (p < 0.05). Patients in the DHEP/heparin group had a 60% probability of achieving complete haematoma dissolution within the 10-day treatment period compared with patients receiving either DHEP or placebo plasters. Patient-rated reductions in pain on movement were significantly (p < 0.05) greater in the two active treatment groups compared with placebo. Overall, the DHEP/heparin, DHEP and placebo plasters were well-tolerated. While a reliance on patient self-reporting had the potential to limit the usefulness of some data obtained in this study, the investigators accounted for this accordingly.

CONCLUSIONS

The plaster formulation combining DHEP and heparin relieves pain and induces faster dissolution of superficial haematomas, and may therefore contribute to a more rapid and complete recovery.

Diclofenac: an update on its mechanism of action and safety profile

BACKGROUND

Diclofenac is a proven, commonly prescribed nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-inflammatory, and antipyretic properties, and has been shown to be effective in treating a variety of acute and chronic pain and inflammatory conditions. As with all NSAIDs, diclofenac exerts its action via inhibition of prostaglandin synthesis by inhibiting cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) with relative equipotency. However, extensive research shows the pharmacologic activity of diclofenac goes beyond COX inhibition, and includes multimodal and, in some instances, novel mechanisms of action (MOA).

DATA SOURCES

Literature retrieval was performed through PubMed/MEDLINE (through May 2009) using combinations of the terms diclofenac, NSAID, mechanism of action, COX-1, COX-2, and pharmacology. Reference citations resulting from publications identified in the literature search were reviewed when appropriate.

METHODS

This article reviews the established, putative, and emerging MOAs of diclofenac; compares the drug's pharmacologic and pharmacodynamic properties with other NSAIDs to delineate its potentially unique qualities; hypothesizes why it has been chosen for further recent formulation enhancement; and evaluates the potential effect of its MOA characteristics on safety.

DISCUSSION

Research suggests diclofenac can inhibit the thromboxane-prostanoid receptor, affect arachidonic acid release and uptake, inhibit lipoxygenase enzymes, and activate the nitric oxide-cGMP antinociceptive pathway. Other novel MOAs may include the inhibition of substrate P, inhibition of peroxisome proliferator activated receptor gamma (PPARgamma), blockage of acid-sensing ion channels, alteration of interleukin-6 production, and inhibition of N-methyl-D-aspartate (NMDA) receptor hyperalgesia. The review was not designed to compare MOAs of diclofenac with other NSAIDs. Additionally, as the highlighted putative and emerging MOAs do not have clinical data to demonstrate that these models are correct, further research is necessary to ascertain if the proposed pathways will translate into clinical benefits. The diversity in diclofenac's MOA may suggest the potential for a relatively more favorable profile compared with other NSAIDs.

A Review of Topical Diclofenac Use in Musculoskeletal Disease

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed medications for the treatment of musculoskeletal disorders. Osteoarthritis is the most common form of arthritis in humans and its prevalence rises with age. Oral NSAIDs have potential associated toxicities that must be monitored for and can limit the use of these drugs in certain populations including people of older age. Topical NSAIDs are now being recognized as an option for the treatment strategy of osteoarthritis. We review the efficacy and safety of one of the most common topical NSAIDS, topical diclofenac, for the treatment of osteoarthritis.

Adverse effects of topical nonsteroidal antiinflammatory drugs in older adults with osteoarthritis: a systematic literature review

OBJECTIVE

To systematically review the literature on reported adverse effects (AE) associated with use of topical nonsteroidal antiinflammatory drugs (NSAID) in older adults with osteoarthritis (OA).

METHODS

A systematic search of Medline (1950 to November 2009), Scopus, Embase, Web of Science, Cochrane databases, Dissertation and American College of Rheumatology meeting abstracts was performed to identify original randomized controlled trials, case reports, observational studies, editorials, or dissertations reporting AE from topical NSAID in older adults with OA. Information was sought on study and participant characteristics, detailed recording of application site, and systemic AE as well as withdrawals due to AE.

RESULTS

The initial search yielded 953 articles of which 19 met eligibility criteria. Subjects receiving topical NSAID reported up to 39.3% application site AE, and up to 17.5% systemic AE. Five cases of warfarin potentiation with topical agents were reported, 1 resulting in gastrointestinal bleeding. In formal trials, the withdrawal rate from AE ranged from 0 to 21% in the topical agents, 0 to 25% in the oral NSAID, and 0 to 16% in the placebo group.

CONCLUSION

Although topical NSAID are safer than oral NSAID (fewer severe gastrointestinal AE), a substantial proportion of older adults report systemic AE with topical agents. The withdrawal rate due to AE with topical agents is comparable to that of oral NSAID. Given the safety profile and withdrawal rates described in this study, further data are needed to determine the incremental benefits of topical NSAID compared to other treatment modalities in older adults with OA.