Nonsteroid drug selectivities for cyclo-oxygenase-1 rather than cyclo-oxygenase-2 are associated with human gastrointestinal toxicity: a full in vitro analysis

Celecoxib as an in vivo probe of cyclooxygenase-2 mechanisms underlying retrograde amnesia in an animal model of ECT

BACKGROUND

Cyclooxygenase-2 (COX-2) mechanisms are involved in glutamate-mediated learning and memory as well as in glutamatergic excitotoxicity. Electroconvulsive therapy (ECT)-induced amnesia may arise from glutamatergic excitotoxicity; if so, COX-2 inhibition may attenuate retrograde amnesia with ECT.

METHODS

Wistar rats which received celecoxib (15 mg/kg per day) or vehicle for 18 days were trained for 3 days on a passive avoidance task. On each of the next 3 days, rats which showed perfect learning (n=51) received true or sham suprathreshold electroconvulsive shocks (ECS; 60 mC) in a factorial design; daily dosing with drug or vehicle was continued. One day after the last ECS, recall of pre-ECS learning was tested.

RESULTS

ECS-treated rats showed impaired recall in the vehicle but not celecoxib group. Celecoxib significantly protected against ECS-induced retrograde amnesia; this benefit was independent of the drug-induced attenuation of ECS seizure duration.

CONCLUSIONS

Celecoxib may protect against ECS-induced retrograde amnesia by attenuating ECS-induced, COX-2-mediated glutamatergic excitotoxicity.

Peroxisome proliferator-activated receptor-gamma agonist rosiglitazone reverses the adverse effects of diet-induced obesity on oocyte quality

Obesity and its physiological consequences are increasingly prevalent among women of reproductive age and are associated with infertility. To investigate, female mice were fed a high-fat diet until the onset of insulin resistance, followed by assessments of ovarian gene expression, ovulation, fertilization, and oocyte developmental competence. We report defects to ovarian function associated with diet-induced obesity (DIO) that result in poor oocyte quality, subsequently reduced blastocyst survival rates, and abnormal embryonic cellular differentiation. To identify critical cellular mediators of ovarian responses to obesity induced insulin resistance, DIO females were treated for 4 d before mating with an insulin-sensitizing pharmaceutical: glucose and lipid-lowering AMP kinase activator, 5-aminoimidazole 4-carboxamide-riboside, 30 mg/kg.d; sodium salicylate, IkappaK inhibitor that reverses insulin resistance, 50 mg/kg.d; or peroxisome proliferator activated receptor-gamma agonist rosiglitazone, 10 mg/kg.d. 5-aminoimidazole 4-carboxamide-riboside or sodium salicylate treatment did not have significant effects on the reproductive parameters examined. However, embryonic development to the blastocyst stage was significantly improved when DIO mice were treated with rosiglitazone, effectively repairing development rates. Rosiglitazone also normalized DIO-associated abnormal blastomere allocation to the inner cell mass. Such improvements to oocyte quality were coupled with weight loss, improved glucose metabolism, and changes in ovarian mRNA expression of peroxisome proliferator activated receptor-regulated genes, Cd36, Scarb1, and Fabp4 cholesterol transporters. These studies demonstrate that peri-conception treatment with select insulin-sensitizing pharmaceuticals can directly influence ovarian functions and ultimately exert positive effects on oocyte developmental competence. Improved blastocyst quality in obese females treated with rosiglitazone before mating indicates that peroxisome proliferator activated receptor-gamma is a key target for metabolic regulation of ovarian function and oocyte quality.

Celecoxib and ankylosing spondylitis

It is now over 100 years since the arrival of aspirin and, from the mid-20th Century onwards, we have seen numerous attempts at providing society with safer and more efficacious nonsteroidal drugs. Ironically, while aspirin went from strength to strength with an ever-increasing pharmaceutical profile, new nonsteroidal anti-inflammatory drugs arrived and disappeared with rapid succession. Finally, there appears to have been a breakthrough with the development of the coxibs but concern has recently developed because of potential toxic cardiovascular reactions. Although originally studied in rheumatoid arthritis and degenerative arthropathy, the coxibs have now been investigated in ankylosing spondylitis and efficacy appears to be favorable and, to date, there is little evidence of toxicity, although problems in the nonspondylarthropathic arena may spill over into the seronegative spondylarthritides.

Comparative inhibitory activity of etoricoxib, celecoxib, and diclofenac on COX-2 versus COX-1 in healthy subjects

We determined cyclo-oxygenase-1 and cyclo-oxygenase-2 inhibition in healthy middle-aged subjects (41-65 years) randomly assigned to four 7-day treatment sequences of etoricoxib 90 mg every day, celecoxib 200 mg twice a day, diclofenac 75 mg twice a day, or placebo in a double-blind, randomized, 4-period crossover study. Maximum inhibition of thromboxane B(2) (cyclo-oxygenase-1 activity) in clotting whole blood on day 7 (0-24 hours postdose) was the primary endpoint. Inhibition of lipopolysaccharide-induced prostaglandin E(2) in whole blood (cyclo-oxygenase-2 activity) was assessed on day 7 (0-24 hours postdose) as a secondary endpoint. Diclofenac had significantly greater maximum inhibition of thromboxane B(2) versus each comparator (P < .001); placebo 2.4% (95% confidence interval: -8.7% to 12.3%), diclofenac 92.2% (91.4% to 92.9%), etoricoxib 15.5% (6.6% to 23.5%), and celecoxib 20.2% (11.5% to 28.1%). Prostaglandin E(2) synthesis was inhibited with a rank order of potency of diclofenac > etoricoxib > celecoxib. In summary, at doses commonly used in rheumatoid arthritis, diclofenac significantly inhibits both cyclo-oxygenase-1 and cyclo-oxygenase-2, whereas etoricoxib and celecoxib significantly inhibit cyclo-oxygenase-2 and do not substantially inhibit cyclo-oxygenase-1.

Secondary hyperalgesia in the rat first degree burn model is independent of spinal cyclooxygenase and nitric oxide synthase

Various animal models of pain are dependent on activation of different glutamate receptor subtypes. First degree burn of the paw elicits a secondary hyperalgesia that is dependent on Ca2+ permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), but not N-methyl-D-aspartate (NMDA) receptors. The present study takes advantage of that specificity by examining the effects of spinal pretreatments of agents on this secondary hyperalgesia. Rats with indwelling intrathecal catheters were pretreated with agents prior to paw injury. Mechanical withdrawal thresholds were measured before, and for three h after the injury. Spinal pretreatment with cyclooxygenase (10 and 30 microg (S)-(+)-ibuprofen; and 3 and 30 microg ketorolac) and nitric oxide synthase (33 and 100 microg N(G) Nitro-L-arginine methyl ester hydrochloride (L-NAME) and 10 microg thiocitrulline) inhibitors resulted in no specific anti-allodynia. In contrast, ziconotide (0.3, 1.0 and 3 microg), the N-type voltage gated calcium channel antagonist was very effective in blocking burn-induced sensitivity at all doses used. l-type (Diltiazam 230 microg) and P-type (Agatoxin IVA 0.3 microg) calcium channel blockers produced intermediate effects. Thus, cyclooxygenase and nitric oxide synthase are assumed not to be downstream of Ca2+ permeable AMPA receptors. Voltage gated calcium channels blockers could exert their effects either pre- or post-synaptically.

Cyclooxygenase-1-selective inhibitors are attractive candidates for analgesics that do not cause gastric damage. design and in vitro/in vivo evaluation of a benzamide-type cyclooxygenase-1 selective inhibitor

Although cyclooxygenase-1 (COX-1) inhibition is thought to be a major mechanism of gastric damage by nonsteroidal anti-inflammatory drugs (NSAIDs), some COX-1-selective inhibitors exhibit strong analgesic effects without causing gastric damage. However, it is not clear whether their analgesic effects are attributable to COX-1-inhibitory activity or other bioactivities. Here, we report that N-(5-amino-2-pyridinyl)-4-(trifluoromethyl)benzamide ( 18f, TFAP), which has a structure clearly different from those of currently available COX-1-selective inhibitors, is a potent COX-1-selective inhibitor (COX-1 IC 50 = 0.80 +/- 0.05 microM, COX-2 IC 50 = 210 +/- 10 microM). This compound causes little gastric damage in rats even at an oral dose of 300 mg/kg, though it has an analgesic effect at as low a dose as 10 mg/kg. Our results show that COX-1-selective inhibitors can be analgesic agents without causing gastric damage.

The effects of intrathecal cyclooxygenase-1, cyclooxygenase-2, or nonselective inhibitors on pain behavior and spinal Fos-like immunoreactivity

BACKGROUND

Prostaglandins are synthesized by cyclooxygenase (COX) and are thought to play an important role in nociceptive transmission in the spinal cord. Fos expression is an indicator of spinal neuron activation. We examined the role of intrathecal selective and nonspecific COX inhibitors on spinal C-Fos expression.

METHODS

To evaluate the relative contribution of COX-1 and COX-2 in nociceptive transmission in the spinal cord, we assessed the effects of the selective COX-1 inhibitor SC 560, the selective COX-2 inhibitor celecoxib, and the nonselective COX inhibitor ketorolac on formalin-evoked behavior and spinal c-Fos-like immunoreactivity (FLI). Rats received each of the drugs (30, 60, or 90 microg) intrathecally before the subcutaneous administration of formalin (5%, 50 microL) to the plantar surface of a hindpaw. The control group received vehicle intrathecally before the administration of formalin.

RESULTS

Phase 1 flinching behavior decreased in rats given celecoxib or ketorolac 90 mug. Phase 2 flinching behavior decreased in rats given all doses of ketorolac or celecoxib 90 microg (P < 0.05). The FLI was significantly reduced in rats given celecoxib or ketorolac 90 microg for laminae I-II (P < 0.05). By contrast, for laminae V-VI, only the ketorolac 60 or 90 microg treatment group demonstrated a larger decrease in FLI (P < 0.05). The FLI expression in laminae V-VI had a significant correlation with phase 2 flinching behavior (P < 0.05).

CONCLUSIONS

A dual inhibitor of COX-1 and COX-2 suppressed both responses of formalin-evoked behaviors and FLI expression of whole laminae in the lumbar spinal cord. FLI expression of laminae I-II alone may not be a good indicator of the ability to produce anti-hypersensitivity; however, the FLI of laminae V-VI correlates with phase 2 responses.

Eight-week oral administration of meloxicam, a non-steroidal anti-inflammatory drug, prevents dose reduction of pegylated interferon alpha-2a in the treatment of chronic hepatitis C

AIM

We conducted a trial to evaluate whether eight-week oral administration of meloxicam, a non-steroidal anti-inflammatory drug, would decrease the rate of the patients who required dose reduction of pegylated interferon alpha-2a in the treatment of chronic hepatitis C.

METHODS

Sixty patients given weekly subcutaneous administration of pegylated interferon alpha-2a at a dose of 180 mug for 48 weeks were allocated into the meloxicam group (n = 22) and the control group (n = 38) before interferon treatment. Meloxicam was given orally at a dose of 10 mg once a day for eight weeks from the start of interferon treatment.

RESULTS

The cumulative rate of dose-reduction-free patients was significantly higher in the meloxicam group (P < 0.05). Until week eight, 44.7% of the control group and 9.1% of the meloxicam group required dose reduction. Dose was modified by neutropenia in 31.6% and 18.2% of the control and meloxicam groups, respectively. Meloxicam relieved a declineof neutrophil count within the first eight weeks from 54.2% to 44.2% (P < 0.05). Multivariate analysis revealed that greater pretreatment neutrophil count and the use of meloxicam were independent factors associated with avoiding dose reduction. Sustained virological response was obtained in 52.6% of the patients. The multivariate logistic analysis revealed that viral serotype and viral load were the only independent factors associated with sustained virological response.

CONCLUSION

Eight-week administration of meloxicam prevented dose reduction of pegylated interferon by relieving a decline of neutrophil count in the treatment of chronic hepatitis C.

Pharmacological attenuation of electroconvulsive therapy--induced cognitive deficits: theoretical background and clinical findings

Electroconvulsive therapy (ECT) is an effective treatment for depression and other psychiatric disorders. However, the practice of ECT is limited by memory and nonmemory cognitive adverse effects. Technical strategies such as a preference for unilateralover bilateral ECT and low-dose over high-dose stimulation reduce these cognitive adverse effects but may also be associated with lesser treatment efficacy or slower treatment response. This article therefore reviews the use of psychopharmacological agents in the attenuation of ECT-induced cognitive deficits with 2 objectives: the identification of implicated mechanisms and the identification of putative efficacy in both animal and human studies. Drugs examined include N-methyl-d-aspartate receptor antagonists, cyclooxygenase inhibitors, calcium channel blockers, cholinesterase inhibitors, glucocorticoid receptor antagonists, thyroid hormones, opioid antagonists, NO donors, nootropic agents, and other medications. Although the clinical data at present are sparse and inconsistent, many recently opened lines of research improve our understanding of the mechanisms involved as well as suggest possible avenues for the testing of new treatments with the potential to attenuate the cognitive adverse effects of ECT.

The effect of three cyclo-oxygenase inhibitors on intensity of primary dysmenorrheic pain

OBJECTIVE

To determine the effect of 3 different cyclo-oxygenase (COX) inhibitors on primary dysmenorrheic pain.

METHOD

Eleven female patients self-medicated with either placebo (sugar), 25 mg of the COX-2 specific inhibitor rofecoxib, 50 mg of the nonselective COX inhibitor diclofenac potassium, or 7.5 mg of the COX-2 selective inhibitor meloxicam, over 4 menstrual cycles. Pain was assessed using the McGill Pain Questionnaire and a visual analog scale.

RESULTS

The pain response index, present pain index, and visual analog scale were highly correlated as measures of intensity of pain (r=0.81 to 0.96, P<0.0001). Rofecoxib and diclofenac potassium both decreased the duration of dysmenorrheic pain compared with placebo (P<0.001) and with meloxicam (P<0.01), and were equally effective in improving pain, compared with placebo, after each capsule (P<0.001). When compared with placebo, both drugs also provided 50% or more pain relief, after each capsule (P<0.0048). Meloxicam, although superior to placebo, was not as effective as rofecoxib and diclofenac potassium in reducing pain, and when compared with placebo, was associated with providing 50% or more of pain relief only after the third and fourth capsules (P=0.016).

CONCLUSIONS

Rofecoxib and diclofenac potassium, when taken in recommended doses, were equally effective in alleviating pain associated with primary dysmenorrhea.

Clinical safety and efficacy of NG440: a novel combination of rho iso-alpha acids from hops, rosemary, and oleanolic acid for inflammatory conditions

In this report, we examine the clinical safety and efficacy of NG440, a phytochemical-based antiinflammatory formula consisting of a combination of rho iso-alpha acids from hops, rosemary, and oleanolic acid. In a previous study, we demonstrated that NG440 significantly decreased pain by 50% in patients with osteoarthritis. Consistent with these data, results from a multicentre trial indicate that NG440 reduced pain scores in patients with joint discomfort, as measured by VAS (visual analog scale) methodology. As demonstrated in an ex vivo clinical study, these effects on pain relief may be due to reduced inflammatory cytokine production including lower prostaglandin E2 formation. Finally, strong data exist to suggest that NG440 is a safe formula for human consumption. Animal toxicity data revealed no adverse effects of NG440 at dosages < or =250 mg.kg-1.day-1 for 21 days. Furthermore, human trial data suggest that NG440 does not negatively impact cardiovascular and gastrointestinal markers normally affected by selective COX-2 enzyme inhibitors, including platelet function, blood pressure, blood cell count, or fecal calprotectin, a measure of gastrointestinal injury. In conclusion, NG440 may serve as a safe and efficacious alternative in some areas where specific COX-2 inhibitors have been traditionally used.

How readily does ketorolac penetrate cerebrospinal fluid in children?

Ketorolac is a potent nonsteroidal anti-inflammatory analgesic used in postoperative pain management. Ketorolac elicits its analgesic action by inhibiting the cyclo-oxygenase enzyme in peripheral tissues and in the spinal cord. Central nervous system penetration of parenteral ketorolac has been evaluated in adults but not in children. In the present study we investigated ketorolac cerebrospinal fluid penetration via spinal anesthesia in 30 healthy children undergoing surgery in the lower part of the body. A single cerebrospinal fluid and blood sample was obtained between 11 minutes and 6 hours after receiving ketorolac 0.5 mg x kg(-1) IV. Ketorolac concentrations were determined by gas chromatography with mass spectrometric detection. Ketorolac was detected from 22 of the 30 cerebrospinal fluid samples, and the concentrations ranged between 0.2 and 7.6 microg x L(-1) (median, 0.6 microg x L(-1)). The cerebrospinal fluid to unbound plasma concentration-ratio ranged between 0.01 and 0.69 (median, 0.08). These low concentrations indicate that ketorolac does not readily penetrate cerebrospinal fluid in children.

Review: Adverse cardiovascular effects of NSAIDs: driven by blood pressure, or edema?

The non-selective non-steroidal anti-inflammatory drugs (nsNSAIDs) and cyclooxygenase-2 (COX-2) inhibitors are commonly utilized agents for musculoskeletal conditions. The harmful cardiorenal effects of some nsNSAIDs are well described and thought to be related to inhibition of prostanoid synthesis. Since the non-specific inhibition of both cyclooxygenase enzymes was associated with a higher incidence of gastrointestinal side effects, the selective targeting of the COX-2 enzymes with the COX-2 inhibitors promised and delivered a lower incidence of gastrointestinal side effects. However, the COX-2 inhibitors have not been found to be bereft of cardiorenal side effects. Indeed, some of these agents lead to increased blood pressure, an excessive risk of congestive heart failure and pro-thrombotic effects, especially in high risk populations. These deletrious effects, however, may not be class-specific and possibly related to pharmacokinetics, enzyme specificity and endothelium effects. This article also reviews the body of literature linking the nsNSAIDs and COX-2 inhibitors with important adverse cardiorenal effects and their putative mechanisms.

Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) selectivity of COX inhibitors

In vitro evaluations of the selectivity of COX inhibitors are based on a great variety of experimental protocols. As a result, data available on cyclooxygenase (COX)-1/COX-2/5- lipoxygenase (LOX) selectivity of COX inhibitors lack consistency. We, therefore, performed a systematic analysis of the COX-1/COX-2/5-LOX selectivity of 14 compounds with selective COX inhibitory activity (Coxibs). The compounds belonged to different structural classes and were analyzed employing the well-recognized whole-blood assay. 5-LOX activity was also tested on isolated human polymorphonuclear leukocytes. Among COX inhibitors, celecoxib and ML-3000 (licofelone) inhibited 5-LOX in human neutrophils at micromolar ranges. Surprisingly, ML-3000 had no effect on 5-LOX product synthesis in whole-blood assay. In addition, we could show that inhibition of COX pathways did not increase the transformation of arachidonic acid by the 5-LOX pathway.

Perioperative management of medications for psoriasis and psoriatic arthritis: a review for the dermasurgeon

BACKGROUND

Psoriasis affects an estimated 3% of the world's population. Many are on chronic immunosuppressive therapy for the cutaneous and joint manifestations of this disorder. The management of these medications in the perioperative period is controversial. Psoriasis and psoriatic arthritis medications can affect wound healing, hemostasis, and infection risk during cutaneous surgery.

OBJECTIVES

The objective of this article is to provide a critical review of various medications used for care of the psoriatic patient and their potential effect on cutaneous surgical procedures.

CONCLUSIONS

This review summarizes current understanding of wound healing, hemostatic effects, and infectious risks regarding many psoriasis medications including nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, corticosteroids, various immunosuppressants, and biologic response modifiers. Recommendations vary depending on the agent in question, type of procedure, and comorbid conditions in the patient. Caution is advised when using many of the medications reviewed due to lack of human data of their effects in the perioperative period.

Population pharmacokinetic modelling of the enterohepatic recirculation of diclofenac and rofecoxib in rats

BACKGROUND AND PURPOSE

Enterohepatic recirculation (EHC) is a common pharmacokinetic phenomenon that has been poorly modelled in animals. The presence of EHC leads to the appearance of multiple peaks in the concentration-time profile and increased exposure, which may have implications for drug effect and extrapolation across species. The aim of this investigation was to develop a population pharmacokinetic model for diclofenac and rofecoxib that describes EHC and to assess its consequence for the pharmacodynamics of both drugs.

EXPERIMENTAL APPROACH

The pharmacokinetics of diclofenac and rofecoxib was characterized in male rats following intravenous, intraperitoneal and oral administration. Blood samples were collected at pre-defined time points after dosing to determine plasma concentrations over time. A parametric approach using nonlinear mixed effects modelling was applied to describe EHC, whilst simulations were used to evaluate its impact on PGE(2) inhibition.

KEY RESULTS

For diclofenac, EHC was described by a compartmental model with periodic transfer rate and metabolite formation rate. For rofecoxib, EHC modelling required a conversion compartment with first-order recycling rate and lag time. Based on model predictions, EHC causes an increase of 95% in the systemic exposure to diclofenac and of 15% in the exposure to rofecoxib. In addition, EHC prolongs the inhibition of PGE(2) and increases the duration of the anti-inflammatory effect (24 h for rofecoxib 10 mg kg(-1)) without affecting maximum inhibition.

CONCLUSIONS AND IMPLICATIONS

Our findings show the relevance of exploring EHC in a quantitative manner to accurately interpret pharmacodynamic findings in vivo, in particular when scaling across species.

Roles of ERK and p38 mitogen-activated protein kinases in phorbol ester-induced NF-κB activation and COX-2 expression in human breast epithelial cells

Inappropriate up-regulation of cyclooxygenase-2 (COX-2) has been implicated in pathogenesis of various types of human cancer. Thus, COX-2 has been recognized as an important target for the chemoprevention of several human malignancies including breast cancer. COX-2 expression is known to be regulated by the eukaryotic transcription factor NF-kappaB. In an attempt to link the NF-kappaB activation and COX-2 induction during mammary carcinogenesis, we have examined the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA), a prototype tumor promoter and a mitogen, on NF-kappaB activation and COX-2 expression in the immortalized human breast epithelial cell line (MCF10A). Treatment of MCF10A cells with TPA resulted in transient induction of NF-kappaB DNA binding with maximal activation observed at 30 min. Increased DNA binding of NF-kappaB was accompanied by enhancement of its transcriptional activity as determined by the luciferase reporter gene assay. Under the same experimental conditions, expression of COX-2 mRNA and its protein product peaked at 2h and 4h, respectively. TPA treatment caused an increase in the production of prostaglandin E(2). Treatment of cells with the NF-kappaB inhibitor pyrrolidine dithiocarbamate resulted in significant suppression of TPA-induced COX-2 expression. TPA induced activation of ERK1/2 and p38 mitogen-activated protein kinases (MAPK) via phosphorylation. PD98059 (ERK inhibitor) and SB203580 (p38 MAPK inhibitor) down-regulated the COX-2 expression induced by TPA. Furthermore, TPA-induced COX-2 induction as well as NF-kappaB activation was blocked in MCF10A cells transfected with dominant negative mutant ERK1/2 or p38 MAPK. These results suggest that both p38 and ERK MAPKs activates NF-kappaB signaling, which in turn induces COX-2 expression in TPA-stimulated human mammary epithelial cells.

A tale of switched functions: from cyclooxygenase inhibition to M-channel modulation in new diphenylamine derivatives

Cyclooxygenase (COX) enzymes are molecular targets of nonsteroidal anti-inflammatory drugs (NSAIDs), the most used medication worldwide. However, the COX enzymes are not the sole molecular targets of NSAIDs. Recently, we showed that two NSAIDs, diclofenac and meclofenamate, also act as openers of Kv7.2/3 K(+) channels underlying the neuronal M-current. Here we designed new derivatives of diphenylamine carboxylate to dissociate the M-channel opener property from COX inhibition. The carboxylate moiety was derivatized into amides or esters and linked to various alkyl and ether chains. Powerful M-channel openers were generated, provided that the diphenylamine moiety and a terminal hydroxyl group are preserved. In transfected CHO cells, they activated recombinant Kv7.2/3 K(+) channels, causing a hyperpolarizing shift of current activation as measured by whole-cell patch-clamp recording. In sensory dorsal root ganglion and hippocampal neurons, the openers hyperpolarized the membrane potential and robustly depressed evoked spike discharges. They also decreased hippocampal glutamate and GABA release by reducing the frequency of spontaneous excitatory and inhibitory post-synaptic currents. In vivo, the openers exhibited anti-convulsant activity, as measured in mice by the maximal electroshock seizure model. Conversion of the carboxylate function into amide abolished COX inhibition but preserved M-channel modulation. Remarkably, the very same template let us generating potent M-channel blockers. Our results reveal a new and crucial determinant of NSAID-mediated COX inhibition. They also provide a structural framework for designing novel M-channel modulators, including openers and blockers.

Adjusted indirect comparison of celecoxib versus rofecoxib on cardiovascular risk

To compare the magnitude of celecoxib versus rofecoxib on the cardiovascular risk. We performed adjusted indirect comparison of celecoxib versus rofecoxib for cardiovascular events using two data on The Adenomatous Polyp Prevention on Vioxx (APPROVe) trial and Adenoma Prevention with Celecoxib (APC) trial. Baseline characteristics of the patients and placebos were comparable in both trials, in terms of age, sex, hypertension, diabetes mellitus, smoking, and hypercholesterolemia. The overall incidence of cardiovascular events was similar in both groups (rofecoxib 48/1,287 versus celecoxib 48/1,356, p = 0.79). The relative risks (RRs) of all myocardial infarction or sudden death from cardiac causes were increased in both rofecoxib and celecoxib groups [rofecoxib versus placebo; RR 1.35, 95% confidence interval (CI) 1.07-1.69, p = 0.03, celecoxib versus placebo; RR 1.35, 95% CI 1.14-1.51, p = 0.01]. The RRs for cardiovascular events derived from the adjusted indirect comparisons of the two coxibs did not significantly differ from unity (celecoxib versus rofecoxib; RR 0.95, 95% CI 0.76-1.19, p = 0.67). The adjusted indirect comparison analysis shows that celecoxib and rofecoxib may have similarly effect of cardiovascular events when used for 3 years.

Synergistic depression of NMDA receptor-mediated transmission by ketamine, ketoprofen and L-NAME combinations in neonatal rat spinal cords in vitro

BACKGROUND AND PURPOSE

Spinal N-methyl-D-aspartate (NMDA) receptor/cyclooxygenase (COX) and nitric oxide synthase (NOS) pathways play a major role in nociceptive processing, and influencing them simultaneously may induce synergistic analgesia. This study determined the spinal antinociceptive interactions between ketamine (NMDA receptor channel blocker), ketoprofen (COX inhibitor) and L-NAME (NOS inhibitor) combinations.

EXPERIMENTAL APPROACH

Using an in vitro neonatal rat spinal cord preparation, two A-fibre-mediated reflexes, the monosynaptic reflex (MSR) and the low-intensity excitatory postsynaptic potential (epsp), and one C-fibre-mediated reflex, the high-intensity epsp, were evoked electrically. The effect of drugs and drug combinations on these reflexes was assessed and the type of interaction determined by isobolographic analysis.

KEY RESULTS

Infusion of ketamine alone decreased all three reflexes. That of ketoprofen decreased both the low and the high-intensity epsp only. Infusion of L-NAME alone produced no significant effects. Co-infusion of fixed ratios of IC(40) fractions of both (ketamine+ketoprofen) and (ketamine+L-NAME) were synergistic for depressing the low and the high-intensity epsps. The interaction was sub-additive for both combinations on the MSR. The only significant effect for the (ketoprofen+L-NAME) combination was synergism on the high-intensity epsp.

CONCLUSIONS AND IMPLICATIONS

All three combinations synergistically depressed nociceptive spinal transmission, and both ketamine and ketoprofen and ketamine and L-NAME combinations did so with potentially decreased motor side effects. If such combination profiles also occur in vivo, the present findings raise the possibility of ultimate therapeutic exploitation of increased analgesia with fewer side effects.

Novel 2-(4-methylsulfonylphenyl)pyrimidine derivatives as highly potent and specific COX-2 inhibitors

New series of 2-(4-methylsulfonylphenyl) and 2-(4-sulfamoylphenyl)pyrimidines were synthesized and evaluated for their ability to inhibit cyclooxygenase-2 (COX-2). COX-1 and COX-2 inhibitory activity of these compounds was determined using purified enzyme (PE) and human whole blood (HWB) assays. Extensive structure-activity relationship (SAR) work was carried out within these series, and a wide number of potent and specific COX-2 inhibitors were identified (HWB COX-2 IC(50)=2.4-0.3nM and 80- to 780-fold more selective than rofecoxib).

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Inhibition of cyclooxygenase-2 suppresses lymph node metastasis via reduction of lymphangiogenesis

Cyclooxygenase-2 (COX-2) inhibitor has been reported to suppress tumor progression. However, it is unclear whether this inhibitor can also prevent lymphatic metastasis. To determine the effects of COX-2 inhibitor on lymphatic metastasis, etodolac, a COX-2 inhibitor, was given p.o. to mice bearing orthotopic xenografts or with carcinomatous peritonitis induced with a highly metastatic human diffuse-type gastric carcinoma cell line, OCUM-2MLN. Tumor lymphangiogenesis was significantly decreased in etodolac-treated mice compared with control mice. Consistent with this decrease in lymphangiogenesis, the total weight of metastatic lymph nodes was less in etodolac-treated mice than in control mice. Immunohistochemical analysis revealed that the major source of vascular endothelial growth factor-C (VEGF-C) and VEGF-D was F4/80-positive macrophages in our models. The mRNA levels of VEGF-C in mouse macrophage-like RAW264.7 cells, as well as those in tumor tissues, were suppressed by etodolac. The growth of human dermal lymphatic microvascular endothelial cells was also suppressed by etodolac. Supporting these findings, etodolac also inhibited lymphangiogenesis in a model of chronic aseptic peritonitis, suggesting that COX-2 can enhance lymphangiogenesis in the absence of cancer cells. Our findings suggest that COX-2 inhibitor may be useful for prophylaxis of lymph node metastasis by reducing macrophage-mediated tumor lymphangiogenesis.

Kinetic, thermodynamic and statistical studies on the inhibition of adenosine deaminase by aspirin and diclofenac

The kinetic and thermodynamic effects of aspirin and diclofenac on the activity of adenosine deaminase (ADA) were studied in 50 mM phosphate buffer pH = 7.5 at 27 and 37 degrees C, using UV-Vis spectrophotometry and isothermal titration calorimetry (ITC). Aspirin exhibits competitive inhibition at 27 and 37 degrees C and the inhibition constants are 42.8 and 96.8 microM respectively, using spectrophotometry. Diclofenac shows competitive behavior at 27 degrees C and uncompetitive at 37 degrees C with inhibition constants of 56.4 and 30.0 microM, at respectively. The binding constant and enthalpy of binding, at 27 degrees C are 45 microM, - 64.5 kJ/mol and 61 microM, - 34.5 kJ/mol for aspirin and diclofenac. Thermodynamic data revealed that the binding process for these ADA inhibitors is enthalpy driven. QSAR studies by principal component analysis implemented in SPSS show that the large, polar, planar, and aromatic nucleoside and small, aromatic and polar non-nucleoside molecules have lower inhibition constants.

Atherogenic diet causes lethal ileo-ceco-colitis in cyclooxygenase-2 deficient mice

Cyclooxygenases (COX) regulate a variety of inflammatory diseases, including inflammatory bowel disease (IBD). While the pathological effects of COX-1 inhibition by NSAIDs on intestinal ulceration are well established, the role of COX-2 on intestinal inflammation remains under investigation. In this paper, we report a protective role for COX-2 against diet-mediated intestinal inflammation in mice. COX-2(-/-) mice fed an atherogenic diet or diet containing cholate, but not chow or fat alone, had a high mortality whereas COX-1(-/-) mice and wild-type mice were unaffected by the dietary changes. Histological analysis identified the cause of death in COX-2(-/-) mice due to severe intestinal inflammation that was surprisingly limited to the ileo-ceco-colic junction. COX-2 expression is induced in the cecum of wild-type mice fed an atherogenic diet. Our findings show that COX-2 plays an anti-inflammatory role at the ileo-ceco-colic junction in mice, and the pathology of diet-mediated intestinal inflammation in COX-2(-/-) mice offers an excellent model system to elucidate the molecular mechanisms of intestinal inflammation.

Relative non-steroidal anti-inflammatory drug (NSAID) antiproliferative activity is mediated through p21-induced G1 arrest and E2F inhibition

This study was performed to compare the relative antineoplastic activity of 10 different non-steroidal anti-inflammatory drugs (NSAIDs) in clinical use, and to investigate the underlying mechanisms of this activity in a squamous cell carcinoma of the head and neck model (SCCHN). A standard 5-day MTT assay was used to calculate IC(50) values in UM-SCC-1 cells for 10 NSAIDs, including celecoxib, rofecoxib, sulindac sulfide, sulindac sulfone, indomethacin, ketoprofen, flurbiprofen, naproxen, piroxicam, and aspirin. Celecoxib, a COX-2 specific inhibitor, was by far the most potent NSAID, with an IC(50) of 39.9 +/- 1.1 microM, followed by sulindac sulfide (116.5 +/- 2.34 microM). Celecoxib and sulindac sulfide also induced more activation of caspase-3 than any other NSAID. Cell cycle analysis showed that celecoxib and sulindac sulfide both induced a 3-fold increase in G(1) phase distribution, and this correlated with strong induction of p21(waf1/cip1), inhibition of cyclin D1, and hypophosphorylation of Rb. Celecoxib and sulindac sulfide treatment induced strong downstream inhibition of E2F transactivating activity as determined by a luciferase reporter assay. These data demonstrate the wide range of activity of various NSAID agents, and reveal a mechanism of action through cell cycle inhibition and induction of apoptosis.

Menstrual migraine: clinical and therapeutical aspects

Estrogens fluctuations, particularly their premenstrual fall, are currently regarded as the main triggers of menstrual migraine (MM). MM presents in two clinical forms: pure MM, where attacks are confined to the perimenstrual period (PMP), and menstrually related migraine, where attacks always occur during, but are not confined to, the PMP. MM episodes are usually longer, more intense, more disabling and more refractory than nonmenstrual attacks. Acute management of MM should initially be abortive and primarily sought with triptans. If this fails, short-term perimenstrual prophylaxis with NSAIDs, coxibs, triptans or ergotamine derivatives can be considered. Hormone manipulations, mainly application of percutaneous estradiol gel in PMP or administration of oral contraceptives in extended cycles, constitute an alternative approach for nonresponders.

Condensed bridgehead nitrogen heterocyclic system: synthesis and pharmacological activities of 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole derivatives of ibuprofen and biphenyl-4-yloxy acetic acid

Several 3,6-disubstituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles were prepared by condensation of 4-amino-5-substituted-3-mercapto-(4H)-1,2,4-triazoles (3a,b) with various substituted aromatic acids and aryl/alkyl isothiocyanates through a one-pot reaction. These compounds were investigated for their anti-inflammatory, analgesic, ulcerogenic, lipid peroxidation, antibacterial and antifungal activities. Some of the synthesized compounds showed potent anti-inflammatory activity along with minimal ulcerogenic effect and lipid peroxidation, compared to those of ibuprofen and flurbiprofen. Some of the tested compounds also showed moderate antimicrobial activity against tested bacterial and fungal strains.

Mechanisms underlying the anti-inflammatory activity and gastric safety of acemetacin

BACKGROUND AND PURPOSE

Acemetacin is regarded as a pro-drug of indomethacin and induces significantly less gastric damage but the reasons for this greater gastric safety of acemetacin are unclear. The anti-inflammatory effects of acemetacin have been attributed, at least in part, to its hepatic biotransformation to indomethacin. The aim of this study was to determine the effects of acemetacin and indomethacin in an in vivo model of acute inflammation and to examine the importance of biotransformation of acemetacin (to indomethacin) to its anti-inflammatory actions.

EXPERIMENTAL APPROACH

The zymosan airpouch model was used in rats. Indomethacin or acemetacin (2.7-83.8 micromol kg(-1)) were administered orally or directly into the pouch. Leukocyte infiltration, prostaglandin (PG) E(2) and leukotriene (LT) B(4) levels in exudates, and whole blood thromboxane (TX) B(2) synthesis were measured.

KEY RESULTS

Acemetacin was rapidly converted to indomethacin after its administration. Both acemetacin and indomethacin elicited comparable, dose-dependent reductions of leukocyte infiltration and of PGE(2) and TXB(2) synthesis. However, indomethacin induced more gastric damage than acemetacin and elevated LTB(4) production in the airpouch.

CONCLUSIONS AND IMPLICATIONS

The similar effects of acemetacin and indomethacin on leukocyte infiltration and PG synthesis are consistent with rapid biotransformation of acemetacin to indomethacin. Some of this biotransformation may occur extra-hepatically, for instance in inflammatory exudates. Acemetacin probably exerts actions independent of conversion to indomethacin, given the different effects of these two drugs on LTB(4) production. Such differences may contribute to the relative gastric safety of acemetacin compared to indomethacin.

Surface plasmon resonance studies and biochemical evaluation of a potent peptide inhibitor against cyclooxygenase-2 as an anti-inflammatory agent

Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation [D.L. Dewitt, W.L. Smith, Primary structure of prostaglandin G/H synthase from sheep vesicular gland determined from the complementary DNA sequence, Proc. Natl. Acad. Sci. USA 85 (1988) 1412-1416, 1]. It exists mainly in two isoforms COX-1 and COX-2 [A. Raz, A. Wyche, N. Siegel, P. Needleman, Regulation of fibroblast cyclooxygenase synthesis by interleukin-1, J. Biol. Chem. 263 (1988) 3022-3028, 2]. The conventional non-steroidal anti-inflammatory drugs (NSAIDs) have adverse gastrointestinal side-effects, because they inhibit both isoforms [T.D. Warner, F. Guiliano, I. Vojnovic, A. Bukasa, J.A. Mitchell, J.P. Vane, Nonsteroid drug selectivities for cyclo-oxygenase-1 rather than cyclo-oxygenase-2 are associated with human gastrointestinal toxicity: a full in vitro analysis, Proc. Natl. Acad. Sci. USA 96 (1999) 7563-7568, 3; L.J. Marnett, A.S. Kalgutkar, Cyclooxygenase 2 inhibitors: discovery, selectivity and the future, Trends Pharmacol. Sci. 20 (1999) 465-469, 4; J.R. Vane, NSAIDs, Cox-2 inhibitors, and the gut, Lancet 346 (1995) 1105-1106, 5]. Therefore drugs which selectively inhibit COX-2, known as coxibs were developed. Recent reports on the harmful cardiovascular and renovascular side-effects of the anti-inflammatory drugs have led to the quest for a novel class of COX-2 selective inhibitors. Keeping this in mind, we have used the X-ray crystal structures of the complexes of the COX-1 and COX-2 with the known inhibitors for a rational, structure based approach to design a small peptide, which is potent inhibitor for COX-2. The peptides have been checked experimentally by in-vitro kinetic studies using surface plasmon resonance (SPR) and other biochemical methods. We have identified a tripeptide inhibitor which is a potential lead for a new class of COX-2 inhibitor. The dissociation constant (K(D)) determined for COX-2 with peptide WCS is 1.90x10(-10)M, the kinetic constant (K(i)) determined by spectrophotometry is 4.85x10(-9)M and the IC(50) value is 1.5x10(-8)M by ELISA test.

Modulation of Hypericin Photodynamic Therapy by Pretreatment with 12 Various Inhibitors of Arachidonic Acid Metabolism in Colon Adenocarcinoma HT-29 Cells

One proposal to increase the efficiency of photodynamic therapy (PDT) is to accompany photosensitization with other treatment modalities, including modulation of arachidonic acid (AA) metabolism. The aim of this study was to evaluate the effectiveness of a combined modality approach employing 48 and 24 h pretreatment with various inhibitors of lipoxygenase (LOX; nordihydroguaiaretic acid, esculetin, AA-861, MK-886 and baicalein), cyclooxygenase (COX; diclofenac, flurbiprofen, ibuprofen, indomethacin, SC-560 and rofecoxib) and cytochrome P450-monooxygenase (proadifen) pathways, followed by hypericin-mediated PDT. Cytokinetic parameters like MTT assay, adherent and floating cell numbers, viability and cell cycle distribution analysis were examined 24 h after hypericin activation. Pretreatment of human colon cancer cells HT-29 prior to PDT with 5-LOX inhibitor MK-886 as well as 5, 12-LOX and 12-LOX inhibitors (esculetin and baicalein, respectively) resulted in significant and dose-dependent effects on all parameters tested. Pretreatment with diclofenac, flurbiprofen, ibuprofen and indomethacin, the nonspecific COX inhibitors, promoted hypericin-mediated PDT, but these effects were probably COX-independent. In contrast, application of SC-560 and rofecoxib, specific inhibitors of COX-1 and COX-2, respectively, attenuated PDT. Inhibition of P450 monooxygenase with proadifen implied also the significance of this metabolic pathway in cell survival and cell resistance to hypericin photocytotoxicity. In conclusion, our results testify that application of diverse inhibitors of AA metabolism may have different consequences on cellular response to hypericin-mediated PDT and that some of them could be considered for potentiation of PDT.

Synergistic interaction between meloxicam and aminoguanidine in formalin-induced nociception in mice

OBJECTIVES

The objective of this study was to examine the nature of interaction between cyclooxygenase-2 inhibitor meloxicam and inducible nitric oxide synthase inhibitor aminoguanidine in formalin-induced nociception in mice and the possible therapeutic advantage.

METHODS

Antinociceptive effect of meloxicam (1, 3, 10 and 30 mg/kg, oral) and aminoguanidine (10, 30, 100 and 300 mg/kg, oral) and their combinations was examined in formalin-induced paw licking model in mice. Analysis of variance and isobolographic method were employed to identify the nature of antinociceptive interaction.

RESULTS

Higher doses of meloxicam (10 and 30 mg/kg) and aminoguanidine (100 and 300 mg/kg) produced significant reduction in paw licking time (antinociceptive) in late phase of formalin-induced nociception. Combination of sub-threshold dose of meloxicam (3 mg/kg) with increasing doses of aminoguanidine (10, 30, 100 and 300 mg/kg) resulted in synergistic antinociceptive effect. Similarly, co-administration of sub-threshold dose of aminoguanidine (30 mg/kg) with increasing doses of meloxicam (1, 3, 10 and 30 mg/kg) produced significant reduction in formalin-induced paw licking behaviour. The experimental ED(50) for combination with their confidence limits are below the confidence interval of theoretical line of additive interaction, suggesting synergistic nature of interaction between meloxicam and aminoguanidine in isobolographic analysis.

CONCLUSION

Co-administration of meloxicam and aminoguanidine showed synergistic antinociceptive effect which might possibly reduce gastrointestinal toxicity associated with the use of meloxicam.

Recent developments in nonsteroidal antiinflammatory drugs in cats

Pain, particularly chronic pain, is an underestimated ailment in cats. Veterinarians tend to under-diagnose and under-treat pain in this aloof and stoic species. Until recently, there was only one analgesic (i.e., butorphanol) approved in the United States for use in cats; but many analgesics, particularly opioids, have been used extra-label for this purpose. Nonsteroidal antiinflammatory drugs (NSAIDs) have been used sparingly in cats because of safety concerns, which are less of an issue with the newer agents. Meloxicam is the only NSAID labeled for use in cats in the United States, but other agents are available in this country and are labeled for use in cats in other countries.

Flurbiprofen in the symptomatic management of rheumatoid arthritis: a valuable alternative

BACKGROUND

The withdrawal of certain cyclooxygenase-2 selective drugs and the availability of over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) have increased the pressure for researching and prescribing conventional NSAIDs with a favourable efficacy/tolerance ratio in inflammatory diseases, particularly rheumatoid arthritis. The aim of this comprehensive meta-analysis was to evaluate the absolute and relative efficacy and safety of flurbiprofen in the management of rheumatoid arthritis.

METHODS

A systematic and exhaustive bibliographic research of published literature has been performed. The inclusion criteria are summarised as follows: randomised trial and rheumatoid arthritis and flurbiprofen and oral administration and anti-inflammatory doses from 100 to 300 mg and (placebo or aspirin or indomethacin or naproxen or ibuprofen or ketoprofen) and (articular pain or stiffness or swelling or mobility or patient/physician reported efficacy or tolerance or gastrointestinal (GI) tolerance). Studies were conducted from January 1975 to January 2006. Analyses have been stratified by comparisons and outcomes. Publication bias and robustness have been extensively investigated.

RESULTS

Fourteen studies, accounting for 1103 patient-years, have been included in the quantitative review. The mean daily doses administrated were 200 mg flurbiprofen, 4000 mg aspirin, 150 indomethacin, 750 mg naproxen and 1800 mg ibuprofen. Flurbiprofen was superior to placebo for all outcomes, and superior to three of four other NSAIDs in terms of formal symptomatic measures (pain, stiffness and swelling). Several patients or physicians reported the efficacy of flurbiprofen as superior to indomethacin and naproxen, while its safety, and particularly its GI tolerance were better compared with aspirin and indomethacin. Sensitivity analyses have reported a sufficient robustness against systematic publication bias assumptions.

CONCLUSION

This meta-analysis has shown that flurbiprofen is an interesting alternative to commonly prescribed NSAIDs in the symptomatic management of rheumatoid arthritis, especially given its favourable efficacy/tolerance ratio.

Selective inhibition of prostacyclin synthase activity by rofecoxib

The development of cyclooxygenase-2 (COX-2) selective inhibitors prompted studies aimed at treating chronic inflammatory diseases and cancer by using this new generation of drugs.Yet, several recent reports pointed out that long-term treatment of patients with COX-2 selective inhibitors (especially rofecoxib) caused severe cardiovascular complicances. The aim of this study was to ascertain whether, in addition to inhibiting COX-2, rofecoxib may also affect prostacyclin (PGI2) level by inhibiting PGI2 forming enzyme (prostacyclin synthase, PGIS). In order to evaluate if selective (celecoxib, rofecoxib) and non-selective (aspirin, naproxen) anti-inflammatory compounds could decrease PGI2 production in endothelial cells by inhibiting PGIS, we analyzed the effect of anti-inflammatory compounds on the enzyme activity by ELISA assay after addition of exogenous substrate, on PGIS protein levels by Western blotting and on its subcellular distribution by confocal microscopy. We also analyzed the effect of rofecoxib on PGIS activity in bovine aortic microsomal fractions enriched in PGIS. This study demonstrates an inhibitory effect of rofecoxib on PGIS activity in human umbilical vein endothelial (HUVE) cells and in PGIS-enriched bovine aortic microsomal fractions, which is not observed by using other anti-inflammatory compounds. The inhibitory effect of rofecoxib is associated neither to a decrease of PGIS protein levels nor to an impairment of the enzyme intracellular localization. The results of this study may explain the absence of a clear relationship between COX-2 selectivity and cardiovascular side effects. Moreover, in the light of these results we propose that novel selective COX-2 inhibitors should be tested on PGI2 synthase activity inhibition.

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

Non-prescription (over-the-counter [OTC]) analgesics are used for the short-term treatment of acute painful conditions of mild to moderate intensity in everyday life. Well documented safety and efficacy, a rapid onset of action and a flexible daily dosing regimen are essential in this context. Film-coated, immediate-release, low-dose diclofenac potassium, developed for OTC use, offers a flexible daily dosing regimen with an initial dose of two tablets (2 x 12.5mg) followed by one or two tablets up to a maximum daily dose of six tablets (75 mg/day). The maximum plasma drug concentration is reached 30 minutes after administration, and the mean terminal half-life is 1-2 hours, allowing a 4- to 6-hour duration of activity, depending on the condition. Thirteen randomised, double-blind trials with both placebo and active controls have demonstrated the efficacy of diclofenac potassium 12.5mg tablets in conditions suitable for treatment with OTC medication, for example, acute lower back pain, headache, acute pain after dental extraction, symptoms of cold and influenza (including fever), and dysmenorrhoea. A single dose of diclofenac potassium 12.5mg is the lowest recommended effective dose. A two-tablet single dose of 25mg is at least as effective as ibuprofen 400mg. A flexible dosing regimen of an initial two tablets followed by one or two tablets up to a total daily dose of 75 mg is as effective as ibuprofen used in comparable fashion up to a total daily dose of 1200 mg. The incidence of adverse events in patients taking single or multiple doses of diclofenac potassium is similar to that of ibuprofen and placebo. In a safety study conducted to compare diclofenac potassium with ibuprofen for up to 3 months in patients with osteoarthritis of the knee, no differences in the pattern of adverse events were noted. There was no evidence of either hepatic injury or cardiovascular safety-related issues at any time during the study. Patients are generally capable of taking diclofenac potassium appropriately. A maximum OTC treatment duration of 5 days for pain and 3 days for fever is recommended.

Synthesis and biological activity of new anti-inflammatory compounds containing the 1,4-benzodioxine and/or pyrrole system

A series of substituted derivatives containing the 1,4-benzodioxine or pyrrole nucleus are described. All the newly synthesized compounds were examined for their in vitro and in vivo anti-inflammatory activity. Several derivatives, including (S)-2, 14 and 17, showed more anti-inflammatory activity in vivo in these assays (rat paw oedema induced by carrageenan) than the known classical anti-inflammatory agent ibuprofen, whereas other compounds like 1 were equipotent to ibuprofen. Compound 17 was the most outstanding derivative because of its remarkable in vivo anti-inflammatory activity. In this paper, we examine and discuss the structure-activity relationships and anti-inflammatory activities of these compounds.

Determinants of the short-term gastric damage caused by NSAIDs in man

BACKGROUND

The short-term gastric damage seen with non-steroidal anti-inflammatory drugs (NSAIDs) in man may involve inhibition of cyclooxygenase (COX-1) and COX-2 as well as the topical irritancy, which is dependant on the acidity (pKa) and/or lipophilicity (log P(7.4)).

AIM

To study the quantitative relationship between NSAID-induced short-term gastric damage, their physicochemical properties and contrasting roles of COX-1 and COX-2 inhibition.

METHODS

We identified studies that allowed a qualitative comparison of the gastric injury (Lanza scores) induced by NSAIDs with their pKa and log P(7.4). Damage was correlated with gastric COX inhibition and potency to inhibit COX-1 and 2 and their COX-2/COX-1 selectivity ratio.

RESULTS

The gastric damage correlates significantly with pKa (r = -0.69; P < 0.01), log P (r = -0.58, P < 0.05) and potency of the NSAIDs to inhibit COX-1 (r = -0.61, P < 0.02), but not with COX-2 inhibition or COX-2/COX-1 selectivity.

CONCLUSION

Against a background of COX-1 and COX-2 inhibition, the physicochemical properties of NSAID appear to play an important role in short-term gastric damage.

Selective COX-2 inhibitors, eicosanoid synthesis and clinical outcomes: a case study of system failure

Elucidation of differences between the active sites of COX-1 and COX-2 allowed the targeted design of the selective COX-2 inhibitors known as coxibs. They were marketed as non-steroidal anti-inflammatory drugs (NSAIDs) that had improved upper gastrointestinal (GI) safety compared with older non-selective NSAIDs such as diclofenac and naproxen. Two GI safety studies conducted with arthritis patients demonstrated that in terms of upper GI safety, celecoxib was not superior to diclofenac (CLASS study) but rofecoxib was superior to naproxen (VIGOR study). However, the VIGOR study revealed also that rofecoxib had increased cardiovascular (CV) risk compared with naproxen. This clinical outcome was supported by the existence of plausible eicosanoid-based biological mechanisms whereby selective COX-2 inhibition could increase CV risk. Nevertheless, the existence of CV risk with rofecoxib was successfully discounted by its pharmaceutical company owner, Merck & Co, with the assistance of specialist opinion leaders and rofecoxib achieved widespread clinical use for 4-5 years. Rofecoxib was withdrawn from the market when several clinical trials in colorectal cancer and post-operative pain revealed increased CV risk with not only rofecoxib, but also coxibs. The commercial success of rofecoxib provides a case-study of failure of the medical journal literature to guide drug usage. Attention to ethical issues may have provided a more useful guide for prescribers.