Celecoxib is as efficacious as naproxen in the management of acute shoulder pain

The effect of experimental shoulder pain on contralateral muscle force and activation

Inhibition of rotator cuff activation and force after local experimental pain has been previously shown. Clinically, strength is often indexed to the uninvolved side in order to quantify deficits during injury and recovery. This study assessed the effect of experimental subacromial pain on contralateral shoulder external rotation (ER) force and activation. We hypothesized that subacromial pain would not affect contralateral shoulder external rotation force and voluntary activation (VA) of the contralateral infraspinatus because we believe that the effects of acute experimental pain will largely exert an ipsilateral, spinal segmental effect. Twenty healthy adults were tested. External rotation force and VA were tested while participants performed maximum voluntary isometric contractions of shoulder external rotation, during which a brief electrical stimulus was applied to the infraspinatus muscle at an intensity that maximized external rotation force. To elicit pain, 1.5 ml of 5% hypertonic saline was injected into the contralateral subacromial space. Mean (SD) pain immediately after injection was 6.3/10 (0.85) resulting in a 7.6% decline in contralateral external rotation force (p < .01) and 3.3% decline in infraspinatus muscle VA (p = .48). A subset of participants (n = 9) showed a more substantial decline in both force (15.4%; p < .000001; d = -3.53) and VA (8.7%; p = .045; d = -0.98). Experimental shoulder pain had a modest effect on contralateral ER force and VA in a subset of participants; therefore, it may be important to index or compare strength bilaterally throughout rehabilitation to capture this bilateral effect as pain resolves.

Gellan gum macrobeads loaded with naproxen: The impact of various naturally derived polymers on pH-dependent behavior

Aims

After oral administration, naproxen generates several side-effects related to stomach malfunction. Undoubtedly, the enteric dosage forms with naproxen can be considered as safer. Moreover, since it has been evidenced that development and growth of colorectal cancer is related to the presence of cyclooxygenase, naproxen is investigated in terms of the tumor prevention. The aim of the present work was to formulate and evaluate the properties of novel naproxen-loaded macrobeads, made on the basis of low-acyl gellan gum and its blends with carrageenans, guar gum, cellulose sulfate, and dextran sulfates.

Method

Seven formulations were prepared by ionotropic gelation. The morphology of the dried beads was evaluated by scanning electron microscopy. The next step focused on Raman spectroscopy and thermal analysis of naproxen, polymers, and the beads. Next, the swelling behavior was examined in three acceptor fluids at pH = 1.2; 4.5, and 7.4. The beads were evaluated regarding naproxen content and encapsulation efficiency. The last stage of the work concerned the drug release studies.

Results

Addition of any other polysaccharide than gellan resulted in flattening of the beads upon drying. Differential scanning calorimetry confirmed the crystalline form of naproxen. Raman spectra showed that no apparent interactions occurred. In the acidic environment, all the beads revealed the tendency to absorb water. The beads swelled to the greatest extent at pH = 4.5. Naproxen was released from the beads at a varied rate. At pH = 7.4, the most prolonged release was observed for the beads containing carrageenans.

Conclusions

We have proved that blending of gellan with various polysaccharides can change the pH-dependent properties of the beads loaded with naproxen. We believe that the information enclosed in the paper will be of particular importance regarding the development and characteristics of novel oral dosage forms based on natural polymers.

Is Extracorporeal Shockwave Therapy Combined With Isokinetic Exercise More Effective Than Extracorporeal Shockwave Therapy Alone for Subacromial Impingement Syndrome? A Randomized Clinical Trial

Study Design Single-blind randomized trial. Background Extracorporeal shockwave therapy (ESWT) has been shown to produce good results in the treatment of subacromial impingement syndrome (SAIS). The efficacy of a combined administration of ESWT and isokinetic exercise (IE) has not yet been studied. Objectives To evaluate the efficacy of focused ESWT combined with IE for the rotator cuff versus focused ESWT alone in the treatment of SAIS. The secondary objective was to assess the isokinetic torque recovery (external rotation at 210°/s, 180°/s, and 120°/s). Methods Thirty participants with SAIS were randomly assigned to a focused-ESWT group or focused ESWT-plus-IE group. Subjects of both groups received 3 treatment sessions of focused ESWT over a period of 10 days. Participants in the second group also received IE for 10 therapy sessions. Outcome measures were the Constant-Murley score (CMS), the visual analog scale (VAS), and isokinetic parameters (peak torque and total work calculated from 5 repetitions) measured with the isokinetic test. Subjects were assessed at baseline, 10 days after the last treatment session with focused ESWT, and after 2 months of follow-up. Results At 2 months posttreatment, participants in the focused ESWT-plus-IE group showed significantly less pain (focused-ESWT VAS, 3.4 ± 0.8 versus focused ESWT-plus-IE VAS, 1.5 ± 0.5; P<.001) and greater improvement in functionality (focused-ESWT CMS, 75.9 ± 6.7 versus focused ESWT-plus-IE CMS, 92.1 ± 6.3; P<.001) and muscle endurance than the subjects in the focused-ESWT group. Conclusion In subjects with SAIS, combined administration of focused ESWT and IE for the rotator cuff resulted in greater reduction of pain, as well as superior functional recovery and muscle endurance in the short to medium term, compared with ESWT alone. Level of evidence Therapy, 2b.

TRIAL REGISTRATION

unregistered 2011 trial. J Orthop Sports Phys Ther 2016;46(9):714-725. Epub 5 Aug 2016. doi:10.2519/jospt.2016.4629.

Short-term effects of high-intensity laser therapy, manual therapy, and Kinesio taping in patients with subacromial impingement syndrome

Subacromial impingement syndrome (SAIS) is a major contributing factor of shoulder pain; and treatment approaches (Kinesio® taping [KT], Exercise [EX], manual therapy [MT], and high-intensity laser therapy [HILT]) have been developed to treat the pain. The key objective of this study was to compare the effects of KT, MT, and HILT on the pain, the range of motion (ROM), and the functioning in patients with SAIS. Seventy patients with SAIS were randomly divided into four groups based on the treatment(s) each group received [EX (n = 15), KT + EX (n = 20), MT + KT + EX (n = 16), and MT + KT + HILT + EX (n = 19)]. All the patients were assessed before and at the end of the treatment (15th day). The main outcome assessments included the evaluation of severity of pain by visual analogue scale (VAS) and shoulder flexion, abduction, and external rotation ROM measurements by a universal goniometry. Shoulder pain and disability index (SPADI) was used to measure pain and disability associated with shoulder pathology. Statistically significant differences were found in the treatment results of all parameters in MT + KT + EX and HILT + MT + KT + EX groups (p < 0.05). When the means of ROM and SPADI results of three groups were compared, statistically significant differences were found between all the groups (p < 0.05). These differences were significant especially between the groups MT + KT + EX and KT + EX (p < 0.05) and HILT + MT + KT + EX and KT + EX (p < 0.05). HILT and MT were found to be more effective in minimizing pain and disability and increasing ROM in patients with SAIS. Further studies with follow-up periods are required to determine the advantages of these treatments conclusively.

Gastrointestinal tolerability of diclofenac epolamine topical patch 1.3%: a pooled analysis of 14 clinical studies

OBJECTIVE

The purpose of this investigation was to evaluate the gastrointestinal (GI) tolerability profile of diclofenac epolamine topical patch 1.3% (DETP) during short-term treatment in patients with mild-to-moderate pain.

DESIGN

Fourteen clinical trials of DETP were examined; 10 placebo-controlled studies were further integrated for analyses. All adverse event (AE) data were coded to the Medical Dictionary for Regulatory Activities.

OUTCOME MEASURES

Frequency of GI AEs was summarized by treatment, preferred term, sex, and age group.

RESULTS

The percentage of patients reporting GI AEs were similar between patients treated with the DETP and placebo, with only 3 of the 10 placebo-controlled trials reporting events in >2% of patients; there was no significant difference between DETP and placebo for any preferred GI term. The most common GI AE reported for both treatment groups was nausea (1.5% DETP, 1.1% placebo). There was no significant difference between treatment groups and sex in the number of reported events and no noted difference between age groups.

CONCLUSION

This study provides evidence that DETP is a topical nonsteroidal anti-inflammatory drug that is a well-tolerated treatment option, demonstrating a low incidence of GI AEs across 14 clinical trials, making it a possible alternative to short-term oral NSAIDs, which are commonly associated with GI complications.

Diclofenac epolamine topical patch relieves pain associated with ankle sprain

Background:

Sports-related injuries, such as sprains and strains, commonly occur during exercise and athletic events. Current therapy includes nonsteroidal anti-inflammatory drugs (NSAIDs), which have a high incidence of upper gastrointestinal side effects. The present study assessed the efficacy and safety of the diclofenac epolamine topical patch (DETP, 1.3%), a topical NSAID for the treatment of acute minor sprains and strains.

Methods:

This multicenter, randomized, placebo-controlled clinical study enrolled adult patients (n = 134) with acute ankle pain (due to a minor sprain) occurring less than 48 hours prior to entering the study. Patients were treated with either the DETP or a placebo topical patch daily for seven days. Pain intensity was evaluated during the first six hours after application of the patch, and on treatment days 1, 2, 3, and 7.

Results:

Patients treated with the DETP experienced a significantly greater reduction in pain associated with their ankle injury compared with placebo, beginning four hours after the first patch application (P = 0.02). The DETP was well tolerated and was comparable with placebo in terms of safety.

Conclusion:

Overall, the results of this study demonstrate that the DETP is an effective analgesic for local treatment of pain in mild acute ankle sprain.

Time to significant pain reduction following DETP application vs placebo for acute soft tissue injuries

OBJECTIVE

Nonsteroidal anti-inflammatory drugs (NSAIDs) provide fast and effective acute pain relief, but systemic administration has increased risk for some adverse reactions. The diclofenac epolamine 1.3% topical patch (DETP) is a topical NSAID with demonstrated safety and efficacy in treatment of acute pain from minor soft tissue injuries. Significant pain reduction has been observed in clinical trials within several hours following DETP application, suggesting rapid pain relief; however, this has not been extensively studied for topical NSAIDs in general. This retrospective post-hoc analysis examined time to onset of significant pain reduction after DETP application compared to a placebo patch for patients with mild-to-moderate acute ankle sprain, evaluating the primary efficacy endpoint from two nearly identical studies.

RESEARCH DESIGN AND METHODS

Data from two double-blind, randomized, parallel-group, placebo-controlled studies (N = 274) of safety and efficacy of the DETP applied once daily for 7 days for acute ankle sprain were evaluated post-hoc using statistical modeling to estimate time to onset of significant pain reduction following DETP application.

MAIN OUTCOME MEASURES

Pain on active movement on a 100 mm Visual Analog Scale (VAS) recorded in patient diaries; physician- and patient-assessed tolerability; and adverse events.

RESULTS

DETP treatment resulted in significant pain reduction within approximately 3 hours compared to placebo. Within-treatment post-hoc analysis based on a statistical model suggested significant pain reduction occurred as early as 1.27 hours for the DETP group. The study may have been limited by the retrospective nature of the analyses. In both studies, the DETP was well tolerated with few adverse events, limited primarily to application site skin reactions.

CONCLUSION

The DETP is an effective treatment for acute minor soft tissue injury, providing pain relief as rapidly as 1.27 hours post-treatment. Statistical modeling may be useful in estimating time to onset of pain relief for comparison of topical and oral NSAIDs.

Efficacy and Safety of Celecoxib in the Treatment of Acute Pain due to Ankle Sprain in a Latin American and Middle Eastern Population

Ankle sprains are common acute soft-tissue injuries. This 7-day open-label, multicentre, randomized study compared the efficacy and safety of celecoxib with non-selective non-steroidal antiinflammatory drugs (NSAIDs) in treating acute ankle sprain with moderate-to-severe ankle pain in 278 patients. Patients received either celecoxib (400 mg loading dose followed by 200 mg twice daily) or standard doses of non-selective NSAIDs. The primary endpoint was a change in the patient's assessment of ankle pain on a 0 mm (no pain) −100 mm (worst possible pain) visual analogue scale (VAS) at day 3 compared with baseline. From a baseline of 73 mm, mean VAS pain scores decreased to 29 and 32 mm in the celecoxib and non-selective NSAID groups, respectively. The lower limit of the 95% confidence interval for the treatment difference with regard to change from baseline was greater than the pre-established non-inferiority margin of −10 mm. Using an initial loading dose, celecoxib was at least as efficacious as non-selective NSAIDs in treating acute pain due to ankle sprain.

Celecoxib in the treatment of primary dysmenorrhea: results from two randomized, double-blind, active- and placebo-controlled, crossover studies

BACKGROUND

Celecoxib, a cyclooxygenase-2 inhibitor, has established analgesic efficacy for the treatment of acute pain resulting from a variety of causes.

OBJECTIVE

This article describes 2 studies designed to assess the efficacy and tolerability of celecoxib in patients with primary dysmenorrhea.

METHODS

Two identical, 3-day, multiple-dose, randomized, double-blind, active- and placebo-controlled, crossover studies were carried out in women aged 18 to 44 years with primary dysmenorrhea (studies 1 and 2). The studies employed a 6-sequence, 3-period, complete-block crossover design over 3 menstrual cycles. Patients received celecoxib 400 mg, followed by celecoxib 200 mg no sooner than 12 hours after first dose (day 1), then celecoxib 200 mg q12h as necessary (days 2 and 3); naproxen sodium 550 mg followed by naproxen sodium 550 mg no sooner than 12 hours after first dose (day 1), then naproxen sodium 550 mg q12h as necessary (days 2 and 3); or placebo. Primary efficacy measures were time-weighted sum of total pain relief and time-weighted sum of pain intensity difference at 8 hours after administration of the first dose of study medication (TOTPAR[8] and SPID[8], respectively). Tolerability was assessed using routine physical examination, including vital sign measurements, and clinical laboratory analyses at screening and end of study.

RESULTS

In total, 149 and 154 patients were randomized to 1 of the 6 treatment sequences in studies 1 and 2, respectively. Across treatment sequences, mean age ranges were 23.4 to 26.9 years (study 1) and 28.3 to 34.1 years (study 2). Mean weight ranges were 62.7 to 74.5 kg (study 1) and 69.2 to 86.7 kg (study 2). Most patients (96.6% in study 1, 80.5% in study 2) were white. Mean TOTPAR[8] values with celecoxib (study 1/study 2, 18.28/17.98) and naproxen sodium (20.59/21.27) were significantly greater than with placebo (12.82/12.98) (all, P < 0.001). Mean SPID[8] values were significantly greater with celecoxib (10.06/9.60) and naproxen sodium (11.48/11.71) than with placebo (5.96/6.41) (all, P < 0.001). Naproxen sodium was significantly different from celecoxib in TOTPAR[8] (study 2 only) and SPID[8] (both studies) (all, P < 0.001). In both studies, the adverse-events (AEs) profile was not significantly different between treatments, with the majority of AEs being related to primary dysmenorrhea and not medication. Less than 10% of patients experienced severe AEs in any treatment period.

CONCLUSIONS

In these 2 identically designed studies in women aged 18 to 44 years, celecoxib 400 mg (followed by 200 mg q12h) was more effective, as measured using pain scores, in the treatment of primary dysmenorrhea compared with placebo. In each study, the primary efficacy measures-TOTPAR[8] and SPID[8] scores-were significantly improved with celecoxib and naproxen sodium compared with placebo. SPID[8] in both studies and TOTPAR[8] in study 2 were significantly improved with naproxen sodium compared with celecoxib. Both celecoxib and naproxen sodium were well tolerated and provided relief from menstrual pain within 1 hour of administration.

Short-term effects of high-intensity laser therapy versus ultrasound therapy in the treatment of people with subacromial impingement syndrome: a randomized clinical trial

BACKGROUND

Subacromial impingement syndrome (SAIS) is a painful condition resulting from the entrapment of anatomical structures between the anteroinferior corner of the acromion and the greater tuberosity of the humerus.

OBJECTIVE

The aim of this study was to evaluate the short-term effectiveness of high-intensity laser therapy (HILT) versus ultrasound (US) therapy in the treatment of SAIS.

DESIGN

The study was designed as a randomized clinical trial.

SETTING

The study was conducted in a university hospital.

PATIENTS

Seventy patients with SAIS were randomly assigned to a HILT group or a US therapy group.

INTERVENTION

Study participants received 10 treatment sessions of HILT or US therapy over a period of 2 consecutive weeks.

MEASUREMENTS

Outcome measures were the Constant-Murley Scale (CMS), a visual analog scale (VAS), and the Simple Shoulder Test (SST).

RESULTS

For the 70 study participants (42 women and 28 men; mean [SD] age=54.1 years [9.0]; mean [SD] VAS score at baseline=6.4 [1.7]), there were no between-group differences at baseline in VAS, CMS, and SST scores. At the end of the 2-week intervention, participants in the HILT group showed a significantly greater decrease in pain than participants in the US therapy group. Statistically significant differences in change in pain, articular movement, functionality, and muscle strength (force-generating capacity) (VAS, CMS, and SST scores) were observed after 10 treatment sessions from the baseline for participants in the HILT group compared with participants in the US therapy group. In particular, only the difference in change of VAS score between groups (1.65 points) surpassed the accepted minimal clinically important difference for this tool.

LIMITATIONS

This study was limited by sample size, lack of a control or placebo group, and follow-up period.

CONCLUSIONS

Participants diagnosed with SAIS showed greater reduction in pain and improvement in articular movement functionality and muscle strength of the affected shoulder after 10 treatment sessions of HILT than did participants receiving US therapy over a period of 2 consecutive weeks.

A randomised, double-blind study comparing lumiracoxib with naproxen for acute musculoskeletal pain

BACKGROUND

Some selective cyclooxygenase-2 (COX-2) inhibitors have been shown to provide analgesic efficacy in patients with acute pain.

AIM

To compare the efficacy and safety of the COX-2 inhibitor lumiracoxib 400 mg once daily (qd) and naproxen 500 mg twice daily (bid) in patients with acute musculoskeletal pain caused by uncomplicated soft tissue injury.

METHODS

This was a randomised, double-blind, parallel-group, non-inferiority study set in 39 primary care centres in the UK. Patients were randomised to lumiracoxib 400 mg qd or naproxen 500 mg bid and took the study medication for as long as they felt that it was needed, up to day 7. The primary efficacy analysis was the sum of the pain intensity difference (0-100 mm visual analogue scale) determined morning and evening over the first 5 days of treatment (SPID-5).

RESULTS

The intention-to-treat population comprised 406 patients [lumiracoxib 400 mg qd (n = 207); naproxen 500 mg bid (n = 199)]. Both treatments were effective in reducing pain intensity over 5 days. The mean SPID-5 scores were 117.0 mm.day for lumiracoxib and 118.2 mm.day for naproxen [the treatment difference based on adjusted means from the ANCOVA was -2.78 mm.day, 95% confidence interval (CI) -17.4, 11.9]. The lower margin of the 95% CI was above the predetermined non-inferiority margin (-50 mm.day) for SPID-5, indicating non-inferiority of lumiracoxib compared with naproxen. Both treatments were well tolerated.

CONCLUSION

Lumiracoxib 400 mg qd is as effective as naproxen 500 mg bid for the management of moderate-to-severe acute musculoskeletal pain.

Clinical use and pharmacological properties of selective COX-2 inhibitors

Selective COX-2 inhibitors (coxibs) are approved for the relief of acute pain and symptoms of chronic inflammatory conditions such as osteoarthritis (OA) and rheumatoid arthritis (RA). They have similar pharmacological properties but a slightly improved gastrointestinal (GI) safety profile if compared to traditional nonsteroidal anti-inflammatory drugs (tNSAIDs). However, long-term use of coxibs can be associated with an increased risk for cardiovascular (CV) adverse events (AEs). For this reason, two coxibs were withdrawn from the market. Currently celecoxib, etoricoxib, and lumiracoxib are used. These three coxibs differ in their chemical structure and selectivity for COX-2, which might explain some of their pharmacological features. Following oral administration, the less lipophilic celecoxib has a lower bioavailability (20-40%) than the other two coxibs (74-100%). All are eliminated by hepatic metabolism involving mainly CYP2C9 (celecoxib, lumiracoxib) and CYP3A4 (etoricoxib). Elimination half-life varies from 5 to 8 h (lumiracoxib), 11 to 16 h (celecoxib) and 19 to 32 h (etoricoxib). In patients with liver disease, plasma levels of celecoxib and etoricoxib are increased about two-fold. Clinical efficacies of the coxibs are comparable to tNSAIDs. There is an ongoing discussion about whether the slightly better GI tolerability (which is lost if acetylsalicylic acid is coadministered) of the coxibs is offset by their elevated risks for CV AEs (also seen with tNSAIDs other than naproxen), which apparently increase with dose and duration of exposure. In addition, the higher costs for coxibs (if compared to tNSAIDs, even when a "gastroprotective" proton pump inhibitor is coadministered) should be taken into consideration, if a coxib will be selected for certain patients with a high risk for GI complications. For such treatment, the lowest effective dose should be used for a limited time. Monitoring of kidney function and blood pressure appears advisable. It is hoped that further controlled studies can better define the therapeutic place of the coxibs.

Short-term efficacy of rofecoxib and diclofenac in acute shoulder pain: a placebo-controlled randomized trial

OBJECTIVES

To evaluate the short-term symptomatic efficacy of rofecoxib and diclofenac versus placebo in acute episodes of shoulder pain.

DESIGN

Randomized controlled trial of 7 days.

SETTING

Rheumatologists and/or general practitioners totaling 47.

PARTICIPANTS

Acute shoulder pain.

INTERVENTIONS

Rofecoxib 50 mg once daily, diclofenac 50 mg three times daily, and placebo.

OUTCOME MEASURES

Pain, functional impairment, patient's global assessment of his/her disease activity, and local steroid injection requirement for persistent pain. The primary variable was the Kaplan-Meier estimates of the percentage of patients at day 7 fulfilling the definition of success (improvement in pain intensity and a low pain level sustained to the end of the 7 days of the study; log-rank test).

RESULTS

There was no difference in the baseline characteristics between the three groups (rofecoxib n = 88, placebo n = 94, and diclofenac n = 89). At day 7, the Kaplan-Meier estimates of successful patients was higher in the treatment groups than in the placebo (54%, 56%, and 38% in the diclofenac, rofecoxib, and placebo groups respectively, p = 0.0070 and p = 0.0239 for placebo versus rofecoxib and diclofenac, respectively). During the 7 days of the study, there was a statistically significant difference between placebo and both active arms (rofecoxib and diclofenac) in all the evaluated outcome measures A local steroid injection had to be performed in 33 (35%) and 19 (22%) patients in the placebo and rofecoxib group respectively. Number needed to treat to avoid such rescue therapy was 7 patients (95% confidence interval 5-15).

CONCLUSION

This study highlights the methodological aspects of clinical trials, e.g., eligibility criteria and outcome measures, in acute painful conditions. The data also establish that diclofenac and rofecoxib are effective therapies for the management of acute painful shoulder and that they reduce the requirement for local steroid injection.

Valdecoxib Is as Efficacious as Diclofenac in the Treatment of Acute Low Back Pain

OBJECTIVE

To compare the efficacy of valdecoxib 40 mg q.d. (with a second dose on day 1) with diclofenac 75 mg b.i.d. in the treatment of acute low back pain.

METHODS

This was a multicenter, randomized, double-blind study. Patients with acute low back pain, class 1a or 2a (Quebec Task Force), with a visual analog scale score >/=50 mm (on a 100-mm scale) and moderate to severe pain on a categorical scale, were randomized to valdecoxib 40 mg q.d. (with a second dose on day 1) or diclofenac 75 mg b.i.d. for 7 days (170 patients per group). The primary efficacy end point was change in pain intensity (visual analog scale, mm) from baseline to day 3 for the per-protocol population.

RESULTS

Least squares mean reductions in pain intensity from baseline to day 3 were similar for valdecoxib (-42.02 mm) and diclofenac (-41.43 mm). Valdecoxib was comparable to diclofenac as the lower limit of the 95% confidence interval of the estimated difference (0.59 mm; 95% confidence interval, -3.40 to 4.59 mm) was within the prespecified noninferiority margin of -10 mm. The overall incidence of adverse events was similar for valdecoxib (28%) and diclofenac (26%). No statistically different moderate or severe upper gastrointestinal adverse events were reported, although they were numerically greater for diclofenac (8) than for valdecoxib (3).

DISCUSSION

Valdecoxib 40 mg q.d. (with a second dose on day 1) provides effective relief for acute low back pain, and was at least as efficacious as diclofenac 75 mg b.i.d., with a nonsignificant but numerically lower incidence of gastrointestinal adverse events.

The cyclooxygenase-2 inhibitor GW406381X [2-(4-ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine] is effective in animal models of neuropathic pain and central sensitization

The pathogenic form of the cyclooxygenase (COX) enzyme, COX-2, is also constitutively present in the spinal cord and has been implicated in chronic pain states in rat and man. A number of COX-2 inhibitors, including celecoxib and rofecoxib, are already used in man for the treatment of inflammatory pain. Preclinically, the dual-acting COX-2 inhibitor, GW406381X [2-(4-ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine, where X denotes the free base], is as effective as rofecoxib and celecoxib in the rat established Freund's Complete Adjuvant model with an ED(50) of 1.5 mg/kg p.o. compared with 1.0 mg/kg p.o. for rofecoxib and 6.6 mg/kg p.o. for celecoxib. However, in contrast to celecoxib (5 mg/kg p.o. b.i.d.) and rofecoxib (5 mg/kg p.o. b.i.d.), which were without significant effect, GW406381X (5 mg/kg p.o. b.i.d.) fully reversed mechanical allodynia in the chronic constriction injury model and reversed thermal hyperalgesia in the mouse partial ligation model, both models of neuropathic pain. GW406381X, was also effective in a rat model of capsaicin-induced central sensitization, when given intrathecally (ED(50) = 0.07 mug) and after chronic but not acute oral dosing. Celecoxib and rofecoxib had no effect in this model. Several hypotheses have been proposed to try to explain these differences in efficacy, including central nervous system penetration, enzyme kinetics, and potency. The novel finding of effectiveness of GW406381X in these models of neuropathic pain/central sensitization, in addition to activity in inflammatory pain models and together with its central efficacy, suggests dual activity of GW406381X compared with celecoxib and rofecoxib, which may translate into greater efficacy in a broader spectrum of pain states in the clinic.