Diclofenac potassium 12.5mg tablets for mild to moderate pain and fever: a review of its pharmacology, clinical efficacy and safety

Toxicity of diclofenac sodium salt after two weeks of daily intramuscular administration in cynomolgus monkeys

Diclofenac sodium salt (DSS) has been extensively studied in pharmacological research to better understand its pain relief and inflammation-reducing properties. However, it is crucial to evaluate the safety profile of this non-steroidal anti-inflammatory drug, particularly in nonhuman primates (NHPs), such as cynomolgus monkeys. Understanding the potential adverse effects and toxicity of DSS in NHP is critical for determining their overall safety and use in clinical settings. Further investigation into its toxicity to NHPs would provide valuable information for developing and using this drug in medical practice. Our aim was to evaluate the toxicity of DSS administered repeatedly to cynomolgus monkeys to identify its safety profile in NHPs. The general toxicity of DSS was established using a 2-week repeated-dose toxicity test. Twenty-four cynomolgus monkeys were intramuscularly injected with 0, 0.33, 1, and 3 mg/kg of DSS each day. This study assessed the potential adverse effects and toxicity of DSS in these monkeys, providing valuable data for understanding its safety in clinical settings. The 2-week repeated-dose toxicity study of DSS revealed no treatment-related changes in body weight, food consumption, ophthalmology, or general symptoms. Furthermore, no significant changes were observed in hematological, clinical chemistry, or urinalysis data. Histopathological examination revealed decreased cellularity (lymphocytes) in both the thymus and spleen (white pulp). The sternal bone marrow had a higher cell count than usual. Furthermore, mixed cell and mononuclear cell infiltration, inflammation, myofiber degeneration, and muscle fiber necrosis were observed at the injection site (skin), but these findings were not considered adverse effects. Notably, the no observed adverse effect level of DSS was estimated to be greater than 3 mg/kg in both males and females. Therefore, this study established a non-toxic dose of DSS, laying the groundwork for further nonclinical studies to assess the safety of DSS using NHP.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-025-00281-4.

Treatment Satisfaction, Efficacy, and Tolerability of Low-Dose Diclofenac Epolamine Soft Capsules in Acute, Mild, or Moderate Musculoskeletal Pain: A Prospective Open-Label, Single-Arm Interventional Study

INTRODUCTION

The use of oral nonsteroidal anti-inflammatory drugs (NSAIDs) for acute musculoskeletal pain should be at the lowest effective dosage and for the shortest duration to minimize potential adverse effects. This study evaluated treatment satisfaction, effectiveness, and tolerability of a low-dose diclofenac epolamine 12.5-mg soft capsule formulation (DHEP 12.5-mg capsules) using patient-reported outcome measures in a real-life setting over a short period (3 days) in subjects with mild-to-moderate acute musculoskeletal pain.

METHODS

A prospective, open-label, phase IV clinical study in adult outpatients at hospital clinic departments/general practitioner's clinics at eight sites in Italy. The primary efficacy variable was the degree of satisfaction with treatment at 72 ± 7 h after initiation of treatment, assessed using the Overall Satisfaction Question of the Pain Treatment Satisfaction Scale (PTSS) and described by classic descriptive statistics. Secondary objectives were to evaluate the analgesic effect after the first administration and over time; the time to and satisfaction with the onset of pain relief, amount of and duration of pain relief; pain intensity differences over time; and safety and tolerability. The investigator's satisfaction with the treatment was also assessed. Subjects initially took 1-2 capsules of the study treatment and then one or two soft capsules every 4-6 h according to their needs. Not more than six soft capsules were to be taken in any 24-h period.

RESULTS

A total of 182 subjects (mean age, 56.2 years; 54.4% female) took ≥ 1 dose of DHEP capsule and were included in the full analysis set. The most common musculoskeletal conditions were arthralgia (39.0%) and low back pain (23.1%). All subjects completed the study, and 165/182 (90.7%, 95% CI 0.86, 0.95) were satisfied or very satisfied with the treatment at 72 ± 7 h after the first dose (primary efficacy variable). Similar percentages were recorded for treatment satisfaction concerning other efficacy parameters. The onset of the analgesic effect was rapid, with complete pain relief reached after a mean of 49.45 min. Investigators rated their overall treatment satisfaction as 92.9%. Treatment was well tolerated.

CONCLUSIONS

The low-dose (12.5 or 25 mg) oral diclofenac epolamine soft capsules formulation exerted rapid, effective, and safe analgesic activity in patients with mild-to-moderate musculoskeletal pain, with subjects' overall satisfaction with treatment more than 90%.

TRIAL REGISTRATION

EudraCT Number: 2018-004886-15 (Study 18I-Fsg08). Registered 04/09/2018.

Combination of Enzymes and Rutin to Manage Osteoarthritis Symptoms: Lessons from a Narrative Review of the Literature

Osteoarthritis is the most common joint disorder affecting over 300 million people worldwide. It typically affects the knees and the hips, and is characterized by a loss in normal joint movement, stiffness, swelling, and pain in patients. The current gold standard therapy for osteoarthritis targets pain management using nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs are associated with several potentially serious side effects, the most common being gastrointestinal perforation and bleeding. Owing to the side effects, NSAID treatment doses need to be as low as possible and should be continued for the shortest duration possible, which is problematic in a chronic condition like osteoarthritis, which requires long-term management. Numerous clinical trials have examined oral enzyme combinations as a potential new approach in managing pain in patients with osteoarthritis. Oral enzyme combinations containing bromelain in combination with trypsin, both proteolytic enzymes, as well as the plant flavonoid rutin, may be an effective alternative to typical NSAIDs. The aim of this narrative review is to summarize and discuss the evidence on the efficacy of oral enzyme combinations compared to the gold standard (NSAID) in the management of osteoarthritis symptoms. Nine randomized controlled trials identified in this review assessed the efficacy and safety of the oral enzyme combination containing bromelain, trypsin, and rutin in patients with osteoarthritis. Most of the studies assessed the impact of the oral enzyme combination on the improvement of the Lequesne Algofunctional index score, treatment-related pain intensity alterations and adverse events compared to patients receiving NSAIDs. Although largely small scale, the study outcomes suggest that this combination is as effective as NSAIDs in the management of osteoarthritis, without the adverse events associated with NSAID use. INFOGRAPHIC.

Coronary Risks Associated with Diclofenac and Other NSAIDs: An Update

The risk of coronary events with non-steroidal anti-inflammatory drugs has been the subject of much debate since the original trial of rofecoxib raised the issue. Since then, over almost 20 years, such risks have been shown in clinical trials of long-term high-dose users, and in observational studies comparing users with non-users. The roles of cyclooxygenase (COX)-2/COX-1 selectivity and COX-2 inhibitory potency have been proposed to explain this increased risk of myocardial infarction (MI). Among NSAIDs, diclofenac appeared to be associated with a relatively higher risk of MI, similar to that of rofecoxib, compatible with the drug's high COX-2 inhibitory potency. Recent studies have resulted in further information being available. A study in the Danish healthcare system using active comparators found a slightly increased risk of MI in healthy persons. However, risk decreased with increasing baseline cardiovascular risk, to the point that in patients at high cardiovascular risk, there was no additional risk associated with diclofenac compared with paracetamol or other NSAIDs. The other major study, from the SOS project, studied several million persons in four countries in Europe, comparing the use of many NSAIDs with non-use. That study found a slightly increased risk with diclofenac compared with non-use, but this was not different from other NSAIDs. Comparing risks with selectivity or potency found no effect of either. These studies refute the main hypotheses to explain the coronary risk of NSAIDs. Finding risk in healthy low-risk patients only questions the reality of a link between the use of the drugs and the occurrence of MI in these conditions. Biases or confounding may be the major reason for small increases in cardiovascular risks in healthy users of NSAIDs in real life.

An investigation of the views and practices of Australian community pharmacists on pain and fever management and clinical guidelines

Background:

Fever and pain are common conditions in the Australian healthcare setting. Whilst clinical guidelines provide important therapeutic recommendations, evidence suggests they are not always followed. Given that community pharmacy is one of the most frequently accessed primary healthcare services, it is important to understand the views and practices of community pharmacists in pain and fever.

Objectives:

To investigate the views and practices of Australian community pharmacists in pain and fever management, and their views on relevant clinical guidelines.

Methods:

A cross-sectional study of community pharmacists in Australia was conducted using a customised, anonymous, self-administered, online questionnaire between March and May 2018. To capture a broad range of demographics, pharmacists were recruited via local industry contacts and the Pharmaceutical Society newsletter, with further recruitment through snowball sampling. The main outcomes measured were pharmacists’ views, practices and treatment recommendation of choice in pain and fever management, as well as views on clinical guidelines and training.

Results:

A total of 113 pharmacists completed the survey. In general, paracetamol (72%) was preferred as a recommendation over ibuprofen, and was the drug of choice for most mild to moderate pain and fever scenarios. Majority of pharmacists reported good knowledge of pain and fever management, however, only approximately half reported recent pain management training. Greater than 87% of pharmacists believe that clinical guidelines are useful in fever management, and 79% of pharmacists believe that following clinical guidelines is important in pain management.

Conclusions:

While most pharmacists recognise the importance of guidelines and demonstrated good pain and fever management, results suggests opportunities to promote additional education, upskilling, and research in this space to further optimise pain and fever management in the community.

Pharmacoepidemiology of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are reversible inhibitors of cyclo-oxygenase (COX), mainly used for the symptomatic relief of pain, whether traumatic, infectious, episodic or rheumatologic. Use for the long-term relief of inflammation is waning with the emergence of specific biotherapies. Their effects are related to potency, dosage, and pharmacokinetic or galenic considerations. Adverse reactions are mostly related to COX inhibition, and to the relative COX1 and COX2 inhibition. Over the years have resulted in the withdrawal of some NSAIDs. The most common adverse reactions are: gastrointestinal (COX1) which have declined over time with the emergence of more COX1 sparing drugs and gastroprotection; renal, with an impact on renal function and sodium extraction that is associated with hypertension, heart failure exacerbation, and stress-related renal failure; allergic skin reactions; increased transaminases and acute liver injury which may be idiosyncratic or immunoallergic; increased risk of acute coronary syndromes, initially associated with high-dose long-term use of COX2 specific inhibitors in controlled clinical trials, though more recently there have been indications from poorly controlled observational studies that they could occur with most NSAIDs. Event rates in patients with no overt coronary heart disease are vanishingly low, and the real magnitude of the issue in the treatment of common pain is still unknown. Considering their purely symptomatic effects, they should be used at the lowest possible dose for the shortest possible time, based on the symptomatic relief of pain or fever.

Submucosal Diclofenac for Acute Postoperative Pain in Third Molar Surgery: A Randomized, Controlled Clinical Trial

Diclofenac sodium is a widely used nonsteroidal anti-inflammatory drug (NSAID) for relief of inflammatory pain. A recent formulation combines this drug with hydroxypropyl-β-cyclodextrin (HPβCD) to improve its solubility and to enable subcutaneous administration. Previous studies confirmed the efficacy of this combination. This study's aim was to evaluate the efficacy, safety, and local tolerability of diclofenac HPβCD administered as a local submucosal injection prior to lower third molar surgery. We conducted a prospective, randomized, double-blind, placebo-controlled, parallel-group phase II single-center study. Seventy-five patients requiring mandibular third molar surgery were randomized into 1 of 5 groups: 5 mg/1 mL diclofenac HPβCD, 12.5 mg/1 mL diclofenac HPβCD, 25 mg/1 mL diclofenac HPβCD, 50 mg/1 mL diclofenac HPβCD, or 1 mL placebo. The respective study drug was injected into the mucosal tissue surrounding the surgical site prior to surgery following achievement of local anesthesia. The primary outcome measure was the area under the curve (AUC) of cumulative pain scores from end of surgery to 6 h postsurgery. This demonstrated a global treatment effect between the active groups and placebo, hence confirming the study drug's efficacy ( P = 0.0126). Secondary outcome measures included the time until onset of pain and the time until patients required rescue medication, both showing statistical significance of the study drug compared to placebo ( P < 0.0161 and P < 0.0001, respectively). The time until rescue medication ranged between 7.8 h (for 25 mg/1 mL diclofenac HPβCD) and 16 h (for 50 mg/1 mL diclofenac HPβCD). Interestingly, the 5-mg/1-mL solution appeared superior to the 12.5-mg/1-mL and 25-mg/1-mL solutions (time until rescue medication = 12.44 h). A total of 14% of patients experienced minor adverse drug reactions (ADRs), of which 2 cases demonstrated flap necrosis. These resolved without further intervention. The study results overall indicate efficacy, safety, and relative tolerability of diclofenac HPβCD used locally as a submucosal injection prior to third molar surgery (ClinicalTrials.gov NCT01706588).

Efficacy, tolerability, and safety of an oral enzyme combination vs diclofenac in osteoarthritis of the knee: results of an individual patient-level pooled reanalysis of data from six randomized controlled trials

Objective

To compare efficacy, safety, and tolerability of an oral enzyme combination (OEC) containing proteolytic enzymes and bioflavonoid vs diclofenac (DIC), a nonselective nonsteroidal anti-inflammatory drug in the treatment of osteoarthritis of the knee.

Materials and methods

This was an individual patient-level pooled reanalysis of patient-reported data from prospective, randomized, double-blind, parallel-group studies in adult patients with moderate-to-severe osteoarthritis of the knee treated for at least 3 weeks with OEC or DIC. Appropriate trials were identified with a systemic literature and database search. Data were extracted from the original case-report forms and reanalyzed by a blinded evaluation committee. The primary end point was the improvement of the Lequesne algofunctional index (LAFI) score at study end vs baseline. Secondary end points addressed LAFI response rates, treatment-related pain-intensity changes, adverse events, and laboratory parameters.

Results

Six trials were identified that enrolled in total 774 patients, of whom 759 had post-baseline data for safety analysis, 697 (n=348/349 with OEC/DIC) for intent to treat, 524 for per protocol efficacy analysis, and 500 for laboratory evaluation. LAFI scores – the primary efficacy end point – decreased comparably with both treatments and improved with both treatments significantly vs baseline (OEC 12.6±2.4 to 9.1±3.9, DIC 12.7±2.4 to 9.1±4.2, effect size 0.9/0.88; P<0.001 for each). In parallel, movement-related 11-point numeric rating-scale pain intensity improved significantly (P<0.001) and comparably with both treatments from baseline (6.4±1.9/6.6±1.8) to study end (3.8±2.7/3.9±2.5). Overall, 55/81 OEC/DIC patients of the safety-analysis population (14.7%/21.1%, P=0.022) reported 90/133 treatment-emergent adverse events, followed by premature treatment discontinuations in 22/39 patients (5.9%/10.2%, P=0.030). Changes in laboratory parameters were significantly less with OEC vs DIC: on average 18.8% vs 86.3% of patients presented a decrease with respect to hemoglobin, hematocrit, or erythrocyte count (P<0.001), and 28.2% vs 72.6% showed an increase in AST, ALT, or GGT (P<0.001).

Conclusion

When compared with DIC, OEC showed comparable efficacy and a superior tolerability/safety profile associated with a significantly lower risk of treatment-emergent adverse events, related study discontinuations, and changes in laboratory parameters.

Diclofenac Potassium Transdermal Patches Using Natural Rubber Latex Biomembranes as Carrier

The aim of this study was to design a compound transdermal patch containing diclofenac potassium (Dic-K) using natural rubber latex (NRL) biomembrane. The NRL from Hevea brasiliensis is easily manipulated and low cost and presents high mechanical resistance. It is a biocompatible material which can stimulate natural angiogenesis and is capable of adhering cells on its surface. Recent researches have used the NRL for Transdermal Drug Delivery Systems (TDDSs). Dic-K is used for the treatment of rheumatoid arthritis and osteoarthritis and pain relief for postoperative and posttraumatic cases, as well as inflammation and edema. Results showed that the biomembrane can release Dic-K for up to 216 hours. The kinetics of the Dic-K release could be fitted with double exponential function. X-ray diffraction and Fourier Transform Infrared (FTIR) spectroscopy show some interaction by hydrogen bound. The results indicated the potential of the compound patch.

Relative bioavailability of diclofenac potassium from softgel capsule versus powder for oral solution and immediate-release tablet formulation

The oral bioavailability of diclofenac potassium 50 mg administered as a soft gelatin capsule (softgel capsule), powder for oral solution (oral solution), and tablet was evaluated in a randomized, open-label, 3-period, 6-sequence crossover study in healthy adults. Plasma diclofenac concentrations were measured using a validated liquid chromatography-mass spectrometry/mass spectrometry method, and pharmacokinetic analysis was performed by noncompartmental methods. The median time to achieve peak plasma concentrations of diclofenac was 0.5, 0.25, and 0.75 hours with the softgel capsule, oral solution, and tablet formulations, respectively. The geometric mean ratio and associated 90%CI for AUCinf, and Cmax of the softgel capsule formulation relative to the oral solution formulation were 0.97 (0.95-1.00) and 0.85 (0.76-0.95), respectively. The geometric mean ratio and associated 90%CI for AUCinf and Cmax of the softgel capsule formulation relative to the tablet formulation were 1.04 (1.00-1.08) and 1.67 (1.43-1.96), respectively. In conclusion, the exposure (AUC) of diclofenac with the new diclofenac potassium softgel capsule formulation was comparable to that of the existing oral solution and tablet formulations. The peak plasma concentration of diclofenac from the new softgel capsule was 67% higher than the existing tablet formulation, whereas it was 15% lower in comparison with the oral solution formulation.

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.

Assessment of rescue opioid use in patients with post-bunionectomy pain treated with diclofenac potassium liquid-filled capsules

When used in multimodal analgesia for acute pain, nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the requirement for opioids during the perioperative period. To provide more insight into pain treatment during the outpatient period, we examined the use of opioid rescue medication (RM) and described the relationship between pain intensity and RM use in patients with acute pain after bunionectomy. Patients received placebo or 25 mg of a liquid-filled capsule version of the NSAID diclofenac potassium (DPLFC; n=188 patients/group) every 6 hours during the 48-hour inpatient period through the end of outpatient dosing on day 4. Opioid RM (hydrocodone/acetaminophen tablets, 5 mg/500 mg) was available as needed, but taken at least 1 hour post-study medication. Fewer patients taking DPLFC versus placebo requested opioid RM during the inpatient period (4.8%-44.7% versus 25.0%-90.4%) and also during the outpatient period (3.7%-16.0% versus 13.1%-46.4%). Moderate or severe pain after surgery (P=0.0307 and P=0.0002, respectively) or at second dose (P=0.0006 and P=0.0002, respectively) was predictive of RM use. Patients taking RM (placebo/DPLFC) reported more adverse events (RM 55.7%/40.6%; no RM 29.4%/26.0%). Most adverse events in the RM group were opioid-related. In summary, this study shows that DPLFC lowers the requirement for opioids, which is associated with a reduction in the occurrence of treatment side effects, while maintaining adequate analgesia for patients with moderate acute pain in both the outpatient and outpatient periods. Patients with more severe pain are more likely to use RM, but they still use fewer opioids when treated with DPLFC. This suggests that multimodal treatment using DPLFC and an opioid may offer an important clinical benefit in the treatment of acute pain, including in the home environment.

Cardiovascular events associated with the long-term use of NSAIDs: a review of randomized controlled trials and observational studies

INTRODUCTION

An increased risk of cardiovascular thrombotic events in users of NSAIDs was first demonstrated for rofecoxib. This risk seems to be related to the COX-2 inhibitory potency and has been found with most NSAIDs except naproxen. Two main hypotheses have been advanced: an imbalance between COX-1-dependent platelet production of thromboxane and partly COX-2-dependent endothelial production of prostacyclin, and a COX-2-dependent increase in blood pressure.

AREAS COVERED

Clinical trials and observational studies providing information about cardiovascular risk associated with long-term use of NSAIDs were retrieved; 14 clinical trials and 16 observational studies mentioned a follow-up of at least 6 months.

EXPERT OPINION

Results are ambiguous: long-term exposure seemed associated with an increased risk of myocardial infarction or stroke with high-dose rofecoxib, and perhaps diclofenac, but less with other NSAIDs. In other studies, little or no increase in risk was associated with exposures shorter than 30 days. Since most NSAIDs are rarely used long term, there is little information on risks associated with long-term use. The relative risks or odds ratios associated with most drugs are mostly well below 2.

Medication pain management in the elderly: unique and underutilized analgesic treatment options

BACKGROUND

By 2030, the US population of adults aged ≥65 years will increase by >80%, and these adults will account for nearly 20% of the US population. In this population, the decline of multiple physiologic processes and diseases collectively influence treatment options. Physiologic changes, drug-drug interactions resulting from polypharmacy, and drug-disease interactions combine to make elderly patients more sensitive to the adverse events (AEs) associated with medications, all of which must be considered in drug selection.

OBJECTIVE

This article focuses on select underutilized medication options for analgesia that may provide significant advantages in the elderly population above and beyond commonly prescribed conventional choices.

METHODS

We performed a complete review of the literature using the search terms pain management, elderly, opioids, NSAIDs, topical NSAIDs, levorphanol, buprenorphine transdermal, and tapentadol. Databases searched included PubMed, Google Scholar, Ovid, and Athens. Package inserts were utilized for approval dates, indications, and formulations available. We looked at reviews of agents to identify important studies for consideration that searches may have missed. Pharmacology and pharmacokinetic data were taken from randomized trials focusing in this area. Pivotal Phase III trials were utilized for discussion of clinical trial experience and to summarize efficacy and AEs. For purposes of validity, only peer-reviewed literature was included.

RESULTS

There were limited data that specifically outlined analgesic drug selection and highlighted safer alternatives for the elderly patient based on polypharmacy risks, end-organ deterioration, and/or drug choices that presented less risk. We focused on unique opioid alternatives: levorphanol, which offers several therapeutic advantages similar to methadone but without the pharmacokinetic and drug-interaction pitfalls associated with methadone; tapentadol, associated with significantly less gastrointestinal distress and constipation; and transdermal buprenorphine, an agonist/antagonist with less risk for the toxicities associated with conventional opioids and with compliance benefits. Topical NSAIDs are discussed as a viable therapeutic option. Specific attention to a more desirable tolerability profile, including avoidance of drug interactions, end-organ dysfunction, and gastrointestinal bleed with topical NSAID agents versus their oral counterparts is discussed, including the ability to achieve superior tissue levels for appropriately selected inflammatory conditions.

CONCLUSION

It is incumbent that providers consider these options as part of an analgesic armamentarium in an effort to maximize therapeutic benefit and minimize risks in the increasing elderly patient population.

Inhibition of mitochondrial complex I by various non-steroidal anti-inflammatory drugs and its protection by quercetin via a coenzyme Q-like action

Mitochondrial dysfunction plays a major role in the development of oxidative stress and cytotoxicity induced by non-steroidal anti-inflammatory drugs (NSAIDs). A major objective of the present study was to investigate whether in vitro the NSAIDs, aspirin, indomethacin, diclofenac, piroxicam and ibuprofen, which feature different chemical structures, are able to inhibit mitochondrial complex I. All NSAIDs were effective inhibitors when added both, directly to mitochondria isolated from rat duodenum epithelium (50 μM) or to Caco-2 cells (250 μM). In the former system, complex I inhibition was concentration-dependent and susceptible to competition and reversion by the addition of coenzyme Q (32.5-520 μM). Based on reports suggesting a potential gastro-protective activity of quercetin, the ability of this flavonoid to protect isolated mitochondria against NSAIDs-induced complex I inhibition was evaluated. Low micromolar concentrations of quercetin (1-20 μM) protected against such inhibition, in a concentration dependent manner. In the case of aspirin, quercetin (5 μM) increased the IC50 by 10-fold. In addition, the present study shows that quercetin (5-10 μM) can behave as a "coenzyme Q-mimetic" molecule, allowing a normal electron flow along the whole electron transporting chain (complexes I, II, III and IV). The exposed findings reveal that complex I inhibition is a common deleterious effect of NSAIDs at the mitochondrial level, and that such effect is, for all tested agents, susceptible to be prevented by quercetin. Data provided here supports the contention that the protective action of quercetin resides on its, here for first time-shown, ability to behave as a coenzyme Q-like molecule.

The pharmacokinetic parameters of a single dose of a novel nano-formulated, lower-dose oral diclofenac

INTRODUCTION

There is a clinical need for new nonsteroidal anti-inflammatory drugs (NSAIDs) and/or new formulations that, at minimum, retain the established efficacy of standard NSAIDs while minimizing their associated adverse events. This phase 1 clinical trial characterizes the pharmacokinetic (PK) profile of an investigational, proprietary, nano-formulated, lower-dose oral diclofenac (nano-formulated diclofenac) compared with oral diclofenac in healthy subjects.

METHODS

A single-center, single-dose, randomized, open-label, 5-period, 5-treatment, 10-sequence crossover study was completed in 30 healthy subjects. Subjects received either nano-formulated diclofenac 18 mg or 35 mg or diclofenac 50 mg in fed and fasting states. The maximum measured plasma concentration (Cmax), time to maximum measured concentration (Tmax), terminal elimination half-life (T1/2), and area under the concentration time curve (AUC), along with safety and tolerability, were assessed.

RESULTS

Mean (± standard deviation) Tmax for nano-formulated diclofenac 18 (0.62 ± 0.35 h) and 35 mg (0.59 ± 0.20 h) demonstrated faster absorption than diclofenac 50 mg (0.80 ± 0.50 h). The T1/2 was similar between nano-formulated diclofenac 35 mg and diclofenac 50 mg (1.85 ± 0.45 h vs 1.92 ± 0.38 h, respectively). The Cmax for nano-formulated diclofenac 35 mg and diclofenac 50 mg was comparable in fasted subjects (1347 ± 764 ng/mL vs 1316 ± 577 ng/mL, respectively), but lower in fed subjects (524 ± 222 ng/mL vs 951 ± 391 ng/mL, respectively). As anticipated, there was a 19% reduction in drug exposure (AUC0(-∞)) when subjects received nano-formulated diclofenac 35 mg compared with diclofenac 50 mg under fasting conditions (1225 ± 322 h*ng/mL vs 1511 ± 389 h*ng/mL, respectively). Safety and tolerability were comparable between nano-formulated diclofenac and diclofenac.

CONCLUSION

The novel nano-formulated, lower-dose diclofenac demonstrated lower systemic exposure, comparable Cmax, and faster absorption compared with diclofenac. In light of the advisory issued by worldwide regulatory agencies regarding use of lowest effective doses, these data may permit use of lower NSAID doses that improve safety and tolerability while, at minimum, relieving pain similar to standard formulations.

Endoscopic evaluation of the gastro-duodenal tolerance of short-term analgesic treatment with 25 mg diclofenac-K liquid capsules

BACKGROUND

Diclofenac-potassium (diclofenac--K) 25 mg liquid capsule is absorbed more quickly than the tablet formulation. It offers potential for rapid pain relief, but may alter gastro-duodenal tolerability.

AIM

To evaluate the gastro-duodenal tolerance of diclofenac-K 25 mg liquid capsules vs. diclofenac-K 12.5 mg tablets, acetylsalicylic acid (ASA) 500 mg tablets and ibuprofen 200 mg liquid capsules.

METHODS

In an endoscopist-blinded, randomised, parallel-group study, volunteers received 15 doses of diclofenac-K 25 mg liquid capsules (n = 36), diclofenac-K 2 × 12.5 mg tablets (n = 36), ibuprofen 2 × 200 mg liquid capsules (n = 24) or ASA 2 × 500 mg tablets (n = 36) over 5 days. The primary outcome was the incidence of erosive gastro-duodenal lesions at Day 6. Secondary outcomes included modified Lanza score and change in gastric mucosal prostaglandin synthesis.

RESULTS

The lowest incidence of erosive gastro-duodenal lesions was with diclofenac-K liquid capsules (53%), compared to 61% with diclofenac-K tablets (P = 0.52), 75% with ibuprofen (P = 0.08) and 94% with ASA (P = 0.001). Results were similar for the Lanza scores, although diclofenac-K liquid capsules were significantly superior to ibuprofen liquid capsules (P = 0.04). Diclofenac-K liquid capsules inhibited prostaglandin synthesis by 52% compared to 64% for diclofenac-K tablets (P = 0.10), 50% for ibuprofen (P = 0.85) and 79% for ASA (P = 0.002). With respect to safety, adverse events were most frequent in the ASA group, predominantly gastrointestinal events.

CONCLUSIONS

Mucosal injury with diclofenac-K liquid 25 mg liquid capsules was similar to diclofenac-K 25 mg tablets, significantly lower than ASA 1 g tablets and showed some superiority over ibuprofen 400 mg liquid capsules (EudraCT Number 2009-011278-14).

Over-the-counter ibuprofen and risk of gastrointestinal bleeding complications: a systematic literature review

BACKGROUND

Exposure to over-the-counter (OTC) ibuprofen and other OTC non-steroidal anti-inflammatory drugs (NSAIDs) is substantial. Although the literature on gastrointestinal (GI) safety of NSAID therapy is extensive, the risk profiles of OTC and prescription dosing are seldom separated, and few studies provide risks specific to OTC ibuprofen.

OBJECTIVE

To conduct a literature review to evaluate the risk of GI bleeding events related to OTC ibuprofen use.

METHODS

Published clinical trials, observational studies, and meta-analyses of OTC ibuprofen use, defined as up to 1200 mg/day or stated as 'over the counter,' reporting endpoints of incidence rates and proportions of GI bleeding events (e.g., GI bleeding-related hospitalizations and deaths) were identified via MEDLINE through 2010. Data from these studies were summarized.

RESULTS

Twenty studies (nine observational, ten clinical trials, one meta-analysis) reporting incidence rates and proportions of a GI bleeding-related event associated with OTC or OTC-specific doses of ibuprofen were included. The frequency of a GI-related hospitalization was <0.2% for patients on OTC-comparable doses. Incidence rates among those using OTC-comparable doses ranged from 0 to 3.19 per 1000 patient-years. The incidence of a GI bleeding-related event increased with age and the use of concomitant medications, and there was a general, though not always statistically significant, ibuprofen dose-response relationship. The relative risk of any GI bleeding-related event ranged from 1.1 to 2.4 for users of OTC-specific doses of ibuprofen compared to non-users.

CONCLUSIONS

Studies reported low incidence of GI bleeding events with use of OTC ibuprofen. Few published studies that specifically investigated OTC ibuprofen use were identified. Varying methodologies and definitions of exposure and outcomes prevented direct comparison of many results. Only studies that used the methods herein described were identified. Further research evaluating the risk of GI bleeding events in patients taking OTC-specific ibuprofen use may be useful.

Onset of action of diclofenac potassium liquid-filled capsules in dental surgery patients

OBJECTIVE

Diclofenac potassium soft gelatin capsules (DPSGC) are a low-dose, liquid-filled formulation that uses patented dispersion technology to facilitate rapid and consistent gastrointestinal absorption. Onset of pain relief experienced by patients receiving DPSGC was evaluated in two dental pain studies. Confirmed perceptible pain relief was evaluated in a post hoc analysis from these randomized controlled trials.

RESEARCH DESIGN AND METHODS

Adult patients (n = 514) were enrolled in two multicenter, parallel group, double-blind, placebo-controlled studies. Patients undergoing third molar extraction and experiencing a requisite level of pain (≥50 mm on a 100-mm visual analog scale within 4 hours post-surgery) were randomized to receive single doses of DPSGC 25 mg, 50 mg, 100 mg, or placebo. Pain was assessed at baseline and during 6 hours after dosing. Times to onset of perceptible and meaningful pain relief were recorded using the two-stopwatch method. Confirmed perceptible pain relief was determined in the DPSGC and placebo groups by calculating the median time to onset of perceptible pain relief (first stopwatch) in only those individuals who reported meaningful pain relief (second stopwatch).

RESULTS

More than 80% of patients achieved confirmed perceptible pain relief in the DPSGC groups compared with less than 30% of patients in the placebo group (Study 1 and Study 2, p < 0.0001). The median time to onset of confirmed perceptible pain relief in the two studies was less than 30 minutes for patients receiving any dose of DPSGC and more than 360 minutes in the placebo group (Study 1 and Study 2, p < 0.0001). DPSGC was well tolerated and no serious adverse events were reported. Study design limitations include the short duration of the trial and evaluation of a relatively limited patient population.

CONCLUSIONS

These results indicate that DPSGC was efficacious in providing a rapid onset of confirmed perceptible pain relief within 30 minutes of administration in these single dose postoperative dental pain studies.

A pharmacokinetic analysis of diclofenac potassium soft-gelatin capsule in patients after bunionectomy

The clinical utility of diclofenac potassium, a nonsteroidal anti-inflammatory drug, may be lessened by inconsistent gastrointestinal absorption. Diclofenac potassium liquid filled soft-gelatin capsule (DPSGC) is an investigational formulation that uses ProSorb dispersion technology to facilitate rapid and consistent gastrointestinal absorption. In this study, the pharmacokinetic (PK) properties of DPSGC are investigated and compared with a commercially available oral diclofenac potassium tablet in patients after primary unilateral first metatarsal bunionectomy. In an open-label, randomized study, 53 patients received ProSorb-D 12.5 mg (the liquid equivalent of DPSGC), DPSGC 25 mg, DPSGC 50 mg, or immediate-release diclofenac potassium 50-mg tablet administered every 8 hours for a 24-hour inpatient period followed by 7 days of outpatient dosing. Diclofenac steady-state PK was evaluated over an 8-hour sampling period 4 days after surgery. Delayed and/or multiple peaks in the diclofenac plasma concentration-time course profiles occurred more frequently with the commercially available oral diclofenac potassium 50-mg tablet than with the other DPSGC formulations. PK data for ProSorb-D 12.5-mg liquid, DPSGC 25 mg, DPSGC 50 mg, and diclofenac potassium 50-mg tablet revealed mean peak plasma concentrations (Cmax) of 302, 749, 1006, and 902 ng/mL, respectively, whereas area under the plasma concentration curve values were 316, 595, 1029, and 1166 ng-hour/mL, respectively. Mean times to Cmax (tmax) were 0.49, 0.63, 0.95, and 1.26 h, respectively. When compared with absorption characteristics of diclofenac potassium 50-mg tablet, DPSGC was more rapidly and consistently absorbed after bunionectomy. These characteristics should be advantageous when rapid pain relief is desired.

Modern management of mild-to-moderate joint pain due to osteoarthritis: a holistic approach

Osteoarthritis (OA) is the most common form of arthritis and it is often associated with significant disability and impaired quality of life. Once thought to be caused by an age-related 'wearing out' of articular cartilage, it is now recognized to be a dynamic process in which cartilage degradation alternates with repair. Several expert guidelines for the management of OA exist, which concur in their recommendations for a stepwise approach to the employment of pharmacological agents and the introduction of suggestions to extend the use of agents such as topical non-steroidal anti-inflammatory drugs, especially for mild-to-moderate forms of the disease. They also emphasize the importance of non-pharmacological measures, such as nutraceuticals, education, diet, exercise and the use of aids in improving signs and symptoms and slowing progression. In many countries, effective medicinal and nutraceutical agents are available 'over-the-counter'. This review explains the modern approach to the management of mild-to-moderate osteoarthritic pain.

Controlled phase III clinical trial of diclofenac potassium liquid-filled soft gelatin capsule for treatment of postoperative dental pain

PURPOSE

The purpose of the present study was to assess the safety and efficacy of oral diclofenac potassium liquid-filled soft gelatin capsule (DPSGC) that uses ProSorb dispersion technology (Xanodyne Pharmaceuticals, Inc, licensed from AAIPharma, Wilmington, NC), to treat adult patients with acute pain after third molar extraction.

PATIENTS AND METHODS

In the present multicenter, randomized, double-blind, placebo-controlled trial, patients experiencing a baseline level of pain (≥ 50 mm on a 100-mm visual analog scale within 4 hours after surgery) were randomized to receive a single dose of DPSGC at 25, 50, or 100 mg or placebo. Pain intensity and relief were assessed for 6 hours after dosing. The efficacy endpoints included the summed pain intensity difference, total pain relief, and the median time to the onset of perceptible and meaningful pain relief (using the 2-stopwatch method).

RESULTS

A total of 249 randomized patients had a significant increase in the summed pain intensity difference and total pain relief values at 3 and 6 hours across all DPSGC-treated groups compared with the placebo group (P < .0001). The onset of perceptible and meaningful pain relief was significantly faster in all DPSGC groups than in the placebo group, including the DPSGC 25-mg group (25 minutes [P = .0002] and 52 minutes [P < .0001] for perceptible and meaningful pain relief, respectively). Significantly fewer patients in the DPSGC groups required rescue medication compared with those in the placebo group (P < .0001). The global evaluation scores were significantly greater for the patients who received DPSGC than for those who received placebo (P < .0001), and more than 65% of DPSGC-treated patients rated the medication as good, very good, or excellent compared with 18% of the placebo-treated patients. DPSGC was generally well tolerated, and no serious adverse events were reported.

CONCLUSIONS

The results from the present single-dose study of postoperative dental pain suggest that DPSGC offers significant pain relief compared with placebo and that the study medication provided was well tolerated by patients who required pain relief after third molar extraction.

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.

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.

Synthesis of stimuli-responsive microgels for in vitro release of diclofenac diethyl ammonium

Thermal and dual stimuli-responsive microspheres (pH and temperature) were prepared by free radical polymerization of methacrylate bovine serum albumin (BSA-MA) as cross-linker and sodium methacrylate (NaMA) and/or N-isopropylacrylamide (NIPAAm), as hydrophilic/pH-sensitive and thermo-responsive monomers, respectively. Microgels were characterized by infrared spectroscopy, morphological analysis, particle size distribution and determination of swelling properties. The network density and the shape of the microgels were found to depend on the concentration of the reactive species in the polymerization feed. Thermal analyses were performed to determine lower critical solution temperature values, which become close to the body temperature by increasing the content of the hydrophilic moieties in the network. In order to test the preformed materials as drug carriers, in vitro release studies of Diclofenac diethyl ammonium salt were performed. For all the co-polymers, a predominant drug release in the collapsed state was observed, while below the microgel transition temperature, a drug release through the swollen network occurs. The data recorded during the release tests demonstrated that the pH of the surrounding environment influences the drug release more than the temperature of the imbibing medium.

Diclofenac potassium liquid-filled soft gelatin capsules in the management of patients with postbunionectomy pain: a Phase III, multicenter, randomized, double-blind, placebo-controlled study conducted over 5 days

BACKGROUND

Diclofenac potassium liquid-filled soft gelatin capsule (DPSGC) is a rapidly absorbed formulation of diclofenac potassium developed for the treatment of mild to moderate acute pain.

OBJECTIVE

The present study was conducted to assess the efficacy and safety profile of DPSGC 25 mg in patients with pain after first-metatarsal bunionectomy.

METHODS

This was a Phase III, multicenter, randomized, double-blind, parallel-group, placebo-controlled study conducted over 5 days. Patients experiencing the requisite level of pain (score > or = 4 on an 11-point numeric pain rating scale [NPRS] from 0 = no pain to 10 = worst possible pain) on the day after bunionectomy were randomized to receive DPSGC 25 mg or matching placebo. A second dose was given when patients requested additional medication for pain. Subsequent doses were given every 6 hours over a 48-hour inpatient multiple-dose period and continued over an additional 48-hour outpatient multiple-dose period. Opioid rescue medication was available as needed after the second dose of study medication. The primary efficacy end point was the mean NPRS score over the 48-hour inpatient multiple-dose period. Additional measures included NPRS scores at predefined times over 48 hours, the summed pain intensity difference over 48 hours (SPID48), the time-weighted sum of pain relief scores over the first 8 hours, the mean dosing interval (the time from dosing to the time rescue medication or the next dose of study medication was administered, whichever was less), the proportion of patients requiring rescue medication, and the onset of perceptible and meaningful pain relief (2-stopwatch method). Tolerability was assessed based on physician monitoring and patient reporting of adverse events (AEs) and the results of standard laboratory tests.

RESULTS

Of 201 randomized patients (102 DPSGC 25 mg, 99 placebo; 86.6% female; 58.2% white; mean [SD] age, 45.2 [11.5] years; weight range, 49.4-108.0 kg), 198 completed the study. Mean baseline NPRS scores did not differ significantly between the DPSGC and placebo groups (6.9 and 7.3, respectively). DPSGC was associated with significant improvements compared with placebo in mean NPRS score over 48 hours (2.5 vs 5.6, respectively; P < 0.001), mean SPID48 (210.0 vs 90.3; P < 0.001), and overall mean dosing interval (331.5 vs 263.9 min; P < 0.001). Significant differences in NPRS scores between DPSGC 25 mg and placebo were noted at all time points from baseline through 48 hours (P < 0.001). The proportion of patients requiring rescue medication was significantly lower in the DPSGC group compared with the placebo group (39.2% vs 87.9% on day 1; 21.6% vs 64.6% on day 2; both, P < 0.001). Patients receiving DPSGC had a significantly faster onset of meaningful pain relief compared with those receiving placebo (P = 0.008). The most commonly reported AEs were nausea (7.8% vs 18.2%), headache (5.9% vs 9.1%), vomiting (3.9% vs 9.1%), and constipation (3.9% vs 2.0%). The overall incidence of AEs occurring in > or = 2% of patients was significantly lower in the DPSGC group than in the placebo group (20.6% vs 44.4%; P < 0.05); no patient receiving DPSGC had a serious AE.

CONCLUSIONS

DPSGC 25 mg taken every 6 hours was effective in reducing postbunionectomy pain in the patients studied. DPSGC was well tolerated, suggesting that it may be a practicable option for the treatment of mild to moderate acute pain. ClinicalTrials. gov identifier: NCT00366444.

Effects of food intake on the pharmacokinetics of diclofenac potassium soft gelatin capsules: a single-dose, randomized, two-way crossover study

BACKGROUND

Diclofenac potassium liquid-filled soft gelatin capsule (DPSGC) is an investigational formulation that uses dispersing agents designed to facilitate rapid and consistent absorption of this NSAID.

OBJECTIVE

The aim of this study was to characterize the effects of food intake on the pharmacokinetic (PK) profile of oral DPSGC at doses of 25 and 50 mg.

METHODS

In this open-label, randomized, single-dose (2 distinct doses), 2-way crossover bioavailability study, healthy adult volunteers were randomly assigned to receive a single dose of DPSGC 25 or 50 mg after an overnight fast (fasted condition) or high-fat breakfast (fed condition) (period 1). After 7 days, the participants received the same dose under the opposite fed/fasted condition (period 2). Serial blood samples were obtained before and through 6 hours after study drug administration. Concentrations of diclofenac in plasma were determined using HPLC, and PK profiles were studied using ANCOVA. Adverse events (AEs) were monitored and recorded on each in-clinic day.

RESULTS

Of 47 participants included in the study, 24 received the 25-mg dose of DPSGC and 23 received the 50-mg dose. The majority of participants were male (80.9%), and the mean age was 28.6 years. The mean (SD) AUC values for the fasted and fed states were 691 (195) and 680 (184) ng x h/mL, respectively, with the 25-mg dose, and 1521 (377) and 1416 (366) ng . h/mL, respectively, with the 50-mg dose, suggesting that the extent of absorption was similar with both dietary conditions at each dose. Food intake was associated with decreases in C(max) by nearly half in the 25-mg group (fasted vs fed, 1156 [482] vs 686 [411] ng/mL, respectively; P < 0.05) and the 50-mg group (2365 [1034] vs 1154 [592 ng/mL; P < 0.05) and delayed T(max) in the 25-mg group (0.49 [0.16] vs 1.02 [0.55] hours; P < 0.05) and 50-mg group (0.51 [0.19] vs 1.28 [0.71] hours; P < 0.05). Two mild AEs (nasal congestion and light-headedness) were reported in 2 participants who received 25 mg under fed conditions and 50 mg under fasted conditions, respectively.

CONCLUSIONS

Food intake did not appear to affect the extent of absorption (ie, total exposure) of oral DPSGC at doses of 25 and 50 mg in these healthy adult volunteers. Both single doses appeared to be well tolerated.

Phytalgic, a food supplement, vs placebo in patients with osteoarthritis of the knee or hip: a randomised double-blind placebo-controlled clinical trial

Introduction

The medicinal treatment of osteoarthritis (OA) is mostly symptomatic to relieve pain and incapacity with analgesics and non-steroidal anti-inflammatory drugs (NSAIDs), drugs with well-known risks. Complementary medicines might reduce the symptoms of OA and decrease the need for NSAIDs. This study tested the effects of a food supplement, Phytalgic^®, on pain and function in patients with osteoarthritis and their use of analgesic and NSAIDs.

Methods

A randomized double-blind parallel-groups clinical trial compared Phytalgic^® (fish-oil, vitamin E, Urtica dioica) to a placebo for three months, in 81 patients with OA of the knee or hip using NSAIDs and/or analgesics regularly. The main outcome measures were use of NSAIDs (in Defined Daily Doses per day - DDD/day) or analgesics (in 500 mg paracetamol-equivalent tablets per week (PET/week) measured each month, and Western Ontario-McMaster University Osteo-Arthritis Index (WOMAC) function scales.

Results

After three months of treatment, the mean use of analgesics in the active arm (6.5 PET/week) vs. the placebo arm (16.5) was significantly different (P < 0.001) with a group mean difference of -10.0 (95% CI: -4.9 to -15.1). That of NSAIDs in the active arm (0.4 DDD/day) vs the placebo arm (1.0 DDD/day) was significantly different (P = 0.02) with a group mean difference of - 0.7 DDD/day (95% CI: -0.2 to -1.2). Mean WOMAC scores for pain, stiffness and function in the active arm (respectively 86.5, 41.4 and 301.6) vs the placebo arm (resp. 235.3, 96.3 and 746.5) were significantly different (P < 0.001) with group mean differences respectively of -148.8 (95% CI: -97.7 to -199.9), -54.9 (95% CI: -27.9 to -81.9) and -444.8 (95% CI: -269.1 to -620.4).

Conclusions

The food supplement tested appeared to decrease the need for analgesics and NSAIDs and improve the symptoms of osteoarthritis.

Trial registration

Clinicaltrials.gov NCT00666523.

Systemic bioavailability of topical diclofenac sodium gel 1% versus oral diclofenac sodium in healthy volunteers

Systemic bioavailability and pharmacodynamics of topical diclofenac sodium gel 1% were compared with those of oral diclofenac sodium 50-mg tablets. In a randomized, 3-way crossover study, healthy volunteers (n = 40) received three 7-day diclofenac regimens: (A) 16 g gel applied as 4 g to 1 knee 4 times daily (4 g on surface area 400 cm(2)), (B) 48 g gel applied as 4 g per knee 4 times daily to 2 knees plus 2 g gel per hand applied 4 times daily to 2 hands (12 g on 1200 cm(2)), and (C) 150 mg oral diclofenac applied as 50-mg tablets 3 times daily. Thirty-nine participants completed all 3 regimens. Systemic exposure was greater with oral diclofenac (AUC(0-24), 3890 +/- 1710 ng x h/mL) than with topical treatments A (AUC(0-24), 233 +/- 128 ng x h/mL) and B (AUC(0-24), 807 +/- 478 ng x h/mL). Oral diclofenac inhibited platelet aggregation, cyclooxygenase-1 (COX-1), and COX-2. Topical diclofenac did not inhibit platelet aggregation and inhibited COX-1 and COX-2 less than oral diclofenac. Treatment-related adverse events were mild and limited to application site reactions with diclofenac sodium gel 1% (n = 4) and gastrointestinal reactions with oral diclofenac (n = 3). Systemic exposure with diclofenac sodium gel 1% was 5- to 17-fold lower than with oral diclofenac. Systemic effects with topical diclofenac were less pronounced.

Single-dose pharmacokinetic study of rapidly dispersing diclofenac potassium formulations in healthy volunteers

OBJECTIVE

The clinical utility of diclofenac potassium, a commonly prescribed analgesic that provides mild to moderate pain relief, may be hindered by its delayed, depressed, and/or inconsistent absorption characteristics. A diclofenac potassium formulation using proprietary dispersion technology (ProSorb) was developed to overcome these limitations. The authors evaluated and compared the pharmacokinetics (PK) of 2 investigational diclofenac potassium liquid filled soft gelatin capsule (DPSGC) preparations and one investigational diclofenac liquid formulation, each incorporating the proprietary dispersion technology, to establish bioequivalence and identify a formulation for further clinical study.

RESEARCH DESIGN AND METHODS

In an open-label, single-dose, three-way crossover, relative bioavailability study, 24 healthy volunteers were randomized to receive each of the 25-mg DPSGC formulations (development processes A and B) and the 1-mL (25-mg) liquid diclofenac formulation (similar to the fill liquid used in the DPSGC products) during three inpatient visits. Each dose was separated by 3 days. Plasma samples were collected at preselected time points through 6 hours post dose. Diclofenac concentrations were determined using a validated HPLC method. Bioequivalence was established within the 80% to 125% acceptance range. Safety and tolerability were monitored throughout.

RESULTS

Area under the plasma concentration-time curves (AUC(0-)(t)) for the three formulations were between 577 and 585 ng-hr/mL and peak plasma concentrations (C(max)) were between 958 and 1087 ng/mL, with the DPSGC process B group having the highest C(max). The times to C(max) (t(max)) were all below 30 minutes, with the liquid formulation producing the shortest t(max) (15 minutes). Plasma concentration-time course profiles were similar for all three rapidly dispersing diclofenac potassium formulations. One mild adverse event was observed (lingual paresthesia) and one participant discontinued due to an unrelated event (acute tonsillitis).

CONCLUSIONS

These data show that diclofenac potassium formulations using proprietary dispersion technology are rapidly and consistently absorbed. These characteristics may be beneficial in settings where rapid and consistent drug absorption is desirable. These results may differ in other patient populations such as those experiencing pain or illness.

Biowaiver monographs for immediate release solid oral dosage forms: diclofenac sodium and diclofenac potassium

Literature data are reviewed regarding the scientific advisability of allowing a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing either diclofenac potassium and diclofenac sodium. Within the biopharmaceutics classification system (BCS), diclofenac potassium and diclofenac sodium are each BCS class II active pharmaceutical ingredients (APIs). However, a biowaiver can be recommended for IR drug products of each salt form, due to their therapeutic use, therapeutic index, pharmacokinetic properties, potential for excipient interactions, and performance in reported BE/bioavailability (BA) studies, provided: (a) test and comparator contain the same diclofenac salt; (b) the dosage form of the test and comparator is identical; (c) the test product contains only excipients present in diclofenac drug products approved in ICH or associated countries in the same dosage form, for instance as presented in this paper; (d) test drug product and comparator dissolve 85% in 30 min or less in 900 mL buffer pH 6.8, using the paddle apparatus at 75 rpm or the basket apparatus at 100 rpm; and (e) test product and comparator show dissolution profile similarity in pH 1.2, 4.5, and 6.8.

Effects of plasticizers and surfactants on the film forming properties of hydroxypropyl methylcellulose for the coating of diclofenac sodium tablets

Hydroxy propyl methyl cellulose (HPMC) 5cPs, an aqueous soluble polymer was employed for coating diclofenac sodium (DFS) tablets 25 mg for protecting the integrity of the drug yet rendering the drug to release at a faster rate on contact with the gastric environment. Proper optimization for the aqueous based film coating formulation was undertaken primarily employing plasticizers like polyethylene glycol (PEG) 400 and propylene glycol (PG). The defect free selected formulations were further subjected for studying the effects of surfactants like sodium lauryl sulphate (SLS) and Tween-80 along with the plasticizers. The quality of the aqueous film coats or the plasticizer efficiency in case of PEG-400 is in the order 1.5 > 0.5 > 1.0% and for PG 1 > 4 > 3% which can be stated on the basis of less incidence of major coat defects like chipping, cracking, orange peel, roughness, blistering, blooming, picking. The quality of aqueous film coat or the surfactant efficiency in case of SLS + PEG-400 is in the order 0.3 < 0.5 < 0.1% and SLS + PG is in the order 0.5 < 0.1 < 0.3%. In case of Tween-80 + PEG-400 the order is 0.3 < 0.5 < 0.1% and Tween-80 + PG is in the order 0.3 < 0.1 < 0.5%. Elegant film formation can be stated from fewer incidences of coat defects. The obtained coated tablets eventually satisfied all the normal physical parameters like thickness, weights, and weight gain, drug content, crushing strength, percent friability, disintegration time, dissolution profile and possible drug-polymer interactions. ANOVA was undertaken followed by Dunnet multiple comparison for the dissolution profile considering uncoated as the standard. The difference was considered significant at p ⩽ 0.01.

Ibuprofen and other widely used non-steroidal anti-inflammatory drugs inhibit antibody production in human cells

The widely used non-steroidal anti-inflammatory drugs (NSAIDs) function mainly through inhibition of cyclooxygenases 1 and 2 (Cox-1 and Cox-2). Unlike Cox-1, Cox-2 is considered an inducible and pro-inflammatory enzyme. We previously reported that Cox-2 is upregulated in activated human B lymphocytes and using Cox-2 selective inhibitors that Cox-2 is required for optimal antibody synthesis. It is not known whether commonly used non-prescription and non-Cox-2 selective drugs also influence antibody synthesis. Herein, we tested a variety of Cox-1/Cox-2 non-selective NSAIDs, namely ibuprofen, tylenol, aspirin and naproxen and report that they blunt IgM and IgG synthesis in stimulated human peripheral blood mononuclear cells (PBMC). Ibuprofen had its most profound effects in inhibiting human PBMCs and purified B lymphocyte IgM and IgG synthesis when administered in the first few days after activation. As shown by viability assays, ibuprofen did not kill B cells. The implications of this research are that the use of widely available NSAIDs after infection or vaccination may lower host defense. This may be especially true for the elderly who respond poorly to vaccines and heavily use NSAIDs.

The therapeutic potential of neuronal K V 7 (KCNQ) channel modulators: an update

BACKGROUND

Neuronal KCNQ channels (K(V)7.2-5) represent attractive targets for the development of therapeutics for chronic and neuropathic pain, migraine, epilepsy and other neuronal hyperexcitability disorders, although there has been only modest progress in translating this potential into useful therapeutics.

OBJECTIVE

Compelling evidence of the importance of K(V)7 channels as neuronal regulatory elements, readily amenable to pharmacological modulation, has sustained widespread interest in these channels as drug targets. This review will update readers on key aspects of the characterization of these important ion channel targets, and will discuss possible current barriers to their exploitation for CNS therapeutics.

METHODS

This article is based on a review of recent literature, with a focus on data pertaining to the roles of these channels in neurophysiology. In addition, I review some of the regulatory elements that influence the channels and how these may relate to channel pharmacology, and present a review of recent advances in neuronal K(V)7 channel pharmacology.

CONCLUSIONS

These channels continue to be valid and approachable targets for CNS therapeutics. However, we may need to understand more about the roles of neuronal K(V)7 channels during the development of disease states, as well as to pay more attention to a detailed analysis of the molecular pharmacology of the different channel subfamily members and the modes of interaction of individual modulators, in order to successfully target these channels for therapeutic development.

Persistence of NSAIDs at effect sites and rapid disappearance from side-effect compartments contributes to tolerability

BACKGROUND

Non-steroidal, anti-inflammatory drugs (NSAIDs) are still the most widely used drugs worldwide. The introduction of selective cyclooxygenase (COX)-2 inhibitors has led to compounds which appear less damaging to the gastrointestinal tract, but possibly more risky to the cardiovascular system than older drugs. None has as yet reached OTC-status.

OBJECTIVE

This situation necessitates an analysis of the characteristics of those older ones which - due to their relative safety - have achieved over-the-counter (OTC) status.

DESIGN

The pharmacodynamic and pharmacokinetic characteristics of non-selective COX inhibitors in OTC use were obtained from the literature by systematic search, examined and used to construct a coherent hypothesis why they achieved OTC status, i.e. effectiveness and relative safety at low doses.

RESULTS

Pharmacodynamic (COX-2 preferential, but not selective inhibition) and, more importantly, pharmacokinetic characteristics of some of the older compounds may make them particularly safe drugs if used at low (OTC) doses with treatment limited to a few days of intake. The reason why some NSAIDs are particularly active while being relatively free from side-effects may be due to their specific biodistribution and metabolism, leading to drug accumulation and persistence in inflamed tissue (effect compartment) together with fast clearance from the central compartment, including blood, vascular wall, heart and kidney, i.e., possible sideeffect compartments.

CONCLUSION

This specific pharmacokinetic behavior of some non-selective COX inhibitors, such as diclofenac and ibuprofen, may explain why these widely used, non-steroidal, anti-inflammatory compounds are relatively well suited for OTC use and why some are more appropriate for the therapy of certain pain conditions than others.

Ibuprofen: A Journey from Prescription to Over-the-Counter Use

Ibuprofen was the first non-aspirin non-steroidal antiinflammatory drug (NSAID) to be approved for over-the-. counter (OTC) use and is widely considered to be the best tolerated drug of its class. Low-dose, OTC ibuprofen has been used for pain relief for over 30 years without any obvious major health issues. However, there is no clear differentiation between the OTC and prescription doses of ibuprofen, and their respective effects. Adverse reactions to ibuprofen appear to be dose and duration dependent, and this may be the reason for the observed tolerability of the drug at OTC doses. OTC ibuprofen is at least as effective as aspirin and more effective than paracetamol. The tolerability concerns associated with higher dose NSAIDs currently do not apply to low-dose, short-term use of ibuprofen for common pain. Ibuprofen is associated with the least risk of GI complications compared with other NSAIDs and is considered relatively benign in overdose. This review will aim to distinguish the safety of OTC or non-prescription use of ibuprofen from its prescription use.