Safety of a cyclooxygenase-2 inhibitor in patients with aspirin-sensitive asthma

Effects of nonselective and selective cyclooxygenase inhibitors on the contractions of isolated bronchial smooth muscle in the horse

We evaluated the effects of nonselective cyclooxygenase (COX)-1/COX-2 inhibitors (acetylsalicylic acid, indomethacin, ibuprofen, flunixin meglumine, phenylbutazone), preferential COX-2 inhibitors (diclofenac, meloxicam, carprofen), selective COX-1 inhibitor (SC-560), and selective COX-2 inhibitors (celecoxib, firocoxib, parecoxib) on the contractions of isolated bronchi induced by electrical field stimulation (EFS). Bronchial rings, obtained from lungs of slaughtered horses, were put in isolated organ baths, and the mechanical activity was measured by means of isotonic transducers. Electrical Field Stimulation was applied to the preparations, and the effects of drugs on the amplitude of evoked contractions were measured. Nonselective COX inhibitors did not modify EFS-induced contractions to a relevant degree, except indomethacin which caused a concentration-dependent decrease of the contraction amplitude. Conversely, preferential COX-2 inhibitors enhanced the contractions in a concentration-related fashion, whilst the selective COX-1 inhibitor reduced them. Among selective COX-2 inhibitors, parecoxib increased EFS-evoked contractions whereas celecoxib and firocoxib were ineffective. These results suggest that the inhibition of prostanoid synthesis does not modify the electrical field-stimulated contractions of isolated horse bronchi. Since EFS-induced contractions of horse bronchi were previously shown to be of full cholinergic nature, the increase caused by diclofenac, meloxicam, carprofen, and parecoxib could be due to an inhibition of acetylcholinesterase; in accordance, these drugs potentiated exogenous acetylcholine-induced but not carbachol-induced bronchial contraction. Indomethacin and SC-560 might instead decrease bronchial contractions by inhibiting calcium currents. Clinical use of meloxicam and carprofen in horses with bronchial hyper-responsiveness requires caution for a potential risk of causing adverse effects due to bronchoconstriction.

Aspirin exacerbated respiratory disease: Current topics and trends

Aspirin-exacerbated respiratory disease is a chronic and treatment-resistant disease, characterized by the presence of eosinophilic rhinosinusitis, nasal polyposis, bronchial asthma, and nonsteroidal anti-inflammatory drugs hypersensitivity. Alterations in arachidonic acid metabolism may induce an imbalance between pro-inflammatory and anti-inflammatory substances, expressed as an overproduction of cysteinyl leukotrienes and an underproduction of prostaglandin E2. Although eosinophils play a key role, recent studies have shown the importance of other cells and molecules in the development of the disease like mast cells, basophils, lymphocytes, platelets, neutrophils, macrophages, epithelial respiratory cells, IL-33 and thymic stromal lymphopoietin, making each of them promissory diagnostic and treatment targets. In this review, we summarize the most important clinical aspects of the disease, including the current topics about diagnosis and treatment, like provocation challenges and aspirin desensitization. We also discuss recent findings in the pathogenesis of the disease, as well as future trends in diagnosis and treatment, including monoclonal antibodies and a low salicylate diet as a treatment option.

Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by the triad of asthma, sinonasal polyposis, and aspirin intolerance. The hallmark of the disease is baseline overproduction of cysteinyl leukotrienes via the 5-lipoxygenase pathway, exacerbated by ingestion of aspirin. Patients with AERD have high rates of recidivistic polyposis following sinus surgery, although the improvement in quality of life following surgery is similar to aspirin-tolerant patients. The diagnosis is secured by a positive aspirin provocation test, usually administered by a medical allergist. Aspirin therapy is a unique treatment consideration for patients with AERD.

Use of nonsteroidal anti-inflammatory drugs in patients with aspirin hypersensitivity : safety of cyclo-oxygenase-2 inhibitors

This article provides information on the pathogenesis of aspirin hypersensitivity, cross-sensitivity, and cross-tolerance of different NSAIDs in patients with respiratory types of reactions. Hypersensitivity to aspirin may affect 5-20% of patients with chronic asthma and an unknown fraction of patients with chronic urticaria-angioedema. These patients develop cross-reactions to other, chemically non-related, NSAIDs with strong inhibitory activity towards cyclo-oxygenase (COX)-1 (e.g. indomethacin, naproxen, ketoprofen). Avoidance of aspirin and all cross-reacting NSAIDs as well as education of patients are crucial. As an alternative antipyretic or analgesic drug, aspirin-sensitive asthmatic patients may take acetaminophen (paracetamol) in low or moderate doses (<1000mg). Preferential COX-2 inhibitors (nimesulide, meloxicam) are tolerated by the majority but not all hypersensitive patients. Selective COX-2 inhibitors (celecoxib and rofecoxib [withdrawn from the market]) are well tolerated by almost all aspirin-sensitive asthmatic patients. In patients with coronary artery disease requiring treatment with aspirin, desensitization to aspirin may be an alternative approach. Thus, for the majority of patients with asthma and hypersensitivity to aspirin or other NSAIDs, an alternative anti-inflammatory drug can be found. However, in each individual case physicians must consider the choice of an alternative NSAID carefully.

Short-term use of nonsteroidal anti-inflammatory drugs and adverse effects: An updated systematic review

BACKGROUND

In this article, the authors examine the available scientific evidence regarding adverse effects of short-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). Short-term use was defined as 10 days or fewer.

METHODS

The authors reviewed randomized controlled clinical trials and cohort and case-controlled clinical studies published between 2001 and June 2015 in which the investigators reported on the safety of nonselective cyclooxygenase inhibitors and of cyclooxygenase-2 selective inhibitor NSAIDs.

RESULTS

The systematic review process according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines allowed the authors to identify 40 studies that met the inclusion criteria.

CONCLUSIONS

On the basis of the available scientific evidence, NSAIDs may be considered relatively safe drugs when prescribed at the most effective dose and for the shortest duration of time, which was defined to be 10 days or fewer.

PRACTICAL IMPLICATIONS

Although the US Food and Drug Administration recommends the use of NSAIDs beyond 10 days to be accompanied by a consultation with a health care provider, the use of NSAIDs may be considered relatively safe when prescribed at the most effective dose and for the shortest duration of time, which was defined as 10 days or fewer. Exceptions would be for patients at risk of developing NSAID-exacerbated respiratory disease, patients with prior myocardial infarction who are receiving antithrombotic therapy, patients with asthma, and patients with a history of renal disease.

Pilot study of the use of Yin Qiao San in children with conventional antipyretic hypersensitivity

BACKGROUND

Children with a diagnosis of cross-reactive hypersensitivity to both paracetamol and nonsteroidal anti-inflammatory drugs are limited in their choice of antipyretics.

OBJECTIVE

The aim of this pilot study is to evaluate the feasibility of using a Chinese proprietary medicine, Yin Qiao San (YQS), for fever relief.

METHODS

A single centre, open label, prospective clinical trial exploring the tolerability and feasibility of using YQS for fever relief in children who are unable to use conventional antipyretic medications. Children between 1-18 years of age with hypersensitivity to multiple antipyretics were recruited. Eligible participants underwent an oral provocation test with YQS. Children who passed the oral provocation test were instructed to take a prescribed dose of YQS when the temperature was >38.0℃ and continued till the fever settled. Time taken for fever resolution and any adverse events were collected.

RESULTS

A total of 21 children, mean age 10.7 years, had a diagnosis of paracetamol and ibuprofen hypersensitivity. All except one patient successfully tolerated an oral challenge of YQS. Of the 88 doses of YQS taken for fever over 38.0℃, 16 (18%) had documented temperature reduction 2 hours after ingestion and 30 (34%) had documented temperature reduction 4 hours after ingestion. There were 2 reports of urticaria after YQS use which were attributed to flare of recurrent spontaneous urticaria during the illness. None of the patients developed symptoms of circulatory compromise or respiratory distress.

CONCLUSION

YQS is generally well tolerated in patients with paracetamol and ibuprofen hypersensitivity.

Tolerance to etoricoxib in children with nonsteroidal anti-inflammatory drug hypersensitivity

Background

Cyclooxygenase-2 (COX-2) inhibitors have been found to be safe alternatives in adults with cross-intolerant hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). However they are usually not prescribed in children and there is little information about their tolerance in the pediatric age group.

Objective

This study aims to evaluate the tolerance to etoricoxib in children with hypersensitivity to multiple antipyretics.

Methods

A retrospective case series of children diagnosed with hypersensitivity reactions to NSAIDs and/or paracetamol who underwent a drug provocation test (DPT) with etoricoxib. Information on atopy, family history of allergic diseases, and medication usage was collected. Outcomes of the DPTs and tolerance to etoricoxib were also evaluated.

Results

A total of 24 children, mean age 13.5 years, had a diagnosis of cross-intolerant hypersensitivity to NSAIDs and/or paracetamol. All except one patient successfully tolerated an oral challenge with etoricoxib. Of those who passed the DPT, the majority continued to use etoricoxib with no problems. It was found to be moderately effective in reducing fever and pain.

Conclusion

Etoricoxib can be used as a safe alternative in older children with hypersensitivity to multiple antipyretics.

Tolerance to alternative cyclooxygenase-2 inhibitors in nonsteroidal anti-inflammatory drug hypersensitive patients

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) frequently cause adverse drug reactions. Many studies have shown that drugs which selectively inhibit the cyclooxygenase-2 enzyme (COX-2) are safe alternatives in the majority of patients. However, hypersensitivity reactions to COX-2 inhibitors have been published. Hardly any data are available regarding the safety of alternatives in case of COX-2 inhibitor hypersensitivity. We aimed to investigate the tolerance to COX-2 inhibitors in patients with non-selective NSAID hypersensitivity. Furthermore, in COX-2 hypersensitive patients tolerance of a second COX-2 inhibitor was investigated.

METHODS

We retrospectively analyzed 91 patients with proven non-selective NSAID hypersensitivity that underwent oral challenges with a COX-2 inhibitor. Patients with intolerance to the first challenged COX-2 inhibitor received a second challenge with a different COX-2 inhibitor.

RESULTS

19 out of 91 (21%) patients had a positive reaction to the first oral challenge with a COX-2 inhibitor. 14 of them underwent a second challenge with a different COX-2 inhibitor and 12 (86%) did not react.

CONCLUSIONS

A relatively high percentage (21%) of the non-selective NSAID hypersensitive patients did not tolerate a COX-2 inhibitor and oral challenge is advised prior to prescription of a COX-2 inhibitor. For the majority of patients reacting to a COX-2 inhibitor an alternative can be found.

COX inhibitors for airway inflammation

INTRODUCTION

The cyclooxygenase (COX) enzyme, which is responsible for the production of prostaglandins (PGs), key mediators of inflammation, may have the potential to become an attractive target for anti-inflammatory therapy. COX catalyzes the conversion of arachidonic acid (AA) into PGs, which play a significant role in disease. PGs are lipid mediators of central importance in the regulation of inflammation and smooth muscle tone. Airway-resident inflammatory cells release PGs: PGD2 and PDF2a amplify smooth muscle contraction and airway inflammation. Following its conversion from membrane phospholipids by phospholipase, AA enters the prostanoid pathway via COX, which catalyzes the conversion of AA to PGH2. PGH2 is then converted to biologically active PGs by cell-specific PG synthases. As COX is the rate limiting step in the PG pathway, the regulation of this enzyme is of critical importance in PG production.

AREAS COVERED

This review addresses the opportunities and challenges of COX inhibitors as therapeutic targets in airway inflammation. The review covers literature from the past 20 years.

EXPERT OPINION

Current literature favors COX inhibitors as potential targets for airway diseases. However, from the information available, it is not clear whether the COX enzyme by itself can serve as a target in drug development for asthma and COPD. Therefore, additional research is required to elucidate the mechanisms of action of COX metabolites before it can be considered as a target.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Chronic obstructive pulmonary disease and neutrophil infiltration: role of cigarette smoke and cyclooxygenase products

Cigarette smoke is the main cause of chronic obstructive pulmonary disease (COPD), where it can contribute to the observed airway inflammation. PGE(2) is produced within human airways, and both pro- and anti-inflammatory activities have been reported. We quantitated PGE(2) concentrations in induced sputum supernatants from different groups of subjects and correlated the obtained values to neutrophil infiltration as well as to the expression of cyclooxygenase-2 (COX-2). Cigarette smoke extract (CSE) was used to evaluate the effect of smoking on COX-2 and PGE(2) receptor expression as well as on PGE(2) release in neutrophils and alveolar macrophages (AM) obtained from normal donors. The effects of PGE(2) and of PGE receptor agonists and antagonists were evaluated on the adhesion of neutrophil to a human bronchial epithelial cell line (16HBE). PGE(2) levels, COX-2 expression, and neutrophil infiltration were significantly higher in normal smokers and COPD smokers (P < 0.0001) compared with controls and COPD former smokers. Induced sputum supernatant caused neutrophil adhesion to 16HBE that was significantly reduced, in COPD smokers only, by PGE(2) immunoprecipitation. In vitro experiments confirmed that CSE increased PGE(2) release and COX-2 and PGE(2) receptor expression in neutrophils and AM; PGE(2) enhanced the adhesion of neutrophils to 16HBE, and a specific E-prostanoid 4 (EP(4)) receptor antagonist blunted its effect. These results suggest that CSE promote the induction of COX-2 and contributes to the proinflammatory effects of PGE(2) in the airways of COPD subjects.

Management options for patients with aspirin and nonsteroidal antiinflammatory drug sensitivity

OBJECTIVE

To evaluate and provide management strategies for patients with aspirin or nonselective nonsteroidal antiinflammatory drug (NSAID) sensitivity.

DATA SOURCES

Literature retrieval was accessed through MEDLINE (1966-March 2007) using the terms acetaminophen, aspirin, antiinflammatory agents nonsteroidal, urticaria, angioedema, asthma, leukotriene antagonists, desensitization, and tacrolimus. Article references retrieved were hand-searched for other relevant articles.

STUDY SELECTION AND DATA EXTRACTION

All studies published in English were evaluated. Studies, review articles, and commentaries on aspirin-induced asthma and aspirin- or NSAID-induced urticaria/angioedema were included in the review.

DATA SYNTHESIS

Aspirin sensitivity is most often manifested as respiratory reactions (eg, bronchospasm, profuse rhinorrhea, conjunctival injection) or urticaria/angioedema. The primary mechanism is believed to be inhibition of the cyclooxygenase 1 (COX-1) enzyme; as such, patients with aspirin sensitivity often display cross-reactions to nonselective NSAIDs that inhibit the COX-1 enzyme. Management strategies include avoidance of aspirin and cross-reacting nonselective NSAIDs. However, desensitization to aspirin is a viable option for patients with aspirin-induced respiratory reactions, especially for those who require aspirin for thromboembolic prophylaxis. Aspirin desensitization is maintained indefinitely with a daily aspirin dose. There is limited evidence of the use of leukotriene modifiers in preventing aspirin-induced asthma. COX-2 selective NSAIDs, especially in patients with aspirin-induced asthma, have not been found to cross-react. However, approximately 4% of patients with a history of aspirin-induced skin reactions may experience a cutaneous reaction following a challenge to a COX-2 selective NSAID. Since acetaminophen is a weak inhibitor of the COX-1 enzyme, patients with aspirin-induced asthma should not take more than 1000 mg of acetaminophen in a single dose.

CONCLUSIONS

Management of patients with aspirin/NSAID sensitivity includes avoidance of aspirin/nonselective NSAIDs, use of COX-2 selective NSAIDs, acetaminophen in doses less than 1000 mg, and desensitization. The role of leukotriene modifiers requires further study before they can be recommended for patients.

The Prevalence of Samter's Triad in Patients Undergoing Functional Endoscopic Sinus Surgery

We conducted a retrospective study to determine the prevalence of Samter's triad (nasal polyps, asthma, and aspirin sensitivity) in 208 consecutively presenting patients who had undergone functional endoscopic sinus surgery (FESS) for chronic rhinosinusitis from September 2001 through August 2003. Overall, Samter's triad was found in 10 patients (4.8%); subgroup analyses showed that the prevalence of Samter's triad was 5.9% in adults, 9.4% in patients with nasal polyps alone, 16.9% in patients with asthma alone, and 25.6% among patients with both polyps and asthma. On average, patients with Samter's triad had undergone approximately 10 times as many previous FESS procedures as had the patients without Samter's triad (mean: 5.2 vs. 0.53; p < 0.001). In addition to Samter's triad, four other factors were independently and significantly associated with a higher number of previous FESS procedures: nasal polyps alone, asthma alone, both polyps and asthma, and cystic fibrosis alone. Finally, at 6 months following their most recent surgery, patients with Samter's triad had significantly higher rates of symptom recurrence (nasal obstruction, facial pain, postnasal drip, and anosmia) and a recurrence of nasal polyps.

Allergic reactions to nonsteroidal anti-inflammatory drugs: is newer better?

In clinical practice, physicians may find it difficult to recognize the differences between allergic and pseudo-allergic reactions to nonsteroidal anti-inflammatory drugs (NSAIDs) and to manage each type of reaction. This paper reviews all the information presently available in order to clarify main problems related to NSAID reactions and to highlight key strategies to handle these reactions.

Tolerance to coxibs in patients with intolerance to non-steroidal anti-inflammatory drugs (NSAIDs): a systematic structured review of the literature

Adverse events triggered by non-steroidal anti-inflammatory drugs (NSAIDs) are among the most common drug-related intolerance reactions in medicine; they are possibly related to inhibition of cyclooxygenase-1. Coxibs, preferentially inhibiting cyclooxygenase-2, may therefore represent safe alternatives in patients with NSAID intolerance. We reviewed the literature in a systematic and structured manner to identify and evaluate studies on the tolerance of coxibs in patients with NSAID intolerance. We searched MEDLINE (1966–2006), the COCHRANE LIBRARY (4th Issue 2006) and EMBASE (1966–2006) up to December 9, 2006, and analysed all publications included using a predefined evaluation sheet. Symptoms and severity of adverse events to coxibs were analysed based on all articles comprising such information. Subsequently, the probability for adverse events triggered by coxibs was determined on analyses of double-blind prospective trials only. Among 3,304 patients with NSAID intolerance, 119 adverse events occurred under coxib medication. All adverse events, except two, have been allergic/urticarial in nature; none was lethal, but two were graded as life-threatening (grade 4). The two non-allergic adverse events were described as a grade 1 upper respiratory tract haemorrhage, and a grade 1 gastrointestinal symptom, respectively. In 13 double-blind prospective studies comprising a total of 591 patients with NSAID intolerance, only 13 adverse reactions to coxib provocations were observed. The triggering coxibs were rofecoxib (2/286), celecoxib (6/208), etoricoxib (4/56), and valdecoxib (1/41). This review documents the good tolerability of coxibs in patients with NSAID intolerance, for whom access to this class of drugs for short-term treatment of pain and inflammation is advantageous.

The role of COX-2 inhibitors in the treatment of postoperative pain

Postoperative pain requires treatment not only to provide comfort to patients but also to improve postoperative outcome. Anti-inflammatory compounds are an important component of multimodal analgesia in the postoperative period. The newer cyclooxygenase (COX)-2 inhibitors are as effective as classical nonsteroidal anti-inflammatory drugs (NSAIDs) in this setting. However, COX-2 inhibitors offer a number of advantages over NSAIDs when used to treat postoperative pain. These include a reduced incidence of gastrointestinal ulceration and no inhibitory effect on platelet function and thereby a reduced risk of blood loss. Other benefits are less impairment of bone healing and no induction of bronchospasm in patients with aspirin-sensitive asthma. Increased cardiovascular thromboembolic events by COX-2 inhibitors have been reported after coronary artery bypass graft surgery only, but in general, surgery studies the incidence of such complications was comparable to placebo. Overall, COX-2 inhibitors offer a number of advantages over classical NSAIDs in the postoperative pain setting, but require the same caution with regard to renal effects.

New Evidence of H1-Receptor Independent COX-2 Inhibition by Fexofenadine HCl in vitro

BACKGROUND/AIMS

Fexofenadine HCl (FEX) has previously been shown to have anti-inflammatory properties in relieving nasal congestion in allergic rhinitis. The objective of this study was to further elucidate the mechanism of action behind the anti-inflammatory properties of FEX in addition to its H(1)-receptor antagonism.

METHODS

The effects of two antihistamines, FEX and loratadine (LOR), were investigated on cyclooxygenase (COX)-1 and -2 enzymes in vitro. FEX (10(-9)-10(-3) mol/l) and LOR (10(-9)-10(-4) mol/l) were incubated with arachidonic acid in a COX screening assay with either ovine COX-1 or COX-2 or human COX-2. COX-2 enzyme inhibitory activity for the antihistamines was compared with the known selective COX-2 inhibitor DuP-679.

RESULTS

High concentrations of FEX (10(-3) mol/l) significantly inhibited arachidonic acid-mediated ovine COX-1 activity, but low concentrations had no effect. Low concentrations of FEX (10(-8) mol/l) inhibited ovine COX-2 activity, and this inhibition decreased with increasing concentrations. The inhibition of COX-2 activity by FEX was similar to that seen with the selective COX-2 inhibitor, DuP-679. Conversely, LOR inhibited COX-1 activity at low concentrations (10(-8) mol/l), but had little inhibitory effect on COX-1 at high concentrations. LOR (10(-5) mol/l) markedly stimulated COX-2 activity.

CONCLUSION

FEX showed selective arachidonic acid-mediated COX-2 inhibitory enzyme activity, which differed markedly from the COX inhibitory enzyme activity of LOR. This selective COX-2 inhibitor activity by FEX may contribute to its anti-inflammatory properties in relieving nasal congestion in allergic rhinitis.

Safety of etoricoxib, a specific cyclooxygenase-2 inhibitor, in asthmatic patients with aspirin-exacerbated respiratory disease

BACKGROUND

Treatment of rheumatic conditions is limited in patients with asthma owing to concerns of nonsteroidal anti-inflammatory drugs potentially provoking asthma. Cross-sensitivity to all anti-inflammatory drugs that inhibit cyclooxygenase enzymes occurs in these individuals.

OBJECTIVES

To study the safety of etoricoxib, a specific cyclooxygenase-2 inhibitor, and to determine whether it cross-reacts with asthma in patients with aspirin-exacerbated respiratory disease (AERD).

METHODS

This study included 77 patients who had experienced asthma induced by aspirin and at least 1 other nonsteroidal anti-inflammatory drug. Baseline evaluation included blood pressure measurement, nasal examination, spirometry, and peak expiratory flow rate measurement. Patients were given placebo the first day and then were challenged with once-daily etoricoxib in 3 different doses: 60 mg on day 2, 90 mg on day 3, and 120 mg on day 4. If no evidence of intolerance was seen, each patient was rechallenged with 60 or 90 mg of etoricoxib once daily (according to the rheumatic condition) 7 days later. Reassessment of the baseline measurements was performed daily from day 1 to day 4 after the initial challenge, on day 7 after rechallenge, and after 1 month of drug intake. If the patient developed any mucosal or skin reaction, hypotension, upper or lower airway obstruction, conjunctival reaction, or laryngeal edema during the challenge test, it was considered a positive response.

RESULTS

Etoricoxib was well tolerated, without any signs of immediate or delayed hypersensitivity in aspirin- and nonsteroidal anti-inflammatory drug-induced asthmatic patients. None of 77 study patients experienced any symptoms or developed dyspnea, change in nasal examination, significant variation in peak expiratory flow rate greater than 20%, or decline in forced expiratory volume in 1 second greater than 15% during etoricoxib challenge. The exact 1-sided confidence interval for the probability of etoricoxib inducing cross-reactions in patients with AERD was 0% to 2%.

CONCLUSIONS

These results confirm the lack of cross-reactivity between specific cyclooxygenase-2 inhibitors and aspirin in AERD. Etoricoxib was safe for treating inflammation in patients with AERD.

[Critical reevaluation of cyclooxygenase two inhibitors in perioperative pain therapy]

A significant increase in thromboembolic events (i.e. myocardial infarction and stroke) was demonstrated in multicenter studies after several months of treatment with cyclooxygenase 2 (cox-2) inhibitors. In February 2005, the European medical agencies (EMEA) substantially increased the number of contraindications for all cox-2 inhibitors. They are now contraindicated for patients with coronary artery disease. Furthermore, 2 out of 6 cox-2 inhibitors have been withdrawn from the market. In this review, the current state of knowledge on the use of cox-2 inhibitors in perioperative pain therapy is summarized: i) they are equally as potent as other non-opioid analgesics, ii) they decrease opioid consumption, iii) a reduction in postoperative nausea and vomiting (PONV) has not been adequately demonstrated. Regarding side-effects, it can be concluded that i) the incidence of thromboembolic events is increased in patients undergoing coronary artery bypass surgery, ii) perioperative blood loss is not affected, iii) ulcer formation is not promoted, iv) the risk for acute renal failure is probably increased to the same extent as for NSAIDs and v) severe bronchospasm can be triggered in patients with asthma and chronic obstructive pulmonary disease (COPD).

The safety of rofecoxib

Like all COX-2 inhibitors, rofecoxib has been developed based on the hypothesis that at comparable therapeutic efficacy, it would have a better safety and tolerability profile than conventional NSAIDs. The Vioxx GI Outcomes Research trial has demonstrated that rofecoxib is indeed safer for the gastrointestinal tract than NSAIDs. However, this study has also raised questions regarding the cardiovascular safety of rofecoxib. Thereafter, several epidemiological and case-control studies have reinforced the association between rofecoxib and a higher risk of cardiovascular events. However, at this time, no prospective controlled study is available to conclude definitively on this issue. Several pathogenic mechanisms are evoked to explain why rofecoxib increases the cardiovascular risk. These include the development of a prothrombotic state, a sodium retention and an increase in systemic blood pressure. Recently, new evidence have become available indicating that rofecoxib indeed increases the number of thrombo-embolic events. These data have resulted in the complete withdrawal of rofecoxib from the market. Was it scientifically reasonable to withdraw rofecoxib rather than to adapt its label? Is the safety profile of rofecoxib really much worse than that of aspirin or other traditional NSAIDs? The main consequence of this withdrawal is a considerable threat on the entire class of selective COX-2 inhibitors without a clear evaluation of the balance between the risks and benefits of these compounds.

Pathogenesis and management of aspirin-intolerant asthma

In 2-23% of adults with asthma, and rarely in children with asthma, aspirin (acetylsalicylic acid) and non-steroidal anti-inflammatory drugs (NSAIDs) cause asthma exacerbations. Within 3 hours of ingestion of aspirin/NSAIDs, individuals with aspirin-intolerant asthma (AIA) develop bronchoconstriction, often accompanied by rhinorrhea, conjunctival irritation, and scarlet flush. In severe cases, a single therapeutic dose of aspirin/NSAIDs can provoke violent bronchospasm, loss of consciousness, and respiratory arrest. In order to diagnose AIA, oral, inhaled, nasal or intravenous aspirin challenge tests are performed in facilities where experienced physicians are present and emergency treatment is available. The exact differences in the pathogenesis of AIA and other types of asthma are not fully understood. The interference of aspirin/NSAIDs with arachidonic acid metabolism in the lungs plays an important role in the mechanism of AIA; inhibition of cyclo-oxygenase is accompanied by overproduction of cysteinyl leukotrienes (cys-LTs). It has been proposed that overproduction of cys-LTs, together with removal by aspirin/NSAIDs of the 'brake' imposed by the bronchodilator prostaglandin E2, may cause an asthma attack in patients with AIA. Development of a suitable animal model to investigate the pathogenesis of AIA would help to clarify this question. Although it is still controversial whether leukotriene modifiers are more effective in patients with AIA compared with other types of asthma, because LT plays an important role in the pathogenesis of AIA, leukotriene modifiers are the preferred medication for the long-term control of AIA. Add-on efficacy of leukotriene modifiers has been confirmed in patients with AIA already treated with inhaled corticosteroids. However, this does not mean that aspirin/NSAIDs can be safely taken by aspirin-sensitive patients treated with leukotriene modifiers. To prevent attacks of AIA, sensitive patients should avoid the use of aspirin/NSAIDs or use selective cyclo-oxygenase 2 inhibitors when required. When patients with AIA need aspirin for specific situations they should receive aspirin desensitization therapy or treatment with selective cyclo-oxygenase 2 inhibitors.

Clinical implications of cyclo-oxygenase-2 inhibitors for acute dental pain management: benefits and risks

BACKGROUND; Cyclo-oxygenase-2 inhibitors (COX-2i) demonstrate analgesic efficacy for patients who require gastrointestinal safety. The authors discuss the potential benefits and risks of these novel, but expensive, analgesics when used in dentistry.

METHODS

The authors conducted a MEDLINE search focused on the subject headings of common analgesic drugs and COX-2i, using peer-reviewed journals limited to the English language. They selected for review 127 articles that met the criteria. They also tried to identify any randomized controlled trials pertinent to dentistry and indicative of evidence-based medicine. RESULTS. When comparing COX isoforms (COX-1 and COX-2), the authors found that overlapping and mutually exclusively properties coexist. COX-2i originally were developed to minimize interference with the gastroprotective properties of the COX-1 isoform, while selectively preventing prostanoid synthesis expressed solely at sites of bodily trauma or other inflammation. COX-2i were found to provide pain relief equal to or slightly exceeding that offered by many mild narcotics. They may avoid some of the serious side effects that can occur with even short-term use of nonselective nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

The pharmacodynamics of COX-2i reveal an agent that includes analgesic, anti-inflammatory and gastroprotective properties but also allows for an undesirable disruption of the delicate hemodynamic balance.

CLINICAL IMPLICATIONS

Symptomatic and asymptomatic gastroparietic patients who do not have severe cardiovascular, cerebral or renal ischemic disease benefit from use of COX-2i. Long-term use of these agents in medically compromised patients may prove disastrous.

Immediate-type allergy to drugs and related compounds: evaluation and management

Adverse drug reactions (ADR) constitute a major health issue in outpatient and inpatient clinical settings. An allergic drug reaction is an immunologically mediated adverse drug reaction that exhibits specificity and recurrence on re-exposure to the offending and/or cross-reactive compound(s). Diagnosis of drug allergy is difficult, as a broad spectrum of different drugs can elicit various immune-mediated diseases with distinct (sometimes unclear) pathomechanism, the exact structure (epitope) that causes the reaction is frequently unknown, the presence of an in vitro or in vivo test results might not be predictive of a clinical situation, and the gold standard or reference test for diagnosis, the drug challenge, is a complicated and sometimes dangerous endeavour. Nevertheless, during the past few years serious attempts have been made to standardise and validate in vitro and in vivo techniques for the diagnosis of drug allergy. New techniques, e.g. flow-assisted analysis of in vitro basophil activation, are replacing older ones like histamine release for immediate-type hypersensitivity reactions. However, additional comprehensive studies are required to further validate the technique and allow its entrance in mainstream diagnostic use, particularly for non-IgE-mediated hypersensitivity. This review attempts to summarize the major causes of immediate hypersensitivity reactions to drugs and related compounds. Special attention is paid to the diagnostic and therapeutic management of this common iatrogenic complication.

Early presentation with angioedema and urticaria in cross-reactive hypersensitivity to nonsteroidal antiinflammatory drugs among young, Asian, atopic children

OBJECTIVE

Nonsteroidal antiinflammatory drugs (NSAIDs), mainly ibuprofen, are used extensively among children as analgesic and antipyretic agents. Our initial survey in the Kendang Kerbau Children's Hospital in Singapore showed NSAIDs to be the second most common adverse drug reaction-causing medications among children of Asian descent. We attempted to characterize the clinical and epidemiologic profile of NSAID reactions in this group of patients.

METHODS

A retrospective case series from a hospital-based pediatric drug allergy clinic was studied. A diagnosis of NSAID hypersensitivity was made with a modified oral provocation test. Atopy was evaluated clinically and tested with a standard panel of skin-prick tests. We excluded from analysis patients with any unprovoked episodes of urticaria and/or angioedema, patients < 1 year of age, and patients who refused a diagnostic challenge test.

RESULTS

Between March 1, 2003, and February 28, 2004, 24 patients, including 14 male patients (58%) and 18 Chinese patients (75%), with a mean age of 7.4 years (range: 1.4-14.4 years), were diagnosed as having cross-reactive NSAID hypersensitivity. A family history consistent with NSAID hypersensitivity was elicited for 17% of patients. None of the patients reported any episodes of angioedema/urticaria unrelated to NSAIDs. The median cumulative reaction-eliciting dose was 7.1 mg/kg. Facial angioedema developed for all patients (100%) and generalized urticaria for 38% of challenged patients, irrespective of age. There was no circulatory compromise, but respiratory symptoms of tachypnea, wheezing, and/or cough were documented for 42% of patients. A cross-reactive hypersensitivity response to acetaminophen was documented for 46% of our patients through their history and for 25% through diagnostic challenge. Compared with patients with suspected adverse drug reactions to antibiotics, patients in the NSAID group were older (7.4 vs 4.8 years) and more likely to have a diagnosis of asthma (odds ratio: 7.5; 95% confidence interval: 3.1-19).

CONCLUSIONS

Early presentations of facial angioedema and urticaria are key features of dose- and potency-dependent, cross-reactive reactions to NSAIDs in a subpopulation of young, Asian, atopic children. Significant overlap with acetaminophen hypersensitivity, especially among very young patients, for whom the use of a cyclooxygenase-2-specific medication may not be feasible, severely limits options for medical antipyretic treatment.

Adverse drug reactions to nonsteroidal anti-inflammatory drugs, COX-2 inhibitors and paracetamol in a paediatric hospital

AIMS

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) in children has rapidly escalated over the last 5 years in Australia. This is primarily as a result of the availability of ibuprofen as an over-the-counter preparation. Several recent, significant adverse drug reactions (ADRs) to NSAIDs, at the Royal Children's Hospital (RCH) in Melbourne, Australia prompted review of all of the RCH reactions reported to these agents over 5 years.

METHODS

The ADR programme documents both spontaneously reported ADRs and ADRs identified by discharge coding. For this study, reported reactions to aspirin, celecoxib, ibuprofen, indomethacin, naproxen, paracetamol and rofecoxib, for the previous 5-year period, were retrieved from the hospital ADR database.

RESULTS

Nineteen reports of ADRs to NSAIDs and six to paracetamol, in patients aged from 4 months to 22 years (median 10 years) were identified. Reactions were predominantly rash (n = 10), gastrointestinal (n = 5) and respiratory (n = 4) side-effects. These included reports of haematemesis with both celecoxib and ibuprofen. One patient died of severe acute exacerbation of asthma following initiation of rofecoxib.

CONCLUSION

NSAID exposures are a significant cause of morbidity in children. Both nonselective NSAIDs and the newer COX-2 inhibitors were associated with significant drug reactions. The overall severity of these ADRs highlights the need for vigilant surveillance of ADRs in paediatrics, including both established and newer agents.

Pathway-oriented profiling of lipid mediators in macrophages

Macrophages produce various kinds of lipid mediators including eicosanoids and platelet-activating factor. Since they are produced from common precursors, arachidonic acid-containing phospholipids, regulations of metabolic pathways underlie the patterning of lipid mediator production. Here, we report a pathway-oriented profiling strategy of lipid mediators by a newly developed multiplex quantification system. We profiled mouse peritoneal macrophages in different activation states. The analysis of kinetics revealed the differences in the production time course of various lipid mediators, which also differed by the macrophage types. Scatterplot matrix analysis of the inhibitor study revealed correlations of lipid mediator species. The changes of these correlations provided estimates on the effects of lipopolysaccharide priming. We also found a highly linked production of 11-hydroxyeicosatetraenoic acid and prostaglandin E2, implying the in vivo property of cyclooxygenase-mediated 11-hydroxyeicosatetraenoic acid production. The present approach will serve as a strategy for understanding the regulatory mechanism of lipid mediator production.

Role of cyclooxygenase-2 inhibitors in postoperative pain management

Cyclooxygenase (COX)-2 inhibitors are as efficacious as nonselective nonsteroidal anti-inflammatory drugs for the treatment of postoperative pain but have the advantages of a better gastrointestinal side-effect profile as well as a lack of antiplatelet effects. There have been recent concerns regarding the cardiovascular side effects of COX-2 inhibitors. Nonetheless, they remain a valuable option for postoperative pain management. The pharmacology of these agents and available studies are reviewed.

Angioedema associated with aspirin and rofecoxib

OBJECTIVE

To report the probable association of angioedema with aspirin therapy and the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib.

CASE SUMMARY

A 44-year-old white woman, previously tolerant to aspirin and other nonsteroidal antiinflammatory drugs (NSAIDs), developed angioedema of the lips after ingesting two 325-mg aspirin tablets during one day. The reaction occurred 3 hours after taking the second aspirin and resolved within 3 hours. Two weeks later, the patient took a 25-mg rofecoxib tablet for a sore throat, and she developed angioedema 5(1/2) hours later. Although the woman took 50 mg of diphenhydramine, the swelling did not subside. She repeated the diphenhydramine dose in the evening and, by noon the next day, 26(1/2) hours after the angioedema began, it was resolved. The patient's internist prescribed an epinephrine auto-injector and advised her to consult an allergist. With skin testing and oral rechallenge with aspirin, but not rofecoxib, the allergist determined the cause of the reactions to be aspirin-induced angioedema and selective COX-2 inhibitor intolerance. The Naranjo probability scale indicated that aspirin was a highly probable cause and rofecoxib was a probable cause of this patient's angioedema.

DISCUSSION

Aspirin-induced angioedema and NSAID intolerance have been well documented. There are reports of both tolerance and intolerance to selective COX-2 inhibitors in patients with documented allergy-like reactions to aspirin and NSAIDs.

CONCLUSIONS

Patients with aspirin and NSAID intolerance may develop intolerance to COX-2 inhibitors, especially with repeated exposure.

Medications as asthma triggers

Certain medications can generate asthma symptoms, with the potential to cause considerable morbidity. This article focuses on the common drugs that have the potential to cause distinct respiratory reactions in asthmatics: aspirin and other nonsteroidal anti-inflammatory drugs, beta-blockers, and angiotensin-converting enzyme inhibitors. The means by which these medications can trigger asthma vary in terms of acuity of onset, severity, and the mechanisms involved. The general and most practical approach is avoidance and cautious use of these drugs in asthmatics. However, these classes of medications can exert a major role in the management of common and serious diseases. Fortunately, controller therapy for asthma and alternative or more selective medications for the treatment of these conditions are now available.

Aspirin-induced asthma: clinical aspects, pathogenesis and management

Aspirin (acetylsalicylic acid)-induced asthma (AIA) consists of the clinical triad of asthma, chronic rhinosinusitis with nasal polyps, and precipitation of asthma and rhinitis attacks in response to aspirin and other NSAIDs. The prevalence of the syndrome in the adult asthmatic populations is approximately 4-10%. Respiratory disease in these patients may be aggressive and refractory to treatment. The aetiology of AIA is complex and not fully understood, but most evidence points towards an abnormality of arachidonic acid (AA) metabolism. Cyclo-oxygenase (COX), the rate-limiting enzyme in AA metabolism, exists as two main isoforms. COX-1 is the constitutive enzyme responsible for synthesis of protective prostanoids, whereas COX-2 is induced under inflammatory conditions. A number of theories regarding its pathogenesis have been proposed. The shunting hypothesis proposes that inhibition of COX-1 shunts AA metabolism away from production of protective prostanoids and towards cysteinyl leukotriene (cys-LT) biosynthesis, resulting in bronchoconstriction and increased mucus production. The COX-2 hypothesis proposes that aspirin causes a structural change in COX-2 that results in the generation of products of the lipoxygenase pathway. It is speculated that this may result in the formation of mediators that cause respiratory reactions in AIA. Related studies provide evidence for abnormal regulation of the lipoxygenase pathway, demonstrating elevated levels of cys-LTs in urine, sputum and peripheral blood, before and following aspirin challenge in AIA patients. These studies suggest that cys-LTs are continually and aggressively synthesised before exposure to aspirin and, during aspirin-induced reactions, acceleration of synthesis occurs. A genetic polymorphism of the LTC4S gene has been identified consisting of an A to C transversion 444 nucleotides upstream of the first codon, conferring a relative risk of AIA of 3.89. Furthermore, carriers of the C444 allele demonstrate a dramatic rise in urinary LTE(4) following aspirin provocation, and respond better to the cys-LT antagonist pranlukast than A444 homozygotes.AIA patients have an aggressive form of disease, and treatment should include combination therapy with inhaled corticosteroids, beta(2)-adrenoceptor agonists and LT modifiers. Furthermore, recently developed inhibitors of COX-2 may be safer in patients with AIA.

Safety of high-dose rofecoxib in patients with aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is characterized by progressive sinusitis, nasal polyposis, and asthma that begins and continues in the absence of exposure to aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Cross-sensitivity to all NSAIDs that inhibit cyclooxygenase-1 (COX-1) occurs in these individuals. Reactions to aspirin and NSAIDs in patients with AERD are largely due to inhibition of COX-1. Despite accumulating data on the safety of COX-2 selective inhibitors in AERD, concern still remains that high doses of a COX-2 inhibitor may be sufficient to induce a cross-reaction.

OBJECTIVE

To determine whether high-dose rofecoxib cross-reacts in patients with AERD and asthma.

METHODS

Sixty asthmatic patients underwent blinded placebo-controlled oral challenges with 50 mg of rofecoxib. Aspirin sensitivity was subsequently confirmed in all patients with the use of single-blinded aspirin challenges.

RESULTS

None of the 60 patients experienced any symptoms, changes in nasal examination results, or declines in lung function during rofecoxib challenge. All 60 patients experienced respiratory reactions to aspirin challenge, with a mean provoking dose of 57 mg. The exact 1-sided 95% confidence interval for the underlying probability of 50 mg of rofecoxib inducing respiratory cross-reactions in patients with AERD is 0 to 0.05, or 0% to 5%.

CONCLUSIONS

These results confirm the lack of cross-reactivity of aspirin and the highly selective COX-2 inhibitors in AERD. We suggest that it is time for the labeling of highly selective COX-2 inhibitors to reflect these data and for the warning that patients with AERD in particular and asthmatic patients in general avoid selective COX-2 inhibitors to be removed.

Adverse Reactions to Selective Cyclooxygenase-2 Inhibitors (Coxibs)

Coxibs, selective inhibitors of arachidonic acid cyclooxygenase-2, constitute a new, clinically useful therapeutic class of drugs that possess analgesic, antiinflammatory, and antipyretic properties. The drug inserts of prescription information presently provide a warning contraindicating their use in patients with aspirin-intolerant asthma and aspirin and NSAID hypersensitivity. However, according to investigations reported until now, most of those NSAID-sensitive individuals will tolerate coxibs. Careful oral challenge is useful for patient management since some cutaneous and systemic reactions of hypersensitivity, especially when sulfonamide-containing coxibs are employed, may occur.

Aspirin and NSAID sensitivity

Aspirin and the older nonsteroidal anti-inflammatory drugs (NSAIDs) that block cyclo-oxygenase-1 (COX-1) induce asthma attacks in patients with aspirin-exacerbated respiratory disease and urticaria in patients with chronic idiopathic urticaria. Weak inhibitors of COX-1, such as acetaminophen and salsalate, crossreact also but only with high doses of the drugs. Partial inhibitors of both COX-1 and COX-2, such as nimesulide and meloxicam, also cross-react but only at high drug doses. COX-2 inhibitors do not cross-react; however, all NSAIDs, including the selective COX-2 inhibitors, can sensitize patients and induce urticaria or anaphylaxis on next exposure to the drug.

Uteroglobin represses allergen-induced inflammatory response by blocking PGD2 receptor-mediated functions

Uteroglobin (UG) is an antiinflammatory protein secreted by the epithelial lining of all organs communicating with the external environment. We reported previously that UG-knockout mice manifest exaggerated inflammatory response to allergen, characterized by increased eotaxin and Th2 cytokine gene expression, and eosinophil infiltration in the lungs. In this study, we uncovered that the airway epithelia of these mice also express high levels of cyclooxygenase (COX)-2, a key enzyme for the production of proinflammatory lipid mediators, and the bronchoalveolar lavage fluid (BALF) contain elevated levels of prostaglandin D₂. These effects are abrogated by recombinant UG treatment. Although it has been reported that prostaglandin D₂ mediates allergic inflammation via its receptor, DP, neither the molecular mechanism(s) of DP signaling nor the mechanism by which UG suppresses DP-mediated inflammatory response are clearly understood. Here we report that DP signaling is mediated via p38 mitogen–activated protein kinase, p44/42 mitogen–activated protein kinase, and protein kinase C pathways in a cell type–specific manner leading to nuclear factor–κB activation stimulating COX-2 gene expression. Further, we found that recombinant UG blocks DP-mediated nuclear factor–κB activation and suppresses COX-2 gene expression. We propose that UG is an essential component of a novel innate homeostatic mechanism in the mammalian airways to repress allergen-induced inflammatory responses.

Safety of COX-2 inhibitors in asthma patients with aspirin hypersensitivity

OBJECTIVE

To review the safety of cyclooxygenase-2 (COX-2) inhibitors in asthma patients with aspirin hypersensitivity.

DATA SOURCES

Clinical studies were identified using MEDLINE (1966-September 2002). Key search terms included cyclooxygenase inhibitors, aspirin, asthma, and hypersensitivity. English-language articles were identified and included. References from the identified articles were also reviewed.

DATA SYNTHESIS

The literature provides information regarding the safety of COX-2 inhibitors in asthma patients with aspirin-exacerbated respiratory disease (AERD). The mechanism of AERD involves inhibition of cyclooxygenase, particularly COX-1. Inhibition of COX-1 causes an increased production of certain inflammatory mediators, which results in the reactions seen with AERD. Considering this mechanism, COX-2 inhibitors may be an alternative to aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) in a patient with AERD. This article analyzes 4 studies to evaluate the safety of COX-2 inhibitors in this population.

RESULTS

The 4 studies evaluated included a total of 172 patients with AERD. All patients included demonstrated intolerance to aspirin or NSAIDs and tolerated the selective COX-2 inhibitor administered.

CONCLUSIONS

COX-2 inhibitors provide a potentially safe alternative for treatment of inflammatory conditions in patients with AERD.

Tolerability of rofecoxib in patients with adverse reactions to nonsteroidal anti-inflammatory drugs: a study of 216 patients and literature review

BACKGROUND

Adverse reactions to nonsteroidal anti-inflammatory drugs (NSAIDs) are frequent, particularly among patients with chronic urticaria or asthma. The identification of an alternative safe and reliable drug is a common problem in clinical practice.

OBJECTIVE

To assess the tolerability of rofecoxib, a new NSAID that selectively inhibits the inducible isoform of cyclooxygenase, in a large group of NSAID-sensitive patients.

METHODS

We studied 216 patients (164 females and 52 males) who had suffered adverse reactions to one or more NSAIDs; 98 subjects (45.4%) had experienced reactions to only one NSAID (single hypersensitivity) and 118 subjects (54.6%) had reacted to multiple NSAIDs (multiple hypersensitivity). Cutaneous reactions were reported by 79.6% of the subjects, respiratory symptoms by 10.7%, cutaneous and respiratory symptoms by 8.3%, anaphylaxis by 1.4%. All the subjects underwent a single-blind, placebo-controlled oral challenge with divided therapeutic doses of rofecoxib (6.25 mg +18.75 mg 1 h later = cumulative dose of 25 mg).

RESULTS

No reactions to the placebo were observed; only 1 subject (0.46%) experienced an urticarial reaction, after the second dose of rofecoxib.

CONCLUSIONS

Considering previous studies and our own data, rofecoxib was well tolerated by all of the 174 patients with exclusively NSAID-related respiratory symptoms. Rofecoxib also had a very low rate (1.6%) of cross-reactivity in the 600 patients with exclusively cutaneous reactions to NSAIDs.

Cyclooxygenase enzymes in allergic inflammation and asthma

The cyclooxygenase enzyme system produces eicosanoids which mediate many important physiological and pathological functions. Experimental and clinical data suggest a role for this enzyme system in the pathogenesis of allergic inflammation and asthma. This article focuses on the function of this pathway in the lung, reviews evidence implicating the involvement of this pathway in asthma and allergic airway inflammation, and discusses implications for the treatment of asthmatics with cyclooxygenase inhibitors.

Rofecoxib: an update on physicochemical, pharmaceutical, pharmacodynamic and pharmacokinetic aspects

Rofecoxib (MK-966) is a new generation non-steroidal anti-inflammatory agent (NSAID) that exhibits promising anti-inflammatory, analgesic and antipyretic activity. It selectively inhibits cyclooxygenase (COX)-2 isoenzyme in a dose-dependent manner in man. No significant inhibition of COX-1 is observed with rofecoxib up to doses of 1000 mg. The pharmacokinetics of rofecoxib has been found to be complex and variable. Mean oral bioavailability after single dose of rofecoxib (12.5, 25 or 50 mg) is 93% with t(max) varying widely between 2 and 9 h. It is highly plasma-protein bound and is metabolized primarily by cytosolic reductases to inactive metabolites. Rofecoxib is eliminated predominantly by hepatic metabolism with a terminal half-life of approximately 17 h during steady state. Various experimental models and clinical studies have demonstrated rofecoxib to be superior, or at least equivalent, in anti-inflammatory, analgesic and antipyretic efficacy to comparator nonselective NSAIDs in osteoarthritis, rheumatoid arthritis and other pain models. Emerging evidence suggests that rofecoxib may also find potential use as supportive therapy in various pathophysiologic conditions like Alzheimer's disease, and in various malignant tumours and polyps, where COX-2 is overly expressed. Rofecoxib is generally well-tolerated. Analysis of data pooled from several trials suggests that rofecoxib is associated with fewer incidences of clinically symptomatic gastrointestinal ulcers and ulcer complications vis-à-vis conventional NSAIDs. However, this gastropreserving effect may be negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Rofecoxib tends to show similar tolerability for renal and cardiothrombotic events as compared with nonnaproxen nonselective NSAIDs. No clinically significant drug interaction has been reported for rofecoxib except with diuretics, where it reverses their salt-wasting effect and thus can be clinically exploited in electrolyte-wasting disorders. There is only modest information about the physicochemical and pharmaceutical aspects of rofecoxib. Being poorly water soluble, its drug delivery has been improved using varied formulation approaches. Although it is stable in solid state, rofecoxib is photosensitive and base-sensitive in solution form with its degradation mechanistics elucidated. Analytical determinations of rofecoxib and its metabolites in biological fluids employing HPLC with varied types of detectors have been reported. Isolated studies have also been published on the chromatographic and spectrophotometric assay of rofecoxib and its degradants in bulk samples and pharmaceutical dosage forms. The current article provides an updated overview on the physicochemical, pharmaceutical, pharmacokinetic and pharmacodynamic vistas of rofecoxib.