Diclofenac sodium. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

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.

Efficacy and tolerability of a new powdered formulation of diclofenac potassium for oral solution for the acute treatment of migraine: results from the International Migraine Pain Assessment Clinical Trial (IMPACT)

OBJECTIVE

This study assessed the efficacy of diclofenac potassium for oral solution, a novel water-soluble buffered powder formulation, versus placebo for the acute treatment of migraine. Diclofenac potassium for oral solution has a time to maximum plasma concentration (Tmax) of 15 minutes, suggesting the potential for a rapid onset of therapeutic effects.

METHODS

This was a randomized, double-blind, parallel-group, placebo-controlled study conducted in 23 US centers. Adult sufferers with an established migraine diagnosis according to the International Classification of Headache Disorders, second edition (ICHD-II), treated one moderate or severe attack with 50 mg diclofenac potassium for oral solution (dissolved in approximately 2 ounces of water; N=343) or matching placebo (N=347). Four co-primary endpoints included the percentage of subjects who at two hours post-treatment reported no headache pain, no nausea, no photophobia and/or no phonophobia.

RESULTS

Significantly more subjects treated with diclofenac potassium for oral solution (N=343) achieved a two-hour pain-free response (25% vs. 10%, p<.001), no nausea (65% vs. 53%; p=.002), no photophobia (41% vs. 27%; p<.001) and no phonophobia (44% vs. 27%; p<.001) compared to placebo. Pain intensity differences between treatments were significantly lower in the diclofenac potassium oral solution group, starting at 30 minutes post-treatment (p=.013) with significant differences at all time points thereafter (p<.001). Twenty-four-hour sustained pain-free response favored diclofenac potassium oral solution treatment versus placebo (19% vs. 7%, p<.0001). The most common adverse event considered to be treatment related was nausea (diclofenac potassium for oral solution [4.6%]; placebo [4.3%]).

CONCLUSIONS

This study shows that this formulation of diclofenac potassium for oral solution is effective in reducing pain intensity within 30 minutes, which may be related to the 15-minute T(max) associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.

Diclofenac for acute pain in children

BACKGROUND

Diclofenac is commonly used for acute pain in children, but is not licensed for this indication in all age groups.

OBJECTIVES

1) Assess the efficacy of diclofenac for acute pain in children. 2) Assess the safety of diclofenac for short-term use in children. 3) Identify gaps in the evidence to direct future research.

SEARCH STRATEGY

Seventeen databases indexing clinical trial reports were searched in February 2005 (with an update search as part of this first review in May 2008). A hand search of Paediatric Anaesthesia was undertaken and summaries obtained of adverse reaction reports from the UK Yellow Card Scheme and World Health Organization (WHO) Monitoring Centre. The reference lists of included studies were also searched.

SELECTION CRITERIA

Any published report, in any language, involving the administration of diclofenac to a patient aged 18 years or younger for acute pain and detailing either monitoring of efficacy or safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted the data. Authors were contacted where necessary. Review Manager version 5 was used for analysis.

MAIN RESULTS

1) EFFICACY: randomised controlled trials (RCTs) comparing diclofenac with placebo/any other treatment by using pain scores (assessed or reported), or need for rescue analgesia.2) SAFETY: any type of study seeking adverse events (regardless of cause). An adverse event was defined as any reported adverse or untoward happening to a patient being treated with diclofenac for acute pain.Seven publications on diclofenac efficacy and 79 on safety (74 studies plus five case reports) were included in the final analysis. Compared with placebo/no treatment, diclofenac significantly reduced need for post-operative rescue analgesia (relative risk [RR] 0.6; number needed to treat to benefit [NNT] 3.6; 95% confidence interval [CI] 2.5 to 6.3).Compared with any other non-NSAID, patients receiving diclofenac suffered less nausea or vomiting, or both (RR 0.6; NNT 7.7 [5.3 to 14.3]). There appeared to be no increase in bleeding requiring surgical intervention in patients receiving diclofenac in the peri-operative period. Serious diclofenac adverse reactions occurred in fewer than 0.24% of children treated for acute pain. The types of serious adverse reactions were similar to those reported in adults.

AUTHORS' CONCLUSIONS

Diclofenac is an effective analgesic for perioperative acute pain in children. It causes similar types of serious adverse reactions in children as in adults, but these are rare. More research on optimum dosing and safety in asthmatic children is required.

Effect of rectal diclofenac in reducing postoperative pain and rescue analgesia requirement after cardiac surgery

BACKGROUND

Adequate analgesic medication is mandatory after coronary artery bypass grafting (CABG) surgery. The aim of this study was to assess the analgesic efficacy, side effects, and need for rescue analgesia after CABG surgery comparing diclofenac and placebo rectal suppository.

METHODS

Thirty-seven consenting adults undergoing elective CABG surgery were randomly assigned in a double-blind fashion to receive either rectal diclofenac 100 mg (Group 1, n = 19) or placebo suppository (Group 2, n = 18) postoperatively, just after extubation. Both groups were given intravenous tramadol as a rescue analgesic. Pain scores in the two groups were assessed on a 10-cm visual analog scale at 0, 0.5, 1, 1.5, 2, 6, 12, 18, and 24 hours after suppository administration. Rescue analgesic consumption, sedation, nausea, and vomiting in both the groups were also recorded.

RESULTS

Twenty-four-hour tramadol consumption in Group 1 was 92.5 +/- 33.5 mg compared to 157.5 +/- 63.4 mg in Group 2 (P = 0.002). Patients in the placebo group had significantly greater pain scores 1.5 to 12 hours after extubation. Group 1 patients were significantly more awake compared to Group 2 (P < 0.05). The incidence of postoperative nausea was less in Group 1 than in Group 2 (P = 0.001). Though not statistically significant, three patients in Group 2 each had a single episode of vomiting, whereas no patient had vomiting in Group 1.

CONCLUSION

Rectal diclofenac suppository with tramadol provides adequate pain relief after cardiac surgery, and also reduces tramadol consumption and side effects commonly associated with tramadol.

No difference between two doses of diclofenac in prophylaxis of heterotopic ossifications after total hip arthroplasty

BACKGROUND

In a monocentric, randomized, placebo-controlled double-blind study, we investigated the efficacy of two doses of diclofenac-cholestyramine for the prevention of heterotopic ossification (HO).

PATIENTS

The study comprised 245 patients undergoing total hip arthroplasty (THA).

RESULTS

With 150 mg cholestyramine-bound diclofenac (2 x 1 capsule Voltaren resinate) daily during a postoperative period of 14 days, 19% of patients showed slight HO (Brooker grade 1), and no patient had more severe ossifications (grades 2-4). In the group receiving 75 mg daily (1 x 1 capsule), 17% of patients showed grade 1 HO and 4% grade 2 HO. No patient had grades 3-4 HO. No differences in clinical results were seen between the two groups 6 months after THA.

INTERPRETATION

Since the rate of adverse gastrointestinal events was lower (23% versus 38%, p = 0.02) in the group receiving the lower dose, we recommend it.

Dose-dependent inhibition of diclofenac sodium on posterior lumbar interbody fusion rates

BACKGROUND CONTEXT

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) had been implicated as a risk factor for nonunion in spinal fusion. Even with a number of animal and human studies suggesting NSAIDs either delay or inhibit spinal fusion rates, these drugs continue to be used because of demonstrated benefits. Diclofenac sodium is no exception. It is very popular as a first-line treatment for acute pain, even perioperatively for spine fusion patients. Review of published literature reveals no studies done on the effect of diclofenac sodium on spine fusion rates.

PURPOSE

To determine if diclofenac sodium is a risk factor for delayed union and nonunion in adult patients who underwent one- to two-level instrumented posterior lumbar interbody fusion (PLIF) using only local autogenous bone graft.

STUDY DESIGN/SETTING

Retrospective, analytical.

PATIENT SAMPLE

Two hundred and seventy-three adult patients who underwent one- to two-level PLIF with minimum 2-year follow-up.

OUTCOME MEASURES

Diclofenac sodium intake, fusion status.

METHODS

Medical records and radiographs of 273 adult patients who underwent one- to two-level PLIF in a single institution from 1999 to 2004 were reviewed. All patients did not use any NSAID or steroid perioperatively, except for diclofenac sodium postoperatively. The amount of diclofenac sodium used was quantified for the first 14 days post-op. These patients were followed-up periodically for 2 years. Demographic data, levels fused, and NSAID intake were correlated to union status.

RESULTS

Nineteen out of the 273 patients had no diclofenac sodium intake (no-dose group), 168 patients used less than or equal to 300 mg (moderate-dose group), and 86 patients used more than 300 mg of diclofenac sodium (high-dose group). There were 4 nonunions and 41 delayed unions seen. No significant difference was seen when fusion status was compared with age, sex, L5-S1 versus other levels, and smoking history (all comparisons, p>.05). There was a significant difference between one- and two-level fusions in terms of union status (p=.002). There were no nonunions and 18 delayed unions seen in 217 patients in the single-level fusion group. All 4 nonunions and 23 delayed unions were noted among the 56 patients in the two-level group. There were no cases of delayed union and nonunion in the no-dose group. There were also no nonunions but 16 delayed unions in the moderate-dose group. There were 4 nonunions and 25 delayed unions in the high-dose group. As diclofenac sodium intake increases, the incidence of delayed union and nonunion were also seen to increase (p<.001). Time to union was correlated to the amount of diclofenac sodium intake using Pearson's correlation coefficient (r=0.271, p<.001). When the patients were divided into one- and two-level fusion groups, the amount of diclofenac sodium used still had a significant positive correlation to frequency of delayed union and nonunion and in time to union in each group (all comparisons, p<.05).

CONCLUSIONS

Diclofenac sodium showed a dose-dependent inhibitory effect toward spine fusion especially when used during the immediate postoperative period. No significant correlation was seen between age, sex, L5-S1 versus other levels fused and smoking history when compared with spine nonunion. Two-level lumbar fusions also showed a significant negative correlation to spine fusion compared with single-level fusions.

Oral versus topical diclofenac for pain prevention during panretinal photocoagulation

PURPOSE

To investigate the effect of pretreatment oral and topical diclofenac on pain reduction during panretinal laser photocoagulation (PRP) for proliferative diabetic retinopathy (PDR).

DESIGN

Prospective, randomized, double-masked, placebo-controlled clinical trial.

PARTICIPANTS AND CONTROLS

A total of 90 patients with PDR requiring PRP for the first time were assigned randomly to 1 of 3 study groups: oral diclofenac (n = 30), topical diclofenac (n = 31), or placebo (n = 29).

METHODS

Study medications were administrated before the first PRP treatment, and pain levels experienced during and 15 minutes after PRP were recorded on a visual analog scale (VAS). Pain levels during a second PRP session, performed on a later date with no pretreatment medications, also were recorded on a VAS.

MAIN OUTCOME MEASURES

The primary outcome measures were the mean VAS pain scores during the first PRP treatment. Secondary outcome measures were the mean VAS pain scores 15 minutes after the first PRP and during the second PRP, and reported side effects after the first PRP.

RESULTS

Mean VAS pain scores during the first PRP were: oral diclofenac, 25.7+/-19.9; topical diclofenac, 33.8+/-27.9; and placebo, 41.3+/-31.0. The pain score difference between oral diclofenac and placebo was both clinically significant (>or=13) and statistically significant (P = 0.02), whereas differences between oral and topical diclofenac (P = 0.20) and topical diclofenac and placebo (P = 0.33) were not. Multivariate regression analysis for age, gender, and total laser energy demonstrated lower pain levels for both oral diclofenac (P = 0.015) and topical diclofenac (P<0.0001) versus placebo, but no difference between oral and topical diclofenac (P = 0.67). For the first PRP, all 3 groups had lower mean pain scores at 15 minutes after treatment compared with during treatment (P<or=0.0003). Mean pain scores were higher during the second compared with the first PRP for the oral diclofenac (P = 0.02) and placebo (P = 0.05) groups. No significant rate difference for any side effect was found between groups.

CONCLUSIONS

When given in a single dose, oral diclofenac is an effective pretreatment analgesic agent for reducing the pain experienced during PRP for PDR.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Comparative assessment of the effectiveness and tolerability of lornoxicam 8 mg BID and diclofenac 50 mg TID in adult indian patients with osteoarthritis of the hip or knee: A 4-week, double-blind, randomized, comparative, multicenter study

BACKGROUND

Reports of cardiovascular adverse events (AEs) associated with the use of cyclooxygenase-2 inhibitors for the treatment of osteoarthritis (OA) have prompted the quest for a better-tolerated NSAID.

OBJECTIVE

The aim of this study was to compare the effectiveness and tolerability of lornoxicam 8 mg BID and diclofenac 50 mg TID in adult Indian patients with OA of the hip or knee.

METHODS

This 4-week, double-blind, randomized, comparative, multicenter study was undertaken to compare oral lornoxicam and diclofenac in patients with OA. Patients who met the selection criteria were enrolled consecutively from the outpatient clinics of each of the participating hospitals in India. Participants completed the Western Ontario and McMasters Individual Osteoarthritis Index (WOMAC-OA), WOMAC Composite Index (WOMAC-CI) (for pain, stiffness, and physical function), and a 10-cm visual analog scale (VAS) (0-10 where 0 = no pain and 10 = worst possible pain or severe or excruciating pain) at each study visit (weeks 0 [baseline], 2, and 4 [or at early termination]). Patients' and physicians' global assessments of arthritis control were measured at each study visit when laboratory and clinical AEs were also monitored. The primary end points were the WOMAC-OA, the WOMAC-CI, and VAS scores for pain among the patients who completed the study.

RESULTS

Of the 273 patients (159 men, 114 women; mean [SD] age, 44.73 [10.72] years; range, 28-68 years) enrolled in the study, 13 (7 in the lornoxicam group and 6 in the diclofenac group) were lost to follow-up and their effectiveness and tolerability results were not included in the study analysis. Over the 4-week study period, both drugs provided significant (P < 0.05) sustained relief of OA symptoms compared with baseline. Compared with baseline, the mean pain score (WOMAC-CI) decreased 90.6% (13.88 [4.47] vs 1.30 [1.49]; P < 0.05) in the lornoxicam group and 88.9% (14.15 [4.56] vs 1.57 [1.49]; P < 0.05) in the diclofenac group after 4 weeks of treatment. After 4 weeks of treatment, the VAS pain score decreased from baseline 83.1% (8.04 [2.70] vs 1.36 [1.43]; P < 0.05) in the lornoxicam group and 79.3% (7.98 [2.98] vs 1.65 [1.47]; P < 0.05) in the diclofenac group. Compared with baseline, the improvement rated at 2 weeks was not significantly different between the 2 groups. Lornoxicam and diclofenac were well tolerated. The rate of mild to moderate adverse gastrointestinal events was not significantly different in the lornoxicam group compared with the diclofenac group (14.6% vs 18.4%). Similarly, overall tolerability between the 2 groups was not significantly different. None of the patients experienced cardiovascular AEs (eg, edema or increased blood pressure).

CONCLUSION

The results of the present study suggest that lornoxicam was comparable to diclofenac in effectiveness and tolerability after 4 weeks of treatment in these adult Indian patients with OA of the hip or knee who completed the study.

Long-term NSAID treatment directly decreases COX-2 and mPGES-1 production in the articular cartilage of patients with osteoarthritis

OBJECTIVE

To simultaneously study the effect of a selective cyclooxygenase-2 (COX-2) inhibitor and that of a classic non-steroidal anti-inflammatory drug (NSAID) on the expression of pro-inflammatory genes in the cartilage of patients with severe knee osteoarthritis (OA) and in cultured human OA chondrocytes.

METHODS

A 3-month clinical trial was carried out on 30 patients with severe knee OA scheduled for knee replacement surgery. Patients were randomized into two groups: patients treated with celecoxib (CBX) and patients treated with aceclofenac (ACF). OA patients who did not want to be treated served as the control group. After surgery, cartilage was processed for molecular biology studies. We also employed cultured chondrocytes from different OA patients to examine NSAID effects on pro-inflammatory gene expression in cells stimulated with interleukin (IL)-1beta.

RESULTS

Both CBX and ACF inhibited COX-2, microsomal prostaglandin E synthase-1 (mPGES-1) and inducible nitric oxide synthase (iNOS) synthesis in the articular cartilage of OA patients. In cultured chondrocytes, both NSAID decreased COX-2 and mPGES-1 synthesis and prostaglandin E2 (PGE2) release induced by IL-1beta, while no effect was observed on nitric oxide or iNOS synthesis. In OA patients, only CBX decreased tumor necrosis factor alpha and IL-1beta expression in the cartilage, while both NSAID diminished IL-1beta induced cytokine synthesis in cultured OA chondrocytes.

CONCLUSIONS

Both NSAID diminished PGE2 release and induced a decrease in COX-2 and mPGES-1 synthesis in the cartilage from OA patients and in OA chondrocytes. These data suggest that prolonged therapy with PGE2 blocking agents decreases PGE2 production not only by direct inhibition of COX-2 activity, but also by down-regulating COX-2 and mPGES-1 synthesis in the cartilage. However, CBX and ACF seem to have a different anti-inflammatory profile in controlling pro-inflammatory gene expression in the cartilage.

Diclofenac sodium injection (Dyloject): in postoperative pain

*A new formulation of the nonselective NSAID diclofenac sodium suitable for intravenous bolus injection has been developed using hydroxypropyl beta-cyclodextrin as a solubility enhancer (HPbetaCD diclofenac). * HPbetaCD diclofenac intravenous bolus injection was shown to be bioequivalent to the existing parenteral formulation of diclofenac containing propylene glycol and benzyl alcohol as solubilizers (PG-BA diclofenac), which is relatively insoluble and requires slow intravenous infusion over 30 minutes. * Single-dose HPbetaCD diclofenac 3.75, 9.4, 18.75, 25, 37.5, 50 and 75 mg administered by intravenous bolus injection produced significantly greater responses than placebo for total pain relief (TOTPAR) over 6 hours or pain intensity at 4 hours in the treatment of moderate or severe postoperative dental pain in randomized, double-blind trials. HPbetaCD diclofenac 37.5 and 75 mg were similar in efficacy to intravenous bolus ketorolac 30 mg. * In a well controlled trial, single-dose HPbetaCD diclofenac 75 mg intravenous bolus injection was shown to be superior to PG-BA diclofenac 75 mg intravenous infusion with respect to TOTPAR over 4 hours, indicating faster onset of analgesia in the treatment of moderate or severe postoperative dental pain. Both HPbetaCD diclofenac and PG-BA diclofenac were superior to placebo. * HPbetaCD diclofenac was generally well tolerated during single-dose treatment of postoperative pain. The tolerability profile was similar to that of PG-BA diclofenac, but with a lower incidence of thrombophlebitis.

Design and optimization of diclofenac sodium controlled release solid dispersions by response surface methodology

A 3(2) factorial design was employed to produce controlled release solid dispersions of diclofenac sodium in Eudragit RS and RL by coevaporation of their ethanol solution in a flash evaporator. The effect of critical formulation variables namely total polymer pay loads and levels of Eudragit RL on percent drug incorporation (% DI), drug release at the end of 12 hours (Rel(12)) and drug release at the end of 3 hours (Rel(3)) were analyzed using response surface methodology. The parameters were evaluated using the F test and mathematical models containing only the significant terms were generated for each parameter using multiple linear regression analysis and analysis of variance. Both the formulation variables studied exerted a significant influence (p < 0.05) on the drug release whereas the total polymer levels emerged as a lone factor significantly influencing the percent drug incorporation. Numerical optimization technique employing desirability approach was used to develop a new formulation by setting constraints on the dependent and independent variables. The experimental values of % DI, Rel(12) and Rel(3) for the optimized batch were found to be 95.22 +/- 1.13%, 74.52 +/- 3.16% and 29.37 +/- 1.26% respectively which were in close agreement with those predicted by the mathematical models. The Fourier transform infrared spectroscopy, Differential scanning calorimetry and Powder x-ray diffractometry confirmed that the drug was reduced to molecular or microcrystalline form in the hydrophobic polymeric matrices, which could be responsible for the controlled drug release from the solid dispersions. The drug release from the solid dispersions followed first order rate kinetics and was characterized by Higuchian diffusion model.

Effects of anti-inflammatory drugs on proliferation, cytotoxicity and osteogenesis in bone marrow mesenchymal stem cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) were found to suppress proliferation and induce cell death in cultured osteoblasts, and steroids were found to decrease the osteogenesis potential of mesenchymal stem cells. In this study, we further tested the effects of anti-inflammatory drugs (AIDs) on the functions of bone marrow mesenchymal stem cells (BMSCs). The BMSCs from mice (D1-cells) and humans (hBMSCs) were treated with dexamethasone (10(-7) to 10(-6) M), cyclooxygenase-2 (COX-2) selective NSAIDs (10(-6) to 10(-5) M) and non-selective NSAIDs (10(-5) to 10(-4) M). Drug effects on proliferation, cell cycle kinetics, cytotoxicity and mRNA and protein expressions of cell cycle regulators were tested. The osteogenesis potential of D1-cells were evaluated by testing mRNA expressions of type Ialpha collagen and osteocalcin 2-8 days after treatments, and testing mineralization 1-3 weeks after treatments. The results showed that all the tested drugs suppressed proliferation and arrested cell cycle of D1-cells, but no significant cytotoxic effects was found. Prostaglandin E1, E2 and F2alpha couldn't rescue the effects of AIDs on proliferation. The p27kip1 expression was up-regulated by indomethacin, celecoxib and dexamethasone in both D1-cells and hBMSCs. Higher concentrations of indomethacin and dexamethasone also up-regulated p21Cip1/Waf1 expression in hBMSCs, and so did celecoxib on D1-cells. Expressions of cyclin E1 and E2 were down-regulated by these AIDs in D-cells, while only cyclin E2 was down-regulated by dexamethasone in hBMSCs. All the tested NSAIDs revealed no obvious detrimental effects on osteogenic differentiation of D1-cells. These results suggest that the proliferation suppression of AIDs on BMSCs may act via affecting expressions of cell cycle regulators, but not prostaglandin-related mechanisms.

Antagonism of thromboxane receptors by diclofenac and lumiracoxib

BACKGROUND AND PURPOSE

Non-steroidal anti-inflammatory drugs (NSAIDs) are analgesic and anti-inflammatory by virtue of inhibition of the cyclooxygenase (COX) reaction that initiates biosynthesis of prostaglandins. Findings in a pulmonary pharmacology project gave rise to the hypothesis that certain members of the NSAID class might also be antagonists of the thromboxane (TP) receptor.

EXPERIMENTAL APPROACH

Functional responses due to activation of the TP receptor were studied in isolated airway and vascular smooth muscle preparations from guinea pigs and rats as well as in human platelets. Receptor binding and activation of the TP receptor was studied in HEK293 cells.

KEY RESULTS

Diclofenac concentration-dependently and selectively inhibited the contraction responses to TP receptor agonists such as prostaglandin D2 and U-46619 in the tested smooth muscle preparations and the aggregation of human platelets. The competitive antagonism of the TP receptor was confirmed by binding studies and at the level of signal transduction. The selective COX-2 inhibitor lumiracoxib shared this activity profile, whereas a number of standard NSAIDs and other selective COX-2 inhibitors did not.

CONCLUSIONS AND IMPLICATIONS

Diclofenac and lumiracoxib, in addition to being COX unselective and highly COX-2 selective inhibitors, respectively, displayed a previously unknown pharmacological activity, namely TP receptor antagonism. Development of COX-2 selective inhibitors with dual activity as potent TP antagonists may lead to coxibs with improved cardiovascular safety, as the TP receptor mediates cardiovascular effects of thromboxane A2 and isoprostanes.

Analgesic, anti-inflammatory and hypoglycaemic effects of Rhus chirindensis (Baker F.) [Anacardiaceae] stem-bark aqueous extract in mice and rats

In an attempt to scientifically evaluate some of the anecdotal, folkloric, ethnomedical uses of Rhus chirindensis Baker F. ('red currant'), the present study was undertaken to investigate the analgesic, anti-inflammatory and hypoglycaemic effects of the plant's stem-bark aqueous extract (RCE) in mice and rats. The analgesic effect of RCE was evaluated by 'hot-plate' and 'acetic acid' analgesic test methods in mice; while its anti-inflammatory and hypoglycaemic effects were investigated in rats, using fresh egg albumin-induced pedal oedema, and streptozotocin (STZ)-induced diabetes mellitus animal models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. RCE (50-800 mg/kg i.p.) produced dose-dependent, significant (P<0.05-0.001) analgesic effects against thermally- and chemically-induced nociceptive pain in mice. The plant's extract (RCE, 50-800 mg/kg p.o.) also significantly (P<0.05-0.001) inhibited fresh egg albumin-induced acute inflammation, and caused dose-related, significant (P<0.05-0.001) hypoglycaemia in normal (normoglycaemic) and diabetic (hyperglycaemic) rats. The flavonoids, triterpenoids and other chemical compounds present in RCE are speculated to account for the observed pharmacological effects of the plant's extract in the experimental animal paradigms used. The findings of this experimental animal study indicate that Rhus chirindensis stem-bark aqueous extract possesses analgesic, anti-inflammatory and hypoglycaemic properties; and thus lend pharmacological credence to the anecdotal, folkloric, ethnomedical uses of the plant in the treatment and/or management of painful, arthritic, inflammatory conditions, as well as in the management and/or control of type 2 diabetes mellitus in some rural communities of South Africa.

Therapy insight: the use of antirheumatic drugs during nursing

In 90% of cases, women with rheumatoid arthritis suffer a disease flare within 3 months of delivery of their baby. Drug treatment is, therefore, required; however, such therapies have implications for mothers who decide to nurse their infants. Unfortunately, because of a paucity of data, little is known about the transfer of antirheumatic drugs into breast milk, and even less is known about whether small amounts of these agents ingested during nursing could harm the infant. Our review of the literature indicates that paracetamol, prednisone, antimalarial agents, sulfasalazine and most NSAIDs can safely be used by lactating mothers. Expert opinions differ regarding the use of azathioprine, ciclosporin, and methotrexate during lactation because of varying views on the potential for short-term and long-term adverse effects. Evidence regarding the transfer of leflunomide and biologic drugs into breast milk is insufficient; therefore, until more studies are conducted, the use of these drugs in breastfeeding mothers should be restricted. At present, many patients feel they have to choose between postpartum disease control and lactation. Extended studies of the transfer of antirheumatic drugs into breast milk and the resulting consequences are, therefore, urgently needed.

Valdecoxib provides effective pain relief following acute ankle sprain

We sought to determine whether valdecoxib is as effective as diclofenac in treating acute ankle sprain. Patients (n=202) with acute first- and second-degree ankle sprain were randomized to valdecoxib (40 mg twice daily on day 1 followed by 40 mg once daily on days 2-7) or diclofenac (75 mg twice daily). The primary efficacy end-point was the Patient's Assessment of Ankle Pain visual analogue scale (VAS, 0-100 mm) value on day 4. Valdecoxib was as efficacious as diclofenac in treating the signs and symptoms of acute ankle sprain. The mean VAS reduction in ankle pain on day 4 was not different between groups; the two-sided 95% confidence interval for the between-group difference was within the prespecified limit for non-inferiority (10 mm). There were no significant differences between groups for all secondary efficacy end-points. The two treatments were similarly effective and well tolerated for treatment of acute ankle sprain.

Release characteristics of diclofenac sodium from poly(vinyl alcohol)/sodium alginate and poly(vinyl alcohol)-grafted-poly(acrylamide)/sodium alginate blend beads

In this study, acrylamide (AAm) was grafted onto poly(vinyl alcohol) (PVA) with UV radiation at ambient temperature. The graft copolymer (PVA-g-PAAm) was characterized by using Fourier transform infrared spectroscopy (FTIR), elemental analysis and differential scanning calorimetry (DSC). Polymeric blend beads of PVA-g-PAAm and PVA with sodium alginate (NaAlg) were prepared by cross-linking with glutaraldehyde (GA) and used to deliver a model anti-inflammatory drug, diclofenac sodium (DS). Preparation condition of the beads was optimized by considering the percentage entrapment efficiency, particle size, swelling capacity of beads and their release data. Effects of variables such as PVA/NaAlg ratio, acrylamide content, exposure time to GA and drug/polymer ratio on the release of DS were discussed at three different pH values (1.2, 6.8, 7.4). It was observed that, DS release from the beads decreased with increasing PVA/NaAlg (m/m) ratio, drug/polymer ratio (d/p) and extent of cross-linking. However, DS release increased with increasing acrylamide content of the PVA-g-PAAm polymer. The highest DS release was obtained to be 92% for 1/1 PVA-g-PAAm/NaAlg ratio beads. It was also observed from release results that DS release from the beads through the external medium is much higher at high pH (6.8 and 7.4) than that at low pH (1.2). The drug release from the beads mostly followed Case II transport.

Is it safe to use topical NSAIDs for corneal sensitivity in Sjögren’s syndrome patients?

Sjögren's syndrome dry eye is an inflammatory disease accompanied by an impairment of the autonomous nervous system of the ocular surface. The therapy for this condition is shifting from the mere tear replacement to a more complex approach including an anti-inflammatory treatment. Clinical trials have evidenced that the use of NSAIDs is followed by a reduction of the ocular discomfort symptoms in dry-eye patients. However, sporadic case reports of corneal melting in dry-eye subjects who underwent surgical procedures has brought attention to the possible effect that NSAIDs may have on corneal sensitivity. Therefore, the effect of NSAID treatment on corneal sensitivity in normal subjects and in patients with dry eye was studied. The results of these trials seem to demonstrate that some NSAIDs, diclofenac in particular, have the effect of reducing corneal sensitivity both in normal subjects and in patients with dry eye. Therefore, NSAIDs should be used with caution in Sjögren's syndrome patients.

Release of diclofenac sodium from polylactide-co-glycolide 80/20 rods

Due to inflammatory reactions complicating bioabsorbable devices, the aim of this study was to develop and characterize bioabsorbable implants with anti-inflammatory drug releasing properties. Polylactide-co- glycolide (PLGA) 80/20 was compounded with diclofenac sodium (DS) to produce rods. Thermal properties were analyzed using differential scanning calorimetry (DSC). Inherent viscosity (eta(inh)) was measured to evaluate the drug effect on the extrude polymer. Drug release measurements were performed using UV-spectrophotometer. Five parallel samples from each type of rods were examined, first at 6 hour intervals, then on daily basis, and later twice a week. DS was released in 110 days from thinner rods and in 150 days from thicker rods. Drug release comprised a starting peak, slow release phase, then a high release phase, and a burst release phase. DSC analysis showed that DS containing rods had crystallinity in their structure. In conclusions, it is feasible to combine PLGA 80/20 and DS by using melt extrusion. Released DS concentrations reached local therapeutic levels, but the release profile was complex and therapeutic levels were not reached all the time.

Comparative toxicity studies in birds using nimesulide and diclofenac sodium

Nimesulide, a sulfonanilide derivative, was compared with diclofenac sodium for toxicity in poultry. In this study, Vanaraja and PB1 birds of 6 weeks old (either sex) were mixed and equally divided into 5 groups of 10 birds each. The birds were inoculated with nimesulide, @ 5 and 2mg; vehicle @ 0.5ml; and diclofenac sodium @ 5mg on kg bwt basis. One group served as untreated control. All the groups were observed for a period of 28days. Forty percent mortality was observed within 12 days in diclofenac-treated group. While birds inoculated with nimesulide remained normal. No significant differences in the weight gain, haematology, total protein contents in the nimesulide and diclofenac groups (survived birds) were observed when compared with the control group of birds. Serum creatinine, cholesterol, alkaline phosphatase, and aspartate aminotransferase levels were significantly (P<0.05) high in diclofenac-treated group compared to nimesulide (P>0.05) and control groups. Nimesulide-treated groups did not show any histopathological lesions, where as diclofenac-treated birds showed histopathological lesions in liver and kidney.

Analgesic, antiinflammatory and hypoglycaemic effects of ethanol extract of Zingiber officinale (Roscoe) rhizomes (Zingiberaceae) in mice and rats

The present study was undertaken to investigate the analgesic, antiinflammatory and hypoglycaemic effects of Zingiber officinale dried rhizomes ethanol extract (ZOE) in mice and rats. The analgesic effect of ZOE was evaluated by 'hot-plate' and 'acetic acid' analgesic test methods in mice; while the antiinflammatory and hypoglycaemic effects of the plant extract were investigated in rats, using fresh egg albumin-induced pedal oedema, and streptozotocin (STZ)-induced diabetes mellitus models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. ZOE (50-800 mg/kg i.p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced nociceptive pain in mice. The plant extract (ZOE, 50-800 mg/kg p.o.) also significantly (p < 0.05-0.001) inhibited fresh egg albumin-induced acute inflammation, and caused dose-related, significant (p < 0.05-0.001) hypoglycaemia in normal (normoglycaemic) and diabetic rats. The findings of this experimental animal study indicate that Zingiber officinale rhizomes ethanol extract possesses analgesic, antiinflammatory and hypoglycaemic properties; and thus lend pharmacological support to folkloric, ethnomedical uses of ginger in the treatment and/or management of painful, arthritic inflammatory conditions, as well as in the management and/or control of type 2 diabetes mellitus in some rural Africa communities.

Effects of non-steroidal anti-inflammatory drugs on cell proliferation and death in cultured epiphyseal-articular chondrocytes of fetal rats

Previous reports indicated that non-steroidal anti-inflammatory drugs (NSAIDs) suppress bone repair. Our previous study further found that ketorolac delayed the endochondral bone formation, and the critical effective timing was at the early stage of repair. Furthermore, we found that NSAIDs suppressed proliferation and induced cell death of cultured osteoblasts. In this study, we hypothesized that chondrocytic proliferation and death, which plays an important role at the early stage of endochondral bone formation, might be affected by NSAIDs. Non-selective NSAIDs, indomethacin, ketorolac, diclofenac and piroxicam; cyclooxygenase-2 (COX-2) selective NSAIDs, celecoxib and DFU (an analog of rofecoxib); prostaglandins (PGs), PGE1, PGE2 and PGF2alpha; and each NSAID plus each PG were tested. The effects of NSAIDs on proliferation, cell cycle kinetics, cytotoxicity and cell death of epiphyseal-articular chondrocytes of fetal rats were examined. The results showed that all the tested NSAIDs, except DFU, inhibited thymidine incorporation of chondrocytes at a concentration range (10(-8) to 10(-4)M) covering the theoretic therapeutic concentrations. Cell cycle was arrested by NSAIDs at the G(0)/G(1) phase. Upon a 24h treatment, LDH leakage and cell death (both apoptosis and necrosis) were significantly induced by the four non-selective NSAIDs in chondrocyte cultures. However, COX-2 inhibitors revealed non-significant effects on cytotoxicity of chondrocytes except higher concentration of celecoxib (10(-4)M). Replenishments of PGE1, PGE2 or PGF2alpha could not reverse the effects of NSAIDs on chondrocytic proliferation and cytotoxicity. In this study, we found that therapeutic concentrations of non-selective NSAIDs caused proliferation suppression and cell death of chondrocytes, suggesting these adverse effects may be one of the reasons that NSAIDs delay the endochondral ossification during bone repair found in previous studies. Furthermore, these effects of NSAIDs may act via PG-independent mechanisms. COX-2 selective NSAIDs showed less deleterious effects on chondrocytic proliferation and death.

The non-steroidal anti-inflammatory drug, diclofenac, inhibits Na+ current in rat myoblasts

The inhibitory effect of diclofenac, a non-steroidal anti-inflammatory drug (NSAID), on the voltage-gated inward Na+ current (I(Na)) in cultured rat myoblasts was investigated using the whole-cell voltage-clamp technique. At concentrations of 10 nM-100 microM, diclofenac produced a dose-dependent and reversible inhibition of I(Na) with an IC50 of 8.51 microM, without modulating the fast activation and inactivation process. The inhibitory effect of diclofenac took place at resting channels and increased with more depolarizing holding potential. In addition to inhibiting the Na+ current amplitude, diclofenac significantly modulated the steady-state inactivation properties of the Na+ channels, but did not alter the steady-state activation. The steady-state inactivation curve was significantly shifted towards the hyperpolarizing potential in the presence of diclofenac. Furthermore, diclofenac treatment resulted in a fairly slow recovery from inactivation of the Na+ channel. The inhibitory effect of diclofenac was enhanced by repetitive pulses and was inflected by changing frequency; the blocking effect at higher frequency was significantly greater than at lower frequency. Both intracellular and extracellular application of diclofenac could inhibit I(Na), indicating that diclofenac may exert its channel inhibitory action both inside and outside the channel sites. Our data directly demonstrate that diclofenac can inhibit the inward Na+ channels in rat myoblasts. Some different inhibitory mechanisms from that in neuronal Na+ channels are discussed.

Pharmacokinetics of diclofenac in sheep following intravenous and intramuscular administration

OBJECTIVES

The aim of this work was to examine the pharmacokinetics of diclofenac (DCLF) in sheep after intravenous (IV) and intramuscular (IM) dosing.

ANIMALS

Healthy male Najdi sheep.

MATERIALS AND METHODS

Diclofenac (1 mg kg(-1)) was administered to ten clinically healthy-male Najdi sheep IV or IM (n = 5 each). Blood samples (5 mL) were collected and serum was separated for drug analysis by high-performance liquid chromatography with UV detection. Diclofenac pharmacokinetic parameters were determined by noncompartmental analysis.

RESULTS

Diclofenac is quickly eliminated from sheep with a terminal T(1/2lambda) of 2-3 hours for both routes of administration. Total DCLF clearance after IV and IM administration was 87.86 +/- 24.10 and 85.69 +/- 40.76 mL kg(-1) hour(-1) respectively. The absolute bioavailability of IM DCLF appears to be approximately 100%.

CONCLUSIONS AND CLINICAL RELEVANCE

The drug should be administered two to three times daily in sheep by IM or IV injection to maintain therapeutic concentrations. Additional studies are needed to evaluate the route of elimination of DCLF in sheep including metabolites formation and the significance of enterohepatic circulation.

Efficacy and tolerability of diclofenac potassium sachets in migraine: a randomized, double-blind, cross-over study in comparison with diclofenac potassium tablets and placebo

A randomized, controlled, cross-over trial compared single doses of 50 mg diclofenac potassium sachets and tablets with placebo in 328 patients with migraine pain, treating 888 attacks. For the primary endpoint 24.7% of the patients were pain free at 2 h postdose with sachets, 18.5% for tablets and 11.7% for placebo. Treatment differences were significant for sachets vs. placebo (P<0.0001), tablets vs. placebo (P=0.0040) and for sachets vs. tablets (P=0.0035). The numbers needed to treat compared with placebo to achieve pain free at 2 h were 7.75 [95% confidence interval (CI) 5.46, 13.35] for sachets and 15.83 (95% CI 8.63, 96.20) for tablets. Sachets were also statistically superior to tablets for sustained headache response, sustained pain free and reduction in headache intensity within the first 2 h postdose measured on a visual analogue scale (P<0.05). Onset of analgesic effect was 15 min for sachets and 60 min for tablets. Fewer patients needed rescue medication, and there were marked improvements in accompanying symptoms and working ability with both sachets and tablets vs. placebo. No safety issues were identified. This study demonstrates that sachets offer patients suffering from migraine pain a more effective treatment with a faster onset of analgesia when compared with tablets.

Diclofenac sodium in the treatment of osteoarthritis

Diclofenac is a well-tolerated, traditional nonsteroidal anti-inflammatory drug that has been shown to be very effective for the treatment of osteoarthritis. Serendipitously, diclofenac has been shown to be relatively selective for cyclooxygenase-2; perhaps due to that fact, it has proven to be well tolerated. Tolerance and utility have been augmented with a variety of formulations, including extended-release tablets, a combination tablet with misoprostol, a suppository preparation and a topically absorbed solution. Sodium diclofenac tablets are available in 25 and 50 mg units, the extended-release tablets are available in 75 and 100 mg units, and the suppositories in 50 and 100 mg units. The usual daily dose ranges from 75 to 150 mg, ingested as two or three divided doses. The drug is a phenylacetic acid derivative. Although it is completely absorbed, only 60% is thought to reach the systemic circulation due to first-pass metabolism. The area under the plasma concentration curve is proportional to the dose in the range of 25–150 mg.

Efficacy and tolerability of diclofenac potassium sachets in acute postoperative dental pain: a placebo-controlled, randomised, comparative study vs. diclofenac potassium tablets

This double-blind, randomised, parallel-group trial compared the analgesic efficacy of single 50 mg doses of diclofenac potassium sachets and tablets with placebo in 184 patients with moderate/severe pain after third molar extraction. The primary efficacy variable was the average pain reduction from baseline during the first 2-h postdose, using a visual analogue scale (VAS). During the first 2-h postdose, sachets and tablets significantly reduced pain (p < 0.05) vs. placebo with an incremental benefit seen for sachets over tablets (p < 0.05). Onset of analgesic effect (VAS) was at 30 min for sachets and 45 min for tablets. Pain reduction vs. placebo (VAS) was maintained for 8 h for sachets and tablets (p < 0.05). VAS-findings were confirmed by pain relief and intensity verbal scale assessments. Fewer patients re-medicated vs. placebo. No safety issues were identified. This study demonstrates that both diclofenac potassium sachets and tablets offer patients suffering from acute pain conditions an effective treatment with incremental analgesic benefits seen for sachets.

Antinociceptive, anti-inflammatory and antidiabetic properties of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm ['African Potato'] aqueous extract in mice and rats

In order to scientifically appraise some of the anecdotal, folkloric, ethnomedical uses of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm ['African Potato'], the present study was undertaken to examine the antinociceptive, anti-inflammatory and antidiabetic properties of the corm's aqueous extract (APE) in mice and rats. The antinociceptive effect of APE was evaluated by 'hot-plate' and 'acetic acid' analgesic test methods in mice; while the anti-inflammatory and antidiabetic effects of the plant's extract were investigated in rats, using fresh egg albumin-induced pedal (paw) oedema, and streptozotocin (STZ)-induced diabetes mellitus models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. H. hemerocallidea corm aqueous extract (APE, 50-800 mg/kg i.p.) produced dose-dependent, significant (P < 0.05-0.001) antinociceptive effects against thermally- and chemically-induced nociceptive pain stimuli in mice. The plant extract (APE, 50-800 mg/kg p.o.) also significantly (P < 0.05-0.001) inhibited fresh egg albumin-induced acute inflammation, and caused dose-related, significant (P < 0.05-0.001) hypoglycaemia in normal (normoglycaemic) and diabetic rats. The results obtained in this study suggest that the antinociceptive effects of the plant's extract are peripherally- and centrally-mediated. The findings of this experimental animal study indicate that H. hemerocallidea corm aqueous extract (APE) possesses antinociceptive, anti-inflammatory and antidiabetic properties; and thus lend pharmacological support to folkloric, anecdotal uses of 'African Potato' in the treatment and/or management of painful, arthritic inflammatory conditions, as well as in the management and/or control of type-2 diabetes mellitus in some parts of southern Africa.

Effects of ultrasound and diclofenac phonophoresis on inflammatory pain relief: suppression of inducible nitric oxide synthase in arthritic rats

BACKGROUND AND PURPOSE

The direct effects of ultrasound (US) and phonophoresis of a nonsteroidal anti-inflammatory drug (NSAID) on injured peripheral tissue have been widely investigated, but evidence concerning the effects of central spinal nociceptive modulation seems to be lacking. The purpose of this study was to investigate the peripheral influences of US and phonophoresis on the modulation of spinal inducible nitric oxide synthase (iNOS) expression elicited by hind paw stimulation with an ankle injection of complete Freund adjuvant (CFA).

SUBJECTS AND METHODS

Inflammatory arthritis was induced in 18 male Wistar rats with intra-articular tibiotarsal injections of CFA. Serial changes in inflammatory pain reactions, including hind-limb edema, and the locomotor activity of the arthritic animals were measured. Arthritic rats underwent US (n=6), diclofenac phonophoresis (n=6), or sham treatment (n=6) on the CFA-injected leg at 18 hours after injection. At 20 hours after injection, spinal inducible nitric oxide synthase-like immunoreactive (iNOS-LI) cells were examined.

RESULTS

Following the CFA injection, all animals' paw diameters and ankle circumferences ipsilateral to the injected leg were significantly increased compared with the values prior to injection. The rearing behavior of arthritic animals had improved significantly after US and diclofenac phonophoresis treatments. The mean total number (+/-SD) of iNOS-LI cells per section of segments L1 and L2 of the bilateral spinal cord of the sham treatment, US, and phonophoresis groups were 531.20+/-6.11, 124.20+/-4.09, and 114.80+/-3.23, respectively. The total numbers of iNOS-LI cells in rats treated with US and diclofenac phonophoresis were significantly smaller than in those receiving sham treatment. There were no significant differences in the total number of iNOS-LI cells ipsilateral to the injected leg between the US and diclofenac phonophoresis groups.

DISCUSSION AND CONCLUSION

Ultrasound and phonophoresis treatments probably modulate and prevent the CFA-insult-induced increase in total and regional iNOS-LI neurons. Peripheral use of diclofenac phonophoresis offers little advantage over US alone in affecting the central mechanisms of nociception. The peripheral influences of US and phonophoresis on the central modulation of the spinal nociceptive processing system are important and may reflect the work being done through the neuroplasticity of spinal cord in response to peripheral input of US and phonophoresis.

Losartan attenuates the antimigratory effect of diclofenac in spontaneously hypertensive rats

Many patients with hypertension, particularly elderly patients, take nonsteroidal antiinflammatory drugs (NSAIDs) and antihypertensive agents. However, few studies describe the effect of the association of antihypertensive agents with NSAIDs on inflammatory response in hypertension. To investigate this, spontaneously hypertensive rats (SHRs) were treated with either diclofenac alone or diclofenac combined with losartan (an AT1 angiotensin II antagonist). The leukocyte-endothelial interaction was then observed using intravital microscopy. Blood pressure of SHR (169.6+/-3.6) was increased by diclofenac (186.4+/-2.9), reduced by losartan (152.6+/-3.5), and reduced by the combination of the 2 (158.9+/-3.7). All the treatments tested reduced the number of rollers, adherent and migrated leukocytes, and the expression of endothelial intercellular adhesion molecule-1 and P-selectin. The association of losartan reduced the effect of diclofenac on leukocyte migration. Neither treatment tested increased the venular shear rate or modified the venular diameters, number of circulating leukocytes, and L-selectin expression on granulocytes. The reduction of CD11/CD18 expression induced by diclofenac alone was hindered by losartan. A pharmacokinetic interference between losartan and diclofenac was ruled out since no significant differences were observed in the plasma concentrations of each drug when they were associated. In conclusion, although diclofenac does not interfere with the losartan antihypertensive effect, losartan attenuates the effect of diclofenac has on leukocyte behavior and expression of adhesion molecules. Losartan has an antimigratory effect, reducing leukocyte migration by reducing ICAM-1 and P-selectin expression. Losartan may hinder the full expression of the antimigratory effect of diclofenac.

Diclofenac, a nonsteroidal anti-inflammatory drug, activates the transient outward K+ current in rat cerebellar granule cells

Diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), has been widely investigated in terms of its pharmacological action, but less is known about its direct effect on ion channels. Here, the effect of diclofenac on voltage-dependent transient outward K+ currents (I(A)) in cultured rat cerebellar granule cells was investigated using the whole-cell voltage-clamp technique. At concentrations of 10(-5)-10(-3) M, diclofenac reversibly increased the I(A) amplitude in a dose-dependent manner and significantly modulated the steady-state inactivation properties of the I(A) channels, but did not alter the steady-state activation properties. Furthermore, diclofenac treatment resulted in a slightly accelerated recovery from I(A) channel inactivation. Intracellular application of diclofenac could mimic the effects induced by extracellular application, although once the intracellular response reached a plateau, extracellular application of diclofenac could induce further increases in the current. These observations indicate that diclofenac might exert its effects on the channel protein at both the inner and outer sides of the cell membrane. Our data provide the first evidence that diclofenac is able to activate transient outward potassium channels in neurons. Although further work will be necessary to define the exact mechanism of diclofenac-induced I(A) channel activation, this study provides evidence that the nonsteroidal anti-inflammatory drug, diclofenac, may play a novel neuronal role that is worthy of future study.

Antinociceptive, anti-inflammatory and antidiabetic effects of Bryophyllum pinnatum (Crassulaceae) leaf aqueous extract

In order to scientifically appraise some of the ethnomedical uses of Bryophyllum pinnatum leaves, the present study was undertaken to investigate the antinociceptive, anti-inflammatory and antidiabetic properties of the plant's leaf aqueous extract in experimental animal models. The antinociceptive effect of the herb's leaf extract was evaluated by the 'hot-plate' and 'acetic acid' test models of pain in mice. The anti-inflammatory and antidiabetic effects of the plant's extract were investigated in rats, using fresh egg albumin-induced pedal (paw) oedema, and streptozotocin (STZ)-induced diabetes mellitus. Diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used respectively as reference drugs for comparison. Bryophyllum pinnatum leaf aqueous extract (BPE, 25-800 mg/kg i.p.) produced significant (P<0.05-0.001) antinociceptive effects against thermally- and chemically-induced nociceptive pain stimuli in mice. The plant extract (BPE, 25-800 mg/kg p.o. or i.p.) also significantly (P<0.05-0.001) inhibited fresh egg albumin-induced acute inflammation and caused significant (P<0.05-0.001) hypoglycaemia in rats. The results of this experimental animal study suggest that Bryophyllum pinnatum leaf aqueous extract possesses antinociceptive, anti-inflammatory and hypoglycaemic properties. The different flavonoids, polyphenols, triterpenoids and other chemical constituents of the herb are speculated to account for the observed antinociceptive, anti-inflammatory and antidiabetic properties of the plant.

Diclofenac sodium multisource prolonged release tablets—a comparative study on the dissolution profiles

The aim of this work was to compare the dissolution behaviour of six diclofenac sodium prolonged release tablets of different brands obtained from the national market. The formulations contain the same amount of drug substance but different types and/or amount of excipients. The influence of these differences in formulation on the release characteristics of the dosage forms was evaluated on the European Pharmacopoeia apparatus 2 (paddle) employing eight different dissolution media in the pH range 1.2-8. Friability and hardness were tested too according to the European Pharmacopoeia. Dissolution profiles obtained from the studied formulations showed that the release characteristics vary considerably among different manufacturers and that even identical formulations show rather dissimilar release profiles in all the studied media. Use of both SIF without pancreatin and SIF without pancreatin containing 1% (w/v) Tween 20 resulted in strong discrimination among products. A correlation between friability and hardness and in vitro dissolution was evidenced for two formulations having identical excipient composition.

Application of experimental design methodology in development and optimization of drug release method

The aim of our research was to apply experimental design methodology in the development and optimization of drug release methods. Diclofenac sodium (2-[(2,6-dichlorophenyl)amino]benzeneacetic acid monosodium salt) was selected as a model drug and Naklofen retard prolonged release tablets, containing 100 mg of diclofenac sodium, were chosen as a model prolonged release system. On the basis of previous results, a three-level three-factorial Box-Behnken experimental design was used to characterize and optimize three physicochemical parameters, i.e. rotation speeds of the stirring elements, pH, and ionic strengths of the dissolution medium, affecting the release of diclofenac sodium from the tablets. The chosen dependent variables (responses) were a cumulative percentage of dissolved diclofenac sodium in 2, 6, 12 and 24 h. For estimation of coefficients in the approximating polynomial function, the least square regression method was applied. Afterwards, the information about the model reliability was verified by using the analysis of variance (ANOVA). The estimation of model factors' significance was performed by Student's t-test. For investigation of the shape of the predicted response surfaces and for model optimization, the canonical analysis was applied. Our study proved that experimental design methodology could efficiently be applied for characterization and optimization of analytical parameters affecting drug release and that it is an economical way of obtaining the maximum amount of information in a short period of time and with the fewest number of experiments.

Comparison of the effect of diclofenac with hyoscine-N-butylbromide in the symptomatic treatment of acute biliary colic

BACKGROUND

Although non-steroidal anti-inflammatory drugs (NSAID) and spasmolytics have been used to relieve biliary colic, the role of these drugs in the natural history of biliary colic has not been clarified. The objective of the present study is to compare the efficacy of intramuscular diclofenac with intramuscular hyoscine in the treatment of pain of acute biliary colic, and to study their role in the natural history of biliary colic and in the prevention of cholelithiasis-related complications.

METHODS

Seventy-two consecutive patients with biliary colic were enrolled in this prospective, randomized, double-blind study. They received either a single 75 mg intramuscular dose of diclofenac (n = 36) or similarly administered 20 mg of hyoscine (n = 36). Pain severity was recorded on a visual analogue scale 30 min, 1 h, 2 h and 4 h after injection of the drug. Patients were then followed closely for the next 72 h for persistence or relapse of pain, or development of acute cholecystitis, or drug related complications.

RESULTS

Diclofenac provided much more rapid relief of pain than hyoscine, as shown by significantly lesser pain scores after injection of the drug. 91.7% of patients on diclofenac were completely relieved of pain at 4 h as compared to 69.4% with hyoscine (P = 0.037). Progression to acute cholecystitis was seen in only 16.66% of patients on diclofenac as compared to 52.77% on hyoscine (P = 0.003).

CONCLUSIONS

In patients with biliary colic, diclofenac gives much faster and more effective pain relief in a significantly larger number of patients as compared with hyoscine. Most remarkably, diclofenac can prevent progression of biliary colic to acute cholecystitis in a significant number of patients.