A randomized, double-blind, crossover comparative endoscopy study on the gastroduodenal tolerability of a highly specific cyclooxygenase-2 inhibitor, flosulide, and naproxen

Endoscopic comparison of gastroduodenal injury with over-the-counter doses of new fast-dissolving ibuprofen and paracetamol formulations: a randomized, placebo-controlled, 4-way crossover clinical trial

Background

While gastrointestinal (GI) effects of standard ibuprofen and N-acetyl-p-aminophenol (APAP) have been reported, upper GI injury following treatment with fast-dissolving (FD) formulations of these analgesics has not been investigated. We evaluated upper GI effects of over-the-counter doses of 2 FD ibuprofen products and 1 FD-APAP product.

Methods

In a randomized, placebo-controlled, endoscopist-blinded, 4-way crossover study, 28 healthy subjects received FD ibuprofen 2×200 mg liquid capsules 3 times daily (TID), ibuprofen 2×200 mg tablets TID, FD-APAP 2×500 mg tablets 4 times daily (QID), and placebo 2×500 mg tablets QID for 7 days. The primary end point was gastric mucosal damage assessed by endoscopy using the Lanza scale: 0=normal stomach or proximal duodenum, 1=mucosal hemorrhages only, 2=1 or 2 erosions, 3=numerous (3-10) erosions, and 4=large number of erosions (>10) or ulcer. Secondary end points included duodenal mucosal damage (Lanza scale); gastroduodenal mucosal injury, classified as present (gastric and/or duodenal endoscopy score ≥2) or absent (gastric and/or duodenal endoscopy score <2); and number of hemorrhages, erosions, and ulcers counted separately in the stomach and duodenum.

Results

Significantly greater gastric mucosal injury was observed after treatment with both ibuprofen products vs FD-APAP (p<0.0001 and p=0.0095, respectively). FD-APAP showed no difference from placebo (p=0.4794). The odds of having an incidence of gastroduodenal mucosal injury were over 6 times greater from FD ibuprofen liquid capsule treatment (odds ratio [OR]=6.19, 95% confidence interval [CI]: 1.60, 23.97) and over 3 times greater from ibuprofen tablet treatment (OR=3.19, 95% CI: 0.8, 12.74) vs FD-APAP.

Conclusion

Treatment with 2 ibuprofen products was associated with significant gastric mucosal injury. Of the 4 treatments studied, FD ibuprofen liquid capsules had the highest risk of incidence of gastroduodenal mucosal injury. Treatment with FD-APAP did not induce any clinically or statistically significant gastroduodenal mucosal injury.

Anti-inflammatory effect of resveratrol on adjuvant arthritis rats with abnormal immunological function via the reduction of cyclooxygenase-2 and prostaglandin E2

Rheumatoid arthritis (RA) is a chronic inflammatory disease with unknown etiology. The present study investigated the anti-inflammatory effect of resveratrol on rats with adjuvant arthritis (AA) with abnormal immunological function via the reduction of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2). AA model rats were established by injection of complete Freund's adjuvant and alterations in the rats secondary paw swelling and the polyarthritic scores were observed. Pathological examination of joint tissues was observed by hematoxylin and eosin staining. The proliferation of spleen cells was examined using a 3-(4,5-dimethylthiazol-2‑yl)-2,5-diphenyltetrazolium bromide assay in vitro. The protein expression of COX-2 in the synovial tissues was detected by western blotting. The level of PGE2 in the serum was assayed using an ELISA kit. The results demonstrated that resveratrol (10 or 50 mg/kg) was able to significantly reduce paw swelling and decrease the arthritis scores. Compared with the AA model rats, a significant reduction in the proliferation of concanavalin A-stimulated spleen cells was observed, articular cartilage degeneration with synovial hyperplasia and inflammatory cell infiltration was suppressed and the production of COX-2 and PGE2 in AA rats was reduced by treatment with resveratrol. These results suggest that resveratrol has significant anti-inflammatory effects on AA rats, which may be associated with the reduction of COX-2 and PGE2 inflammatory mediators.

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.

A critical appraisal of COX-2 selective inhibition and analgesia: how good so far?

The development of COX-2 selective inhibitors has opened a new era of clinical investigation in NSAIDs. Discussion of the established concepts of inflammation and therapeutical uses of these drugs has changed the rationale for its clinical use and therapeutic labeling of these drugs. A comprehensive discussion across basic science and clinical areas involved in each of these concepts is presented. This led to a remarkable re-evaluation of our insights on their traditionally proposed mechanisms of analgesia, their side-effects, and the clinical indication of NSAIDs as "over the counter" pain killers. This may shift physicians toward a more rational use of this drug class.

A randomized, double-blind, one-week study comparing effects of a novel COX-2 inhibitor and naproxen on the gastric mucosa

CS-706 is a novel cyclooxygenase-2 (COX-2) inhibitor with potent analgesic, anti-inflammatory, and antitumor properties in animal models. This one-week, multicenter study was undertaken to assess the safety and tolerability of CS-706 and to compare the effects of CS-706 versus naproxen on acute gastrointestinal (GI) mucosal injury. Healthy men and women (n=160) without evidence of underlying gastroduodenal lesions were randomized to placebo, 100 mg CS-706 once daily, 200 mg CS-706 once daily, or 500 mg naproxen twice daily, administered for 7 days. On Day 8, subjects underwent a posttreatment upper GI endoscopy to assess development of gastroduodenal petechiae, erosions, and ulcers. Inhibition of COX-1 and COX-2 activity over the 24-hr postdose interval on Day 7 was determined in 48 subjects (12 per treatment group). CS-706 was safe and well tolerated. The extent of upper GI mucosal injury for both CS-706 dose groups was statistically significantly less than that for naproxen (P < 0.001) and was similar to placebo (P=0.615 and P=0.115 for 100 and 200 mg CS-706, respectively). No subject in placebo or either CS-706 treatment group had gastroduodenal ulcers, compared with 11 (28.2%) subjects treated with naproxen (P < 0.001). Both doses of CS-706 inhibited COX-2 activity to a similar extent as naproxen, whereas neither dose of CS-706 showed meaningful inhibition of platelet COX-1. In contrast, naproxen nearly completely inhibited COX-1 over the dosing interval. We conclude that CS-706, dosed up to 200 mg once daily, has an acute, upper GI toxicity profile similar to that of placebo and significantly superior to that of naproxen.

The cyclooxygenase 2 -765 C promoter allele is a protective factor for Alzheimer's disease

The cyclooxygenase-2 enzyme (COX-2) is of particular importance in the inflammatory response and recent findings have demonstrated a considerable role in Alzheimer's disease (AD) pathogenesis. In order to assess the possible putative role of a COX-2 polymorphism (765G/C) in AD, we examined its distribution in 161 community-based controls and 168 AD clinic-based cases previously recruited from memory disorder clinics in Tampa and Miami, Florida. There were no significant differences between the two groups in age/age of onset or gender. A significant difference was observed in the distribution of the COX-2 -765 alleles between AD cases and controls (chi(2) = 6.565, p = .010; OR = .596; CI = [.401-.888], p = .011), with the frequency of the C allele being higher in controls. In addition, a significant difference was observed for this polymorphism by genotype (chi(2) = 6.561, p = .038) and by presence or absence of C+ genotypes (chi(2) = 6.207, p = .013; OR = .464, CI = [.351-.885], p = .013). In this sample, the C allele of COX-2 -765 promoter polymorphism is associated with decreased risk of Alzheimer's disease, a finding which further supports the involvement of COX-2 in AD etiology.

A randomised, placebo controlled, comparative trial of the gastrointestinal safety and efficacy of AZD3582 versus naproxen in osteoarthritis

OBJECTIVE

To evaluate the gastrointestinal safety and efficacy of the COX inhibiting nitric oxide donator AZD3582 in patients with hip or knee osteoarthritis.

METHODS

970 patients were randomised (7:7:2) to AZD3582 750 mg twice daily, naproxen 500 mg twice daily, or placebo twice daily in a double blind study. The primary end point was the six week incidence of endoscopic gastroduodenal ulcers (diameter > or =3 mm). Overall damage measured on the Lanza scale was a secondary end point. Safety and tolerability assessments included endoscopic upper gastrointestinal erosions and the gastrointestinal symptom rating scale (GSRS). Efficacy was primarily assessed by WOMAC.

RESULTS

The incidence of ulcers with AZD3582 was 9.7% and with naproxen 13.7% (p = 0.07, NS), v 0% on placebo. The incidence of Lanza scores >2 was higher with naproxen (43.7%) than with AZD3582 (32.2%) (p<0.001). Compared with baseline, significantly fewer ulcers and erosions developed in stomach and stomach/duodenum combined, and fewer erosions developed in stomach, duodenum, and both combined on AZD3582 than on naproxen. GSRS reflux and abdominal pain subscale scores were lower for AZD3582 than for naproxen but there was no difference for indigestion, constipation, and diarrhoea. AZD3582 was as effective as naproxen at improving WOMAC scores. Both agents were well tolerated, with no significant effects on blood pressure.

CONCLUSIONS

At doses with similar efficacy in relieving osteoarthritis symptoms, the primary end point of six week endoscopic gastroduodenal ulcer incidence was not significantly different between AZD3582 and naproxen. Most secondary endoscopic gastrointestinal end points favoured AZD3582.

Pharmacokinetics and safety of JTE-522, a novel selective cyclooxygenase-2 inhibitor, in healthy male volunteers

AIMS

The pharmacokinetics and safety profile of JTE-522, 4-(4-cyclohexyl-2 methyloxazol-5-yl)-2-fluorobenzensulphonamide, a novel selective cyclooxygenase-2 inhibitor were investigated in healthy male volunteers.

METHODS

Initially, as a pilot study, five groups of two subjects were given oral doses of 3-100 mg of JTE-522. After safety assessment, subjects were given 150 and 200 mg of JTE-522. The effect of food-intake on the pharmacokinetics of JTE-522 at a dose of 150 mg was examined. In the multiple-dose study, subjects were given 150 mg of JTE-522 once a day for 7 days. Concentrations of unchanged JTE-522 in plasma, blood and urine were determined by high performance liquid chromatography (h.p.l.c.). Concentrations of metabolites were estimated with h.p.l.c. chromatograms and calibration curves for quantification of unchanged JTE-522.

RESULTS

In the course of this study, no serious abnormality attributable to the test drug was observed, suggesting that JTE-522 was well tolerated in healthy subjects. In a single-dose study, the concentrations of JTE-522 in blood were much higher than the corresponding concentrations in plasma. JTE-522 was readily distributed to blood cells and percentage distribution into blood cells was more than 99.0%. However, the values of Cmax in blood at doses of 100, 150, 200 mg JTE-522 were 15241, 20445 +/- 3918 (16333-24556), 20965 +/- 3260 (17544-24386) ng ml-1, respectively. These findings suggest that JTE-522 has a high affinity for blood cells and the distribution into blood cells is limited at the higher doses of over 100 mg. In a multiple dose study, pharmacokinetic parameters including t1/2 and AUC after the fourth administration were comparable with that of the seventh administration. Thus, these findings suggest the absence of accumulation on the multiple-dosing of JTE-522.

CONCLUSIONS

These results indicate that JTE-522 has an acceptable pharmacokinetic profile for clinical use without any serious adverse events as we verified in healthy young male volunteers.

Cyclooxygenase-2 inhibitor for pain management in osteoid osteoma

Thirteen patients with osteoid osteoma were enrolled in a prospective trial to test whether rofecoxib, a selective cyclooxygenase-2 inhibitor, is as effective for pain control as acetylsalicylic acid. Each patient documented the pain level using a visual analog scale, with 0 being no pain and 10 being unbearable pain, during 2 days of no pain medication, 4 days of 500 mg acetylsalicylic acid three times a day, and 10 days of 25 mg rofecoxib once a day. Oral administration of 500 mg acetylsalicylic acid three times a day led to a significant decrease in pain at night, pain at rest, and pain induced by exercise. Twenty-five milligrams rofecoxib given once a day at midday showed the same remarkable improvement in pain at night, pain at rest, and pain induced by exercise. Rofecoxib in comparison with acetylsalicylic acid showed a trend toward lower pain levels in all categories. Rofecoxib offered a significantly better reduction in pain at rest during the day than did acetylsalicylic acid. Results of the current study suggest that pain induction in osteoid osteoma is related to cyclooxygenase-2, an enzyme that is blocked by acetylsalicylic acid and rofecoxib. Conservative medical treatment with rofecoxib for osteoid osteoma is recommended when percutaneous intervention is associated with significant morbidity.

Acute and chronic pain management in palliative care

Every palliative care patient should have the expectation that acute and chronic pain management will be an integral part of their overall care. However, in all too many instances, the pain of cancer is often grossly under-treated. This issue is of concern because more than 80% of patients with cancer pain can find adequate relief through the use of simple pharmacological methods. It is even more troubling to note that women and minority groups have their cancer pain under-treated more frequently. Physicians with the basic skills of assessment and treatment will be able to control the symptoms in the majority of cancer pain patients. However, there are still some patients who may require other modalities to control their moderate to severe pain. A thorough understanding of all pain management options will help the gynaecological oncologist to maintain an acceptable quality of life for their patients throughout the therapeutic and palliative phases of care.

Where is the evidence that cyclooxygenase inhibition is the primary cause of nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal injury? Topical injury revisited

In this commentary, we take a critical look at the concept that the gastrointestinal (GI) side-effects of nonsteroidal anti-inflammatory drugs (NSAIDs) are due to the ability of these drugs to inhibit cyclooxygenase-1 (COX-1) that is constitutively expressed in the GI mucosa. Indeed, development of the new "super aspirins," such as Celebrex and Vioxx, that selectively inhibit the inducible COX-2, expressed in areas of inflammation, is a direct outgrowth of this concept. We discuss evidence from both the laboratory and the clinic that appears to be inconsistent with the above concept, and cite a number of examples where the depletion of mucosal prostaglandin levels and the development of GI injury can be dissociated. Instead, we revisit the possibility that NSAID-induced GI side-effects are mostly due to the ability of these drugs to topically injure the GI mucosa. We devote the remainder of the commentary to presenting evidence from our and other laboratories that NSAIDs can directly attenuate the surface hydrophobic barrier of the GI mucosa due to their ability to bind to zwitterionic phospholipids, and that even systemically administered NSAIDs that are secreted into the bile may induce GI ulceration and/or bleeding due to phospholipid interactions and the development of topical mucosal injury.

The role of cyclooxygenase and lipoxygenase in cancer chemoprevention

The involvement of prostaglandins (PGs) and other eicosanoids in the development of human cancer has been known for over two decades. Importantly, an increase in PG synthesis may influence tumor growth in human beings and experimental animals, and numerous studies have illustrated the effect of PG synthesis on carcinogen metabolism, tumor cell proliferation and metastatic potential. PGs produced by cyclooxygenases (COXs) are represented by a large series of compounds that mainly enhance cancer development and progression, acting as carcinogens or tumor promoters, with profound effects on carcinogenesis. Further investigations suggest that arachidonic acid (AA) metabolites derived from lipoxygenase (LOX) pathways play an important role in growth-related signal transduction, implying that intervention through these pathways should be useful for arresting cancer progression. We discuss here the implications of COX and LOX in colon, pancreatic, breast, prostate, lung, skin, urinary bladder and liver cancers. Select inhibitors of COX and LOX are described, including nonsteroidal antiinflammatory drugs (NSAIDs), selective COX-2 inhibitors, curcumin, tea, silymarin and resveratrol, as well as a method useful for evaluating inhibitors of COX. Although a substantial amount of additional work is required to yield a better understanding of the role of COX and LOX in cancer chemoprevention, it is clear that beneficial therapeutic effects can be realized through drug-mediated modulation of these metabolic pathways.

Bowen's disease (squamous cell carcinoma in situ) in immunosuppressed patients treated with imiquimod 5% cream and a cox inhibitor, sulindac: potential applications for this combination of immunotherapy

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) often have a protracted course. However, all these patients are immunosuppressed and may have a high incidence of cutaneous malignancies.

OBJECTIVE

To determine if combination therapy using topical imiquimod cream 5% and the oral cyclooxygenase (COX) inhibitor are useful in the therapy of squamous cell carcinoma in situ (SCC in situ)/Bowen's disease in patients with long-standing CLL.

METHODS

Five CLL patients with head and neck cutaneous SCC in situ, which met criteria for Bowen's disease, were treated with topical 5% topical imiquimod cream and an oral COX inhibitor, sulindac 200 mg twice a day.

RESULTS

All patients showed clinical resolution and histologic clearing of the tumors after 16 weeks of therapy.

CONCLUSION

The local immune modulator, 5% imiquimod, in combination with a COX inhibitor, with its many potential antitumor effects may stimulate the innate and possibly the adaptive immune responses to clear these malignancies.

[Gastrointestinal sparing anti-inflammatory drugs--COX-2 selective inhibitors and NO-releasing NSAIDs]

The use of NSAIDs is associated with a wide array of alterations in the gastrointestinal integrity and function. Various approaches have been taken to develop NSAIDs with reduced gastrointestinal toxicity, and few have successfully reduced the incidence of adverse reactions. These include COX-2 selective inhibitors and NO-releasing NSAIDs. Much has been written about the potential of COX-2 inhibitors as antiinflammatory agents that lack the gastrointestinal side effects of traditional NSAIDs. COX-2 expression is most evident at sites of inflammation, while COX-1 accounts for most of the PG synthesis in the normal gastrointestinal tract. However, there are distinct examples of circumstances in which COX-2-derived PGs play a role in the maintenance of the mucosal integrity, and the differentiation of COX-1 and COX-2 is not quite as clear as has been suggested. On the other hand, the rational behind the NO-releasing NSAIDs is that NO released from the derivatives exerts beneficial effects on the gastrointestinal mucosa. The present article overviews the roles of COX and NO in housekeeping functions of the gastrointestinal mucosa in various circumstances and the effects of gastrointestinal sparing NSAIDs, such as COX-2 selective inhibitors and NO-releasing NSAIDs, on the ulcerogenic and healing responses in the gastrointestinal mucosa.

Cox-2-specific inhibitors: definition of a new therapeutic concept

Nonsteroidal anti-inflammatory drugs have been a mainstay in the treatment of inflammatory diseases such as rheumatoid arthritis. However, these agents can result in severe and occasionally life-threatening adverse effects that can limit therapeutic benefit. Progress toward safer anti-inflammatory therapy was aided by the discovery that cyclooxygenase (COX) exists as two isozymes, COX-1 and COX-2. Both isozymes form prostaglandins that support physiologic functions; however, the formation of proinflammatory prostaglandins is catalyzed by COX-2. Inhibition of COX-2 accounts for the anti-inflammatory and analgesic action of NSAIDs; however, concurrent inhibition of COX-1 inhibits prostaglandin-dependent mechanisms such as gastroduodenal mucosal defense and platelet aggregation. This inhibition is the basis of the gastrointestinal toxicity and bleeding characteristic of these drugs. These findings led to the hypothesis that agents that selectively inhibit COX-2 would possess anti-inflammatory and analgesic action but would spare COX-1, thereby avoiding adverse effects in the gastrointestinal tract and platelets. Selective COX-2 inhibitors are now available. The novelty of these agents has raised questions in the medical community as to what constitutes selectivity for COX-2. This review outlines the criteria that must be met to characterize a compound as COX-2-specific. Clinical evidence of clear improvement in gastrointestinal tolerability and safety must be demonstrated in addition to complementary evidence of COX-2 selectivity obtained from enzyme, biochemical, and clinical pharmacology evaluations.

Management of Inflammatory Pain with Selective COX-2 Inhibitors: Promises and Facts

The discovery that two cyclooxygenase (COX) isoenzymes, including inducible forms (COX-2), could be selectively inhibited has triggered new research to develop selective inhibitors. During this process, pharmacotherapeutic concepts in inflammatory pain, and clinicians over-expectations, have created some degree of uncertainty for clinicians about the promise of COX-2 inhibitors and the real role they play. The purpose of this article is to critically review, within the context of NSAIDs, some of the old and new concepts in the management of inflammatory pain, as well as to examine the current evidence of the usefulness of COX-2 inhibitors today.

COX-2 and colon cancer: potential targets for chemoprevention

Evidence derived from several lines of investigation suggest that prostaglandins, metabolites of arachidonic acid, play an important role in colon cancer development. Elevated prostaglandin levels are found in colon cancers and their precursor lesions, adenomatous polyps. Agents such as aspirin and NSAIDs, which inhibit the generation of these arachidonic acid metabolites, are associated with a decreased risk of developing or dying from colon cancer. Both the amount of the agent used and the duration of exposure seem to be important variables. In animals, NSAIDs are among the most potent agents discovered for the reduction of tumors in both genetic and carcinogen-induced models. Data from human trials also suggests that NSAIDs such as sulindac can reduce the size and number of polyps in individuals with familial adenomatous polyposis (FAP). In parallel with the above findings, it is now understood that at least two forms of the enzyme responsible for the metabolism of arachidonic acid exist. One of these forms, COX-1, is generally considered a constitutive form that is responsible for maintaining normal physiologic function. Inhibition of COX-1 leads to many of the clinically undesirable side effects associated with NSAID use. The other known form of the enzyme, COX-2, is an inducible form that is found in increased levels in inflammatory states and in many cancers and their associated pre-malignant lesions. Levels of COX-2 are increased by exposure to mitogens and growth factors. Agents that specifically inhibit COX-2 are now in clinical development and appear to be well-tolerated and effective for the treatment of osteoarthritis and rheumatoid arthritis. The potential for use of COX-2 specific NSAIDs in the prevention of colon cancer is suggested from the distribution of COX-2 in adenomatous polyps and colon cancer and the effectiveness of these agents in genetic and carcinogen-induced animal models of colon cancer. The development of these agents for the prevention of colon cancer will be discussed.

Cellular distribution of prostanoid EP receptors mRNA in the rat gastrointestinal tract

The inhibition of PGE(2) synthesis resulting from sustained NSAIDs therapy has been linked to gastrointestinal irritations and ulceration. The multiple physiological effects of PGE(2) in the gut are mediated through the activation of four receptors termed EP(1-4). The aim of the study was to determine the precise distribution of the four prostaglandin E(2) receptors in the rat stomach, small intestine, and colon. We used non-radioactive in situ hybridization techniques on paraffin-embedded tissue. Mucous cells of the stomach and goblet cells of the small intestine and colon were found to express mRNA for all four EP subtypes. A positive hybridization signal for EP(1), EP(3), and EP(4) was detected in the parietal cells of the stomach whereas the chief cells expressed low levels of EP(1) and EP(3). The EP(1) and EP(3) receptor mRNA could also be detected in the muscularis mucosa, longitudinal muscle and enteric ganglias of the stomach and small intestine. However, close examination of the enteric ganglias indicated that most of the positive labeling was localized to the glial cells, although some neurons did express EP(3). In conclusion, we have detailed the distribution of prostanoid EP receptors in the gut at the cellular level, giving new insights to the role of prostaglandins in gastrointestinal functions.

Nonsteroidal anti-inflammatory drug gastrointestinal toxicity

Nonsteroidal anti-inflammatory drugs (NSAIDs) are currently the most widely used class of therapeutic agents. By inhibiting cyclooxygenase (COX) and reducing gastrointestinal prostaglandins, they provide effective analgesia and suppress inflammation in a variety of conditions. However, through the same mechanism of COX inhibition, they also cause significant gastrointestinal toxicity. One of the most common methods to reduce NSAID-induced gastrointestinal toxicity has been to co-prescribe prophylactic therapies such as acid-reducing agents or the synthetic prostaglandin analogue, misoprostol. More recently safer NSAIDs, such as the COX-2 specific NSAIDs or the nitric oxide-releasing NSAIDs, have been developed or are currently in development. This article reviews mechanisms of NSAID-induced gastrointestinal toxicity. Also reviewed are data on the gastrointestinal consequences of the prophylatic co-therapies, COX-2 specific NSAIDs and nitric oxide-releasing NSAIDs.

Nonoperative treatment of low back pain

Low back pain is a common problem with substantial social and economic issues. Physicians continue to have difficulty managing this condition despite an increased awareness of its magnitude. In addition, there is a misperception about the outcome of patients affected with low back pain; most continue to suffer from pain. We present a nonoperative approach and review various diagnostic and treatment strategies with respect to both scientific and clinical merit. Although many treatment strategies have not been well proved in the scientific literature, thoughtful review of the available information provides a basis for the use of these treatment methods in the patient with refractory pain. This approach can be used in conjunction with existing information to assist clinicians in the management of patients with acute low back pain.

Pharmacologic therapy of osteoarthritis

This article presents a brief review of the most current therapies that are used for the relief of the symptoms related to osteoarthritis. The agents used either systematically or locally are described, providing the rationale for their usage in the treatment of osteoarthritis. Moreover, new therapies that have reached clinical evaluations and that can possibly reduce or stop the progression of the disease--namely the inhibitors of metalloproteases--are presented. Overall, it is obvious that significant progress has been made toward the development of new therapeutic agents to reduce the symptoms as well as the structural changes of the disease.

Non-steroidal anti-inflammatory drugs (NSAIDs) and gastro-intestinal toxicity: current issues

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used drugs and their widespread use is associated with increased gastro-intestinal toxic effects such as ulceration, haemorrhage, perforation and death. They result in these complications mainly by reducing cytoprotective prostaglandins (PGE2 and PGI2) in the stomach, through the inhibition of cyclo-oxygenase (COX) enzyme. The increased morbidity and mortality, in addition to enormous cost, associated with NSAID-associated side effects, necessitates a need for safer GI-friendly NSAID. Various approaches have been used to counteract NSAID associated side effects with varying degrees of success and acceptance. These include the use of alternative analgesia, anti-acid secretory agents like proton pump inhibitors, sucralfate and prostaglandin analogues. In addition, new types of NSAIDs are being developed, based on new understanding of their mechanism of action and the pathogenesis of inflammation. These include a new class of NSAIDs called "selective Cox-2 inhibitors". These agents preserve the COX-1 that is responsible for the production of cytoprotective prostaglandins in the stomach and selectively inhibit COX-2 induced at the sites of inflammation. Selective COX-2 inhibitors exert the same analgesic and anti-inflammatory effects as the existing NSAIDs but may be less toxic to the stomach. In this review the background development and well-structured clinical trials on this new generation NSAIDs are discussed.

Review article: nonsteroidal anti-inflammatory drug-associated gastrointestinal complications--guidelines for prevention and treatment

Chronic ingestion of NSAIDs increases the risk for gastrointestinal complications, which range from dyspepsia to gastrointestinal bleeding, obstruction, and perforation. Among patients using NSAIDs, 0.1 to 2.0% per year suffer serious gastrointestinal complications. Patients who require analgesic therapy should be carefully assessed for the lowest possible dosage and shortest duration of NSAID use and for the potential of treatment with a non-NSAID pain reliever. These patients should also be assessed for factors that increase their risk of gastrointestinal complications, including increased age, concomitant anticoagulant or corticosteroid use, and past history of NSAID-associated gastrointestinal complications. The exact association between Helicobacter pylori infection and NSAID-related ulcer disease is unclear, and the routine testing and treatment of all NSAID using patients for H. pylori infection is not recommended at this time. NSAID-using patients who suffer from dyspepsia should have NSAIDs discontinued, the dosage changed, or be changed to a different class of NSAID. If NSAIDs cannot be discontinued, then an antisecretory agent should be initiated. Misoprostol prevents NSAID-associated gastrointestinal complications. Proton pump inhibitors are the most effective at healing NSAID-associated ulcers among patients who cannot discontinue NSAID therapy.

Distribution and regulation of cyclooxygenase-2 in carrageenan-induced inflammation

1 We characterized the regulation of cyclooxygenase-2 (COX-2) at the mRNA, protein and mediator level in two rat models of acute inflammation, carrageenan-induced paw oedema and mechanical hyperalgesia. 2 Carrageenan was injected in the hind paw of rat at low (paw oedema) and high doses (hyperalgesia). COX-2 and prostaglandin E2 (PGE2) levels were measured by RT-PCR and immunological assays. We also determined the distribution of COX-2 by immunohistochemistry. 3 The injection of carrageenan produced a significant and parallel induction of both COX-2 and PGE2. This induction was significantly higher in hyperalgesia than in paw oedema. This was probably due to the 9 fold higher concentration of carrageenan used to provoke hyperalgesia. 4 Immunohistochemical examination showed COX-2 immunoreactivity in the epidermis, skeletal muscle and inflammatory cells of rats experiencing hyperalgesia. In paw oedema however, only the epidermis showed positive COX-2 immunoreactivity. 5 Pretreatment with indomethacin completely abolished the induction of COX-2 in paw oedema but not in hyperalgesia. 6 These results suggest that multiple mechanisms regulate COX-2 induction especially in the more severe model. In carrageenan-induced paw oedema, prostanoid production have been linked through the expression of the COX-2 gene which suggest the presence of a positive feedback loop mechanism.

Immunolocalization of cyclooxygenase-2 in the macula densa of human elderly

To gain insight into the role of prostanoids in human kidney function, we examined the distribution of cyclooxygenase (COX) 1 and COX-2 by immunofluorescence and immunohistochemistry in human kidneys from adults of various age groups. COX-1 was detected in the collecting ducts, thin loops of Henle and portions of the renal vasculature. COX-2 was detected in the renal vasculature, medullary interstitial cells, and the macula densa. In addition, COX-2 immunoreactivity was noted in afferent arteries and the macula densa of the renal cortex and was more evident in the kidneys of older adults.

Phospholipid association reduces the gastric mucosal toxicity of aspirin in human subjects

OBJECTIVE

In previous studies on rats, we have shown that aspirin (ASA)-induced injury to the gastric mucosa is markedly reduced or completely abolished if ASA is chemically associated with the phospholipid, phosphatidylcholine (PC). We have also shown that the protective effect of PC does not influence the ability of ASA to inhibit mucosal cyclooxygenase (COX) activity in the stomach and other tissues. We therefore sought to assess the effect of PC-associated ASA (ASA/PC) on the gastric mucosa of normal volunteers and to compare the results with the use of ASA alone.

METHODS

Sixteen normal healthy subjects were administered ASA or ASA/PC in a randomized, double-blind, crossover study. The subjects received ASA in a dose of 650 mg three times a day for 3 days or an equivalent dose of ASA chemically associated with PC. Endoscopy was performed at baseline and again on the morning of day 4, after the subjects had taken the final dose of the test drug. On both occasions, antral biopsy specimens were obtained for the assessment of mucosal COX activity and prostaglandin concentration.

RESULTS

The number (mean +/- SD) of gastric erosions seen with the ASA/PC formulation was significantly less than when ASA was used alone (8.7 +/- 10.7 vs 2.9 +/- 4.3; p < 0.025). A similar trend was seen in the duodenum but the difference was statistically not significant. The antral mucosal COX activity, as well as the level of prostaglandin 6-keto PGF1alpha, were reduced significantly (80-88%) and to a similar extent by both ASA and ASA/PC.

CONCLUSIONS

The present study shows that acute aspirin-induced damage to the gastric mucosa can be reduced by chemically associating ASA with PC. The mechanism of mucosal protection provided by this compound is not related to any alteration in the ability of ASA to inhibit mucosal COX activity. We believe this protection is attributable to the maintenance of the defensive hydrophobic barrier of the gastric mucosa.

Clinical pharmacokinetics of nabumetone. The dawn of selective cyclo-oxygenase-2 inhibition?

Nabumetone is a nonsteroidal anti-inflammatory drug (NSAID) of the 2,6-disubstituted naphthyl-alkanone class. Nabumetone is metabolised to an active metabolite 6-methoxy-2-napthylacetic acid (6-MNA) which is a relatively selective cyclo-oxygenase-2 inhibitor that has anti-inflammatory and analgesic properties. Nabumetone and its metabolites bind extensively to plasma albumin. Nabumetone is eliminated following biotransformation to 6-MNA, which does not undergo enterohepatic circulation and the respective glucoroconjugated metabolites are excreted in urine. Substantial concentrations of 6-MNA are attained in synovial fluid, which is he proposed site of action in chronic inflammatory arthropathies. A smaller area under the plasma concentration-time curve (AUC) is evident at steady state as compared with a single dose; this is possibly due to an increase in the volume of distribution and saturation of protein binding. Relationships between 6-MNA concentrations and the therapeutic and toxicological effects have yet to be elucidated for this NSAID. Renal failure significantly reduces 6-MNA elimination but steady-state concentrations of 6-MNA are not increased, possibly because of nonlinear protein binding. Elderly patients with osteoarthritis demonstrate decreased elimination and increased plasma concentrations of nabumetone as compared with young healthy volunteers. Rheumatic disease activity also influences 6-MNA plasma concentrations, as patients with more active disease and lower serum albumin concentrations demonstrate a lower area under the plasma concentration versus time curve. A reduced bioavailability of 6-MNA in patients with severe hepatic impairment is also evident. Dosage adjustment may be required in the elderly, patients with active rheumatic disease and those with hepatic impairment, but not in patients with mild-to-moderate renal failure.