Nephrotoxic potential of selective cyclooxygenase-2 inhibitors

OBJECTIVE: To determine the relative nephrotoxic potential of cyclooxygenase (COX)-2 inhibitors. DATA SOURCES: A MEDLINE search (1996-February 2004) identified clinical trials evaluating the nephrotoxicity of COX-2 inhibitors versus traditional nonsteroidal antiinflammatory drugs (NSAIDs). Key search terms included cyclooxygenase inhibitors, nonsteroidal antiinflammatory agents, nephrotoxicity, and chemically induced. DATA SYNTHESIS: Three clinical trials determined that COX-2 inhibitors have similar adverse effects on the kidney when compared with nonselective NSAIDs, while 2 studies concluded that COX-2 inhibitors are less nephrotoxic than nonselective NSAIDs. All 5 trials utilized low numbers of subjects, short-term therapy, and surrogate markers of kidney damage. CONCLUSIONS: COX-2 inhibitors may not offer distinct advantages over nonselective NSAIDs with respect to kidney function. Longer trials in patients with comorbidities are warranted. These agents should be used cautiously or not at all in patients with predisposing conditions.     

Reducing clinically significant gastrointestinal toxicity associated with nonsteroidal antiinflammatory drugs

OBJECTIVE: To evaluate the efficacy of treatment strategies to reduce clinically significant gastrointestinal adverse effects associated with nonsteroidal antiinflammatory drugs (NSAIDs). DATA SOURCES: A MEDLINE search (1966-November 2003) was performed to identify relevant articles. Key search terms included proton-pump inhibitors, histamine H2 antagonists, misoprostol, cyclooxygenase-2 (COX-2) selective inhibitors, nonsteroidal antiinflammatory agents, stomach ulcer, prevention, and economics. Additional references were obtained from cross-referencing the bibliographies of selected articles. STUDY SELECTION AND DATA EXTRACTION: All information obtained from the MEDLINE search was reviewed. To provide the most clinically relevant information, only randomized controlled trials are included in this review. DATA SYNTHESIS: Clinically significant upper gastrointestinal adverse events, such as ulcers and ulcer complications, associated with NSAIDs are a cause of significant morbidity and mortality in the US. Interest in strategies to reduce the risk of these adverse events is high among clinicians and patients. Misoprostol, high-dose H2-receptor antagonists, proton-pump inhibitors, and COX-2 inhibitors have been shown to reduce this risk. Misoprostol and proton-pump inhibitors are more effective than H2-receptor antagonists; dose-related diarrhea limits the clinical utility of misoprostol. These strategies may not provide enough protection in patients taking concomitant low-dose aspirin therapy or patients with a history of ulcer complications. CONCLUSIONS: COX-2 inhibitors and proton-pump inhibitors are effective and well-tolerated therapies to reduce clinically significant upper gastrointestinal adverse events associated with NSAIDs.     

Etoricoxib: a highly selective COX-2 inhibitor

OBJECTIVE: To review the available literature evaluating the pharmacology, pharmacokinetics, clinical efficacy, and adverse effects of etoricoxib, a highly selective cyclooxygenase-2 (COX-2) inhibitor that is not currently approved for use in the US. DATA SOURCES: Literature retrieval was accessed through MEDLINE (1966-December 2004), Current Contents (1998-December 2004), and Cochrane Library (4th quarter 2004). References from retrieved articles, information from the manufacturer, and abstracts from the American College of Rheumatology and Annual European Congress of Rheumatology meetings were searched. STUDY SELECTION AND DATA EXTRACTION: All clinical trials published in English evaluating etoricoxib were included in this review. An abstract was excluded if it presented preliminary data from trials that are now published, analyzed data previously reported in a published clinical trial, or compared etoricoxib with placebo for an indication with published active-comparator controlled trials. DATA SYNTHESIS: Twelve clinical trials evaluating efficacy were reviewed. Efficacy for acute pain has been evaluated in acute gout, primary dysmenorrhea, and dental surgery and for chronic pain in rheumatoid arthritis, osteoarthritis, and chronic lower back pain. For safety, 3 clinical trials and 6 retrospective analyses of gastrointestinal, renovascular, or cardiovascular adverse effects were reviewed. CONCLUSIONS: Available studies demonstrate the efficacy of etoricoxib compared with nonsteroidal antiinflammatory drugs, but no published studies to date have compared etoricoxib with other selective COX-2 inhibitors. While these agents have demonstrated a significant reduction in gastrointestinal adverse effects, the cardiovascular adverse effects of selective COX-2 inhibition are not well defined. Further study is necessary to delineate the benefits and risks of etoricoxib compared with alternative treatment regimens.     

Use of NSAIDs for the chemoprevention of colorectal cancer

OBJECTIVE: To discuss the role of nonsteroidal antiinflammatory drugs (NSAIDs) in the chemoprevention of colorectal cancer. DATA SOURCES: A MEDLINE search (1966-May 2003) was performed to identify key literature. Search items included, but were not limited to, NSAIDs, colorectal cancer, chemoprevention, cyclooxygenase-2 (COX-2)-specific inhibitors, and familial adenomatous polyposis (FAP). STUDY SELECTION AND DATA EXTRACTION: The search included experimental (in vitro and animal models) and clinical studies evaluating the use of NSAIDs for the chemoprevention of colorectal cancer. The MEDLINE search was supplemented by references from selected articles. DATA SYNTHESIS: Numerous experimental, epidemiologic, and clinical studies suggest that NSAIDs have promise as anticancer agents. The mechanism by which NSAIDs lead to decreased colon carcinogenesis is not fully understood, but may involve restoration of apoptosis and inhibition of prostaglandin-mediated angiogenesis. Compelling evidence from many observational studies has consistently documented a 40-50% reduction in the risk of adenomatous polyps, colorectal cancer incidence, and mortality in patients using NSAIDs. Recent randomized, controlled trials have demonstrated a benefit with aspirin in reducing the rate of development of new or recurrent adenomas in high-risk patients. In addition, randomized studies using sulindac and celecoxib in patients with FAP have documented significant regression of existing adenomatous polyps. CONCLUSIONS: Inhibition of COX-2 is an example of a targeted approach to the chemoprevention of colorectal cancer. However, controversy exists about the safety, efficacy, and optimal treatment regimen of NSAIDs as long-term chemopreventive agents in the general population. Ongoing studies in high-risk patients with both selective and nonselective COX inhibitors will provide important information in the area of colorectal chemoprevention, but clinical trials' use of adenomas as surrogate markers for chemoprevention trials makes their application to the general population limited.     

Development and clinical application of COX-2-selective inhibitors for the treatment of osteoarthritis and rheumatoid arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are among the most prevalent chronic illnesses and leading causes of disability in the United States. The clinical symptoms of OA and RA, pain and inflammation, are biologic processes mediated in part by prostanoids-prostaglandins, prostacyclin, and thromboxanes. The intermediate enzymes responsible for prostaglandin biosynthesis, cyclooxygenase (COX)-1 and COX-2, have been the target of arthritis therapy using nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). An understanding of the biochemistry and molecular pharmacology of COX enzymes has allowed for the development of agents that specifically inhibit COX-2. COX-2-selective inhibitors have efficacy in OA and RA that is similar to that of NSAIDs but with a lower potential for upper gastrointestinal injury, a serious side effect of nonselective NSAIDs. COX-2-selective inhibitors have been increasingly used in the treatment of OA and RA as well as other inflammatory arthropathies including ankylosing spondylitis and gout. Clinical trials with two currently available drugs, rofecoxib and celecoxib, have demonstrated efficacy comparable to nonselective NSAIDs but with a lower risk of gastrointestinal side effects. In general, these drugs are well tolerated in patients with aspirin-sensitive asthma. Rofecoxib is well tolerated in patients with sulfonamide sensitivities; further studies are needed to fully characterize the utility of celecoxib in these patients. Clinical experience shows that because of their improved GI safety, rofecoxib and celecoxib, and newer COX-2-selective inhibitors (valdecoxib, etoricoxib, parecoxib), represent a significant advance in the treatment of arthritis and other related inflammatory conditions.     

The role of rofecoxib, a cyclooxygenase-2-specific inhibitor, for the treatment of non-cancer pain: a review.

Rofecoxib was the first specific inhibitor of cyclooxygenase-2 (COX-2) approved for the treatment of acute pain. It has been shown to provide analgesia that is significantly better than placebo and has an onset of action and efficacy similar to that of traditional nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), such as naproxen and ibuprofen. In addition, the analgesic efficacy of rofecoxib has been demonstrated to be superior to that of the opioid combination of codeine 60 mg/acetaminophen 600 mg in an acute dental pain model. For the treatment of acute pain, the efficacy of rofecoxib was further demonstrated in a study of patients who had undergone orthopedic surgery. Rofecoxib has been found to be as effective as naproxen sodium and more effective than placebo in studies evaluating its use for the treatment of primary dysmenorrhea. In patients with osteoarthritis (OA) of the knee or hip, rofecoxib is superior to placebo and similar to diclofenac and ibuprofen in relieving OA pain and improving physical function. Rofecoxib has also been shown to be superior to acetaminophen and celecoxib after 6 weeks of treatment for OA. The efficacy of rofecoxib has also been demonstrated in patients with rheumatoid arthritis and low back pain. The advantages of using COX-2-specific NSAIDs include convenient once-daily dosing schedule and improved safety compared with traditional NSAIDs. Two large outcomes studies, VIGOR and CLASS, have shown that gastric mucosal ulceration occurs significantly less often in patients taking COX-2-specific inhibitors than in those treated with ibuprofen, diclofenac, or naproxen and occurs with a similar incidence to that of placebo. Absence of any effect on platelet aggregation and bleeding time further distinguishes these agents from traditional NSAIDs. Because COX-2-specific inhibitors do not have an antiplatelet effect, they cannot be used as a substitute for low-dose aspirin for cardiovascular prophylaxis. Rofecoxib is a safe and highly effective alternative to previously available NSAIDs and should be considered for the treatment of acute pain conditions in adult patients, especially those at risk for developing gastrointestinal complications. It is preferred in the perioperative setting because of its analgesic efficacy and lack of platelet effects. Because of its more favorable gastrointestinal toxicity profile compared with nonselective NSAIDs, rofecoxib is safer in patients, especially older patients, for whom chronic anti-inflammatory or analgesic therapy is indicated.     

Selective cyclooxygenase-2 inhibitors for the treatment of arthritis.

The purpose of this paper is to review the rationale for a new class of nonsteroidal anti-inflammatory drugs (NSAIDs) known as selective cyclooxygenase (COX)-2 inhibitors and to present preliminary clinical data on 2 COX-2 inhibitors that are approved for use in the United States. The primary mechanism of NSAIDs in the treatment of inflammation is the inhibition of COX, which exists in 2 forms. COX-I appears to regulate many normal physiologic functions, and COX-2 mediates the inflammatory response. Theoretically, an NSAID that inhibits COX-2 selectively should decrease inflammation but not influence normal physiologic functions and thus should cause fewer gastrointestinal side effects. Preliminary data suggest that celecoxib, a highly selective COX-2 inhibitor, is superior to placebo and similar to traditional NSAIDs in the short-term treatment of pain due to osteoarthritis, although it has been associated with adverse effects such as headache, change in bowel habits, abdominal discomfort, and dizziness. Celecoxib also has been shown to be as effective as traditional NSAIDs in the treatment of rheumatoid arthritis, but it may cause fewer adverse effects, including endoscopically documented ulcers. Celecoxib is metabolized in the liver by the cytochrome P-450 isozyme CYP2C9, and thus serious drug interactions are possible. In the treatment of osteoarthritis, rofecoxib has been shown to be as effective as traditional NSAIDs and may cause fewer endoscopically documented ulcers, but its complete adverse-effect profile is not known. Until the selective COX-2 inhibitors are widely used and more clinical as well as pharmacoeconomic studies are published, the exact role of COX-2 therapy cannot be determined. words: cyclooxygenase, celecoxib, rofecoxib, rheumatoid arthritis, osteoarthritis.     

Coxibs: cyclooxygenase-2 inhibitors

The oxygenating enzyme cyclooxygenase (COX) catalysis the conversion of arachidonic acid to proinflammatory prostaglandins. For many years it was thought that COX is a single enzyme that is present constitutively in most tissues. But in the late 80ies COX activity was found to be increased in inflammatory states with cytokines and bacterial lipopolysaccharides as inducing agents. The expression of the induced COX is inhibited by glucocorticoids which is not the case with the COX known up to then. According to these findings COX exists in two forms, the aminoacid sequences of which are known. The expression of COX-1 is not or only poorly regulated, the prostaglandins produced by it are responsible for the protection of the gastric mucosa, maintenance of normal kidney function and platelet aggregation. COX-2, in contrast, is highly regulated, the prostaglandins produced by this isoenzyme are involved in inflammation, fever and pain but also in the regulation of kidney function. Conventional non-steroidal antiinflammatory drugs (NSAIDs) inhibit both COX-1 and COX-2. The analgesic, antipyretic and antiinflammatory effects of these agents are accounted for by COX-2 inhibition, whereas the toxic effects on the stomach as well as the inhibition of platelet aggregation are attributed to COX-1 inhibition. In search for selective blockers of COX-2, celecoxib and rofecoxib were developed which have an analgetic and antirheumatic potency similar to that of conventional NSAIDs but are associated with significantly fewer adverse gastroduodenal events. The renal toxicity of the selective COX-2 inhibitors is not better than that of the non-selective NSAIDs.     

An update on nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors

Selective inhibitors of the cyclooxygenase-2 enzyme were developed to treat pain and inflammation while reducing the risk of the serious gastrointestinal side effects seen with nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). The results of several clinical trials have demonstrated an apparent increased risk of serious cardiovascular events in patients taking the COX-2-selective inhibitors. Although the risk was observed originally with trials conducted with rofecoxib, it was attributed generally to the entire class of COX-2-selective drugs based on a similar mechanism of action and a hypothesis that predicted the possibility of a prothrombotic effect of the drugs compared with nonselective NSAIDs. Subsequent studies have demonstrated that elevated cardiovascular risk is not limited to the use of COX-2-specific inhibitors. An increase in cardiovascular risk actually has been seen with antiinflammatory drugs of the NSAID class, regardless of whether they are selective or nonselective inhibitors. The US Food and Drug Administration has recommended that all such drugs carry a black box warning for gastrointestinal and cardiovascular risks.     

Review of the selective COX-2 inhibitors celecoxib and rofecoxib: focus on clinical aspects

The selective cyclooxygenase-2 (COX-2) inhibitors celecoxib and rofecoxib were designed to have similar efficacy but less gastrointestinal toxicity than traditional nonsteroidal anti-inflammatory drugs (NSAIDs). Their efficacy has been demonstrated in the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, postoperative dental pain and dysmenorrhea. These agents produce fewer endoscopic ulcers, symptomatic ulcers and gastrointestinal bleeds than traditional NSAIDs; although the absolute benefit is small and the gastropreserving effect is negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Nephrotoxicity and hyptertension remain concerns with COX-2 inhibitors, as they are with traditional NSAIDs. COX-2 inhibitors may be safe alternatives to traditional NSAIDs for patients with aspirin-sensitive asthma.     

Rofecoxib: clinical pharmacology and clinical experience

BACKGROUND: Rofecoxib is a member of a subgroup of nonsteroidal anti-inflammatory drugs (NSAIDs) known as cyclooxygenase-2 (COX-2)-selective inhibitors. It has been studied in adult and elderly patients in a number of painful conditions (primary dysmenorrhea, acute pain after dental and orthopedic surgery, osteoarthritis [OA], and rheumatoid arthritis). OBJECTIVE: This review discusses the clinical pharmacology of and clinical experience with rofecoxib, and the role of COX-2-selective inhibitors in clinical practice. METHODS: Pertinent studies were identified through searches of MEDLINE and EMBASE, as well as the Web sites and proceedings of relevant scientific meetings. RESULTS: Although the published literature is limited, the data indicate that rofecoxib is an effective analgesic agent for the painful conditions in which it has been studied. As a COX-2-selective inhibitor, rofecoxib offers safety advantages over traditional NSAIDs. In clinical trials, gastrointestinal (GI) toxicity, including mucosal damage, perforation, ulcers, and bleeding, occurred significantly less often in healthy volunteers and patients treated with rofecoxib than in those who received NSAIDs such as ibuprofen, naproxen, or diclofenac (all comparisons, P < 0.001). In terms of renal toxicity, rofecoxib does not appear to offer a safety advantage over traditional NSAIDs. Rofecoxib has not been shown to affect platelets (bleeding time and platelet aggregation), unlike traditional NSAIDs. CONCLUSIONS: Rofecoxib is an appropriate choice for patients who do not obtain adequate analgesia with acetaminophen and those who have not obtained adequate analgesia from, cannot tolerate, or are at risk for GI toxicity with traditional NSAIDs. Patients who require chronic analgesic medication (ie, those with OA), including those who take other medications daily for comorbid conditions, may also benefit from the once-daily dosing regimen of rofecoxib.     

Specific COX-2 inhibitors: prospects of therapy with new analgesic and anti-inflammatory substances

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) activity, thereby suppressing the synthesis of proinflammatory prostaglandins. The identification and molecular-biological characterization of an inducible COX isoform (COX-2) in inflammatory cells led to the hypothesis that a selective inhibition of COX-2 would result in relief of inflammation and pain without causing the COX-1-dependent side effects (gastrointestinal ulceration, platelet dysfunction, kidney damage) of conventional NSAIDs. On the basis of data obtained in several laboratories by means of the "human whole blood assay" there is now convincing evidence that none of the currently available NSAIDs is a selective COX-2 inhibitor. Meanwhile, the specific COX-2 inhibitors celecoxib and rofecoxib are being tested worldwide in phase III clinical trials on patients with rheumatoid arthritis and osteoarthritis. However, the simple concept of COX-2 being an exclusively proinflammatory inducible enzyme cannot be upheld any longer. In addition, COX-2 is expressed constitutively in brain, spinal cord and kidney, as well as in numerous other organs. In the present review the perspectives and possible risks of specific COX-2 inhibitors are discussed, as well as additional indications for their implementation (e.g. colon cancer).     

Cyclooxygenase-2 inhibitor celecoxib: a possible cause of gastropathy and hypoprothrombinemia

Gastrointestinal side effects from nonsteroidal anti-inflammatory drugs (NSAIDs) result mainly from inhibition of the enzyme cyclooxygenase (COX)-1; it is responsible for the synthesis of prostaglandin E2, which leads to increased mucosal blood flow, increased bicarbonate secretion, and mucus production, thus protecting the gastrointestinal mucosa. In inflammation, COX-2 is induced, causing synthesis of the prostaglandins in conditions such as osteoarthritis and rheumatoid arthritis. Two NSAIDs (celecoxib and rofecoxib) with very high specificity for COX-2 and virtually no activity against COX-1 at therapeutic doses have been approved for clinical use. In trials of celecoxib and rofecoxib, only 0.02% of patients had clinically significant gastrointestinal bleeding, compared to a 1% to 2% yearly incidence of severe gastrointestinal side effects with NSAIDs. Our patient had arthritis of the hips and chronic atrial fibrillation and was on warfarin therapy for stroke prevention; less than a week after starting celecoxib therapy, gastrointestinal bleeding and hypoprothrombinemia occurred.     

Valdecoxib: a review

BACKGROUND: Traditional nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac, ibuprofen, naproxen, and related agents are nonselective inhibitors of both cyclooxygenase-1 (COX-1) and COX-2, which catalyze prostaglandin synthesis. This inhibition accounts not only for the analgesic, anti-inflammatory, and antipyretic effects of these agents, but also for side effects such as gastric mucosal damage and renal toxicity. Substantial evidence suggests that sparing COX-1 is advantageous for gastric safety. OBJECTIVE: This article reviews available information on the new COX-2-selective inhibitor valdecoxib, including its clinical pharmacology, pharmacokinetics, adverse effects, potential drug interactions, and contraindications and warnings. Results of clinical trials of efficacy and tolerability are summarized. METHODS: Articles for inclusion in this review were identified through searches of PubMed and MEDLINE (1966-December 2002) and International Pharmaceutical Abstracts (1970-December 2002). Search terms included valdecoxib, Bextra, COX-2-selective inhibitors, coxibs, and selective cyclooxygenase inhibitors. The reference lists of identified articles were reviewed for additional publications. Product information was also obtained from the manufacturer of valdecoxib. RESULTS: Fourteen clinical studies involving > 4000 patients have been conducted. Valdecoxib was significantly more effective than placebo in the treatment of adult rheumatoid arthritis, osteoarthritis, pain associated with primary dysmenorrhea, and postoperative pain. Valdecoxib was comparable to naproxen for the treatment of rheumatoid arthritis in 1 study and equivalent to naproxen for the treatment of osteoarthritis in other studies. Three studies found valdecoxib comparable to naproxen sodium for the relief of moderate to severe pain due to primary dysmenorrhea, and others found valdecoxib comparable to oxycodone plus acetaminophen and significantly more effective than rofecoxib for the relief of pain associated with dental surgery (P < 0.05). Four safety studies and 2 reviews of clinical trials documented lower rates of endoscopic gastroduodenal ulcer formation with valdecoxib compared with ibuprofen, naproxen, and diclofenac (P < 0.001 to P < 0.05). Valdecoxib did not inhibit platelet function (bleeding time and platelet aggregation) in healthy adults or in the elderly. Due to the risk of potentially serious skin and allergic reactions, patients who are allergic to sulfa-containing drugs should not take valdecoxib. The drug should be discontinued immediately if rash develops. CONCLUSIONS: In clinical trials, valdecoxib was effective for the treatment of osteoarthritis, rheumatoid arthritis, and moderate to severe pain associated with primary dysmenorrhea. As with the other COX-2-selective inhibitors (celecoxib and rofecoxib), valdecoxib appears to produce less gastrointestinal toxicity than conventional nonselective NSAIDs, although some of the relevant clinical studies have been published only as abstracts. Use of valdecoxib should be reserved for patients at risk for NSAID-induced gastrointestinal problems.     

Relative efficacy of selective COX-2 inhibitors compared with over-the-counter ibuprofen

Non-steroidal anti-inflammatory drugs (NSAIDs) suppress the activity of both isoforms of cyclo-oxygenase (COX). Inhibition of COX-1, the constitutive isoform, is primarily responsible for the adverse gastrointestinal effects of the NSAIDs whereas inhibition of COX-2, the inducible isoform, accounts for their therapeutic effects. COX-2 inhibitors such as celecoxib and rofecoxib appear to be as effective as non-selective NSAIDs in the treatment of chronic inflammatory disease but their analgesic efficacy and their safety at the higher doses required for analgesia are less certain. There is consistent evidence that COX-1 plays a major role in the early pain response following injury and that analgesia is increased when both COX-1 and COX-2 are inhibited simultaneously. Early postoperative nociception may cause hyperalgesia at a later time by a process of central plasticity. In an experimental model of pain, ibuprofen promptly suppresses prostaglandin E2 concentrations whereas celecoxib has no discernible effect until 90-120 minutes postoperatively, when COX-2 activity is induced. Both drugs significantly reduce pain compared with placebo but celecoxib appears to have a slower onset of action. The analgesic effect of ibuprofen is well characterised for acute pain and short-term treatment is well tolerated.     

Cyclooxygenase-2 enzyme inhibitors: place in therapy

Nonsteroidal anti-inflammatory drugs (NSAIDs) play a major role in the management of inflammation and pain caused by arthritis. A new class of NSAIDs that selectively inhibit the cyclooxygenase-2 (COX-2) enzyme has been developed. The first COX-2 inhibitors, celecoxib and rofecoxib, are said to provide therapeutic benefit with less toxicity than traditional NSAIDs. A third COX-2-selective inhibitor, meloxicam, has recently been introduced. COX-2 inhibitors and traditional NSAIDs do not appear to differ significantly in their effectiveness in alleviating pain or inflammation. They have similar gastrointestinal side effects, including abdominal pain, dyspepsia and diarrhea. However, short-term studies show fewer gastrointestinal ulcers in patients treated with COX-2 inhibitors compared with traditional NSAIDs.     

Recent development of selective cyclooxygenase-2 inhibitors

Nonsteroidal anti-inflammatory drugs(NSAIDs) are clinically effective against the inflammatory symptoms of rheumatoid arthritis. Recent attention has been focused on selective cyclooxygenase(COX)-2 inhibitors, a type of NSAID that inhibits a subtype of COX. Because of the different actions of COX-1 and COX-2, selective COX-2 inhibitors were expected to reduce adverse reactions such as gastrointestinal disorders. Various clinical studies have confirmed that the efficacy of COX-2 inhibitors for RA is similar to that of conventional NSAIDs, but they cause fewer severe gastrointestinal disorders. The incidence of complications related to renal dysfunction, such as edema and hypertension, is not different. Patients using selective COX-2 inhibitors have recently been reported to show an increase in thrombotic complications such as myocardial infarction. Therefore, more data on adverse events should be collected in the future from large-scale clinical studies to further clarify the actual value of selective COX-2 inhibitors.     

Clinical data on COX-1 and COX-2 inhibitors: what possible alerts in pharmacovigilance?

Adverse effects of NSAIDs are serious, mainly related to gastrointestinal bleeding, and throughout the world cause about 260,000 hospitalizations and 26,000 deaths a year, but each day at least thirty million patients take NSAIDs. Selective COX-2 inhibitors (i.e. celecoxib, rofecoxib) have demonstrated in clinical trials better gastrointestinal tolerability but their safety in patients with active ulcer, cardiovascular or renal disease has still to be further investigated. When their long-term safety has been established by pharmacovigilance studies they could be prescribed in the at-risk population or for other indications, including pre-term labour, colorectal cancer and Alzheimer's disease, provided they have shown efficacy and safety in controlled trials.