Do some inhibitors of COX-2 increase the risk of thromboembolic events?: Linking pharmacology with pharmacoepidemiology

[The problem of cardiac safety of nonsteroidal anti-inflammatory drugs]

The paper considers an update on the mechanisms for the development of adverse reactions of nonsteroidal anti-inflammatory drugs on the cardiovascular system.

Non-steroidal anti-inflammatory drugs and risk of cerebrovascular events in patients with osteoarthritis: a nested case-control study

Recent studies show that the risk of cardiovascular adverse events for certain traditional non-steroidal anti-inflammatory drugs (NSAIDs) is similar to that of rofecoxib. While these results are focused on ischemic cardiomyopathy, there is little evidence concerning the risk of ischemic stroke/transient ischemic attack and hemorrhagic stroke. Additionally, there is no information on nimesulide and ketoprofen, the most frequently prescribed NSAIDs in Italy, along with diclofenac. This study aims to determine whether the use of NSAIDs is associated with an increased risk of cerebrovascular events in Italy. We performed a case-control analysis nested in a cohort of patients with osteoarthritis between 2002 and 2011 who were newly treated with NSAIDs. The patients were followed until December 31, 2012. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (95% CI) of cerebrovascular events (index date) associated with current (until 30 days before the index date), recent (31-365 days) and past (>365 days) use of NSAIDs. Within a cohort of 29,722 patients, 1566 cases (1546 matched with controls) were identified (incidence rate = 11.0/1000 person-years). The overall rate of cerebrovascular event was not elevated with current NSAIDs overall when compared with past use. Among individual NSAIDs, diclofenac and ketoprofen were the molecules significantly associated with an increased rate of cerebrovascular events (OR = 1.53; 95% CI 1.04-2.24; OR = 1.62; 95% CI 1.02-2.58, respectively). The most frequent event was hemorrhagic stroke following the use of ketoprofen (OR = 2.09; 95% CI 1.05-4.15). Diclofenac and ketoprofen seemed to increase the risk of cerebrovascular events. These findings might influence the choice of NSAIDs according to patient characteristics.

Cyclooxygenase-1 and -2: molecular targets for cervical neoplasia

Cyclooxygenase (COX) is a key enzyme responsible for inflammation, converting arachidonic acid to prostaglandin and thromboxane. COX has at least two isoforms, COX-1 and COX-2. While COX-1 is constitutively expressed in most tissues for maintaining physiologic homeostasis, COX-2 is induced by inflammatory stimuli including cytokines and growth factors. Many studies have shown that COX-2 contributes to cancer development and progression in various types of malignancy including cervical cancer. Human papillomavirus, a necessary cause of cervical cancer, induces COX-2 expression via E5, E6 and E7 oncoproteins, which leads to prostaglandin E2 increase and the loss of E-cadherin, promotes cell proliferation and production of vascular endothelial growth factor. It is strongly suggested that COX-2 is associated with cancer development and progression such as lymph node metastasis. Many studies have suggested that non-selective COX-2 inhibitors such as non-steroidal anti-inflammatory drugs (NSAIDs), and selective COX-2 inhibitors might show anti-cancer activity in COX-2 -dependent and -independent manners. Two phase II trials for patients with locally advanced cervical cancer showed that celecoxib increased toxicities associated with radiotherapy. Contrary to these discouraging results, two phase II clinical trials, using rofecoxib and celecoxib, demonstrated the promising chemopreventive effect for patients with cervical intraepithelial neoplasia 2 or 3. However, these agents cause a rare, but serious, cardiovascular complication in spite of gastrointestinal protection in comparison with NSAIDs. Recent pharmacogenomic studies have showed that the new strategy for overcoming the limitation in clinical application of COX-2 inhibitors shed light on the use of them as a chemopreventive method.

A randomized controlled trial of celecoxib to prevent recurrence of nonmuscle-invasive bladder cancer

Significant morbidity and expense result from frequent recurrences of nonmuscle-invasive bladder cancer (NMIBC) after standard treatment, and carcinoma in situ (Tis) is a poor prognostic factor. Predicated on observational and preclinical data strongly supporting cyclooxygenase-2 (COX-2) in the pathogenesis, and the activity of COX-2 inhibitors, in bladder cancer, we conducted a randomized, double-blind, placebo-controlled trial to determine whether celecoxib could reduce the time-to-recurrence (TTR) in NMIBC patients at high risk for recurrence. A total of 146 patients were randomized to celecoxib (200 mg) or placebo orally twice daily for at least 12 months. The average treatment duration was 1.25 years. Primary intent-to-treat analysis revealed celecoxib did not statistically significantly prolong TTR compared with placebo (P = 0.17, log rank) with a median follow-up of 2.49 years. The recurrence-free rate at 12 months with celecoxib was 88% (95% CI: 0.81-0.96) versus 78% (95% CI: 0.69-0.89) with placebo. After controlling for covariates with Cox regression analysis, recurrence rates did not differ between the two study arms (HR = 0.69; 95% CI: 0.37-1.29). However, celecoxib had a marginally significant effect on reducing metachronous recurrences (vs. placebo) with HR of 0.56 (95% CI: 0.3-1.06; P = 0.075). Celecoxib was well tolerated, with similar adverse events and quality-of-life in both arms. Our clinical trial results do not show a clinical benefit for celecoxib in preventing NMIBC recurrence but further investigation of COX-2 inhibitors in this setting is warranted.

Adverse drug reactions associated with the use of NSAIDs: a case/noncase analysis of spontaneous reports from the French pharmacovigilance database 2002-2006

To evaluate the safety profile of eight oral nonsteroidal anti-inflammatory drugs (NSAIDs) available in France, using data reported through the French pharmacovigilance system. Data (from 2002 to 2006) were analysed for aceclofenac, diclofenac, ketoprofen, meloxicam, naproxen, nimesulide, piroxicam and tenoxicam, focusing on the reported rates of serious adverse drug reactions (ADRs) in the following system organ classes: gastrointestinal, hepatic, cutaneous, renal and cardiovascular. A total of 42 389 serious ADR reports were identified, and 38 506 were included in a case/noncase analysis. Ketoprofen was associated with the highest cumulative reported rate of serious ADRs (0.78 cases per million defined daily doses), followed by diclofenac (0.58), nimesulide (0.52), naproxen (0.50), piroxicam (0.47), tenoxicam (0.42), meloxicam (0.41) and aceclofenac (0.30). The most frequently reported serious ADRs were cutaneous, followed by gastrointestinal, hepatic, renal and rarely, cardiovascular events. In the case/noncase analysis, ketoprofen, piroxicam and naproxen were associated with the highest risk of serious gastrointestinal ADRs (odds ratios [ORs] of 6.87, 6.54 and 5.07, respectively). Nimesulide and aceclofenac were associated with the highest risk of liver ADRs (adjusted ORs of 4.53 and 3.67, respectively), as was meloxicam for cutaneous ADRs (adjusted OR of 3.15) and tenoxicam for renal ADRs (adjusted OR of 3.17). The most frequent serious ADRs reported with the selected oral NSAIDs are cutaneous, followed by gastrointestinal, hepatic and renal events. The highest risks for serious gastrointestinal, hepatic, cutaneous and renal adverse events were linked, respectively, with ketoprofen, nimesulide, meloxicam and tenoxicam compared with the other NSAIDs.

Pharmacogenomic technologies: a necessary "luxury" for better global public health?

BACKGROUND

Pharmacogenomic technologies aim to redirect drug development to increase safety and efficacy of individual care. There is much hope that their implementation in the drug development process will help respond to population health needs, particularly in developing countries. However, there is also fear that novel pharmacogenomic drugs will remain too costly, be designed for the needs of the wealthy nations, and so constitute an unnecessary "luxury" for most populations. In this paper, we analyse the promise that pharmacogenomic technologies hold for improving global public health and identify strategies and challenges associated with their implementation.

DISCUSSION

This paper evaluates the capacity of pharmacogenomic technologies to meet six criteria described by the University of Toronto Joint Centre for Bioethics group: 1) impact of the technology, 2) technology appropriateness, 3) capacity to address local burdens, 4) feasibility to be implemented in reasonable time, 5) capacity to reduce the knowledge gap, and 6) capacity for indirect benefits. We argue that the implementation of pharmacogenomic technologies in the drug development process can positively impact population health. However, this positive impact depends on how and for which purposes the technologies are used. We discuss the potential of these technologies to stimulate drug discovery in the case of rare (orphan diseases) or neglected diseases, but also to reduce acute adverse drug reactions in infectious disease treatment and prevention, which promises to improve global public health.

CONCLUSIONS

The implementation of pharmacogenomic technologies may lead to the development of drugs that appear to be a "luxury" for populations in need of numerous interventions that are known to have a demonstrable impact on population health (e.g., secure access to potable water, reduction of social inequities, health education). However, our analysis shows that pharmacogenomic technologies do have the potential to redirect drug development and distribution so as to improve the health of vulnerable populations. Strategies should thus be developed to better direct their implementation towards meeting the needs and responding to the realities of populations of the developing world (i.e., social, cultural and political acceptability, and local health burdens), making pharmacogenomic technologies a necessary "luxury" for global public health.

Postmarketing surveillance of serious adverse events associated with the use of rofecoxib from 1999-2002

OBJECTIVE

The authors performed a postmarketing database analysis to evaluate the incidence of cardiovascular and other serious adverse events (SAEs) reported to the US Food and Drug Administration's Adverse Event Reporting System (AERS) involving the use of rofecoxib.

RESEARCH DESIGN AND METHODS

The authors studied all adverse events involving rofecoxib reported to the AERS from inception of the drug until 2002. An emphasis was placed on cardiovascular and other SAEs of interest categorized using the high level group terms hemorrhage, edema, thrombosis, embolism, and death.

RESULTS

There were 31,024 reports of SAEs associated with the use of rofecoxib, which was considered primary suspect in 97.8% of these reports. There were 3915, 3677, 1653, 1917, and 233 reports of hemorrhage, edema, death, thrombosis, and embolism, respectively. Relative to the overall population in this dataset, reports of hemorrhage, death, thrombosis, and embolism consisted of a greater proportion of males. The mean age for patients that reported hemorrhage, death, and thrombosis was older, whereas the mean age for embolism and edema was younger than the overall population in this dataset. Aspirin was the most commonly reported concomitant medication (7.4% of reports) followed by acetaminophen (5.4%). Reports containing concomitant use of anti-coagulants, Cox-1, and nonselective inhibitors (each p < 0.001) but not Cox-2 inhibitors were associated with increased age while only anti-coagulants and Cox-1 inhibitors (each p < 0.001) were associated with more males. Reports containing concomitant use of an anti-coagulant or an NSAID accounted for a disproportionate incidence of hemorrhage, edema, embolism, and death. Most notably, the odds of a hemorrhagic event for those reporting concomitant use of an anti-coagulant, Cox-1, non-selective, or Cox-2 inhibitor was 3.05 (p < 0.001), 3.07 (p < 0.001), 2.07 (p < 0.001), and 1.18 (p < 0.001), respectively. Some weaknesses of this type of analysis are the retrospective nature of such a study, the inability to find causality, and that the data can contains multiple reports from any one individual.

CONCLUSIONS

It can be postulated that in addition to the risk of heart attack and stroke, rofecoxib users were at increased risk of hemorrhage, in addition to other thrombotic and embolic adverse events, which was exacerbated in those taking blood thinners or NSAIDs.

Proteomics-based approach to elucidate the mechanism of antitumor effect of curcumin in cervical cancer

Cervical cancer is the second leading cause of cancer death for women in the world. A potential target for preventing and treating cervical cancer is cyclooxygenase-2 (cox-2). Curcumin is an anti-inflammatory agent that is known to have anti-cox-2 activity. In this study we examined the expression of cox-2 in cervical cancer and its precursors by immunohistochemistry. The effect of curcumin in inhibiting cervical cancer cells was determined via 2-dimensional gel electrophoresis, data analysis, and ingenuity pathway analysis. No significant differences in the expression of cox-2 in squamous cell carcinoma, and carcinoma in situ were observed. However, there was a statistically significant difference in the expression of cox-2 in adenocarcinoma in comparison to normal (p value=0.01) and squamous cell carcinoma (p value=0.02) tissues. Proteins associated with cancer and cell cycle were significantly altered in cultured cells. Curcumin may have antitumor effect in cervical cancer.

The cycloxygenase 2 (COX-2) story: it's time to explain, not inflame

Despite initial promising reports that anti-inflammatory properties of cycloxygenase-2 (COX-2) inhibitors may confer anti-atherosclerosis effects and stabilize the atherosclerotic plaque, subsequent data from long-term clinical trials have shown that selective COX-2 inhibitors are associated with increased risk of cardiovascular events. The commonly cited explanation is that selective inhibition of COX-2 leads to depletion of prostacyclin, whereas the production of pro-thrombotic thromboxane by means of cycloxygenase-1 (COX-1) is unopposed. This hypothesis seems unlikely as the overall explanation, because low-dose aspirin does not decrease the increased risk associated with COX-2 inhibitors. Moreover, the risk associated with nonselective COX inhibitors may be similar to selective COX-2 inhibitors. Alternative hypotheses include (1) elevated blood pressure, (2) abnormal vascular remodeling, (3) inhibition of protective mechanisms against ischemia-reperfusion injury, and (4) inhibition of 15-epi-lipoxin production. Varying results in different experimental models may be related to the fact that COX-2 is involved in numerous cellular functions. Inhibiting COX-2 in inflammatory cells may have favorable effects, whereas in organs such as the heart and brain and/or blood vessels may have deleterious effects. Currently, the "selective COX-2 inhibitors" are not selective in the sense that they inhibit COX-2 in all tissues without predilection to inflammatory cells and, as a result, may summate to increase the risk of cardiovascular events.

The effect of 1-furan-2-yl-3-pyridine-2-yl-propenone on pharmacokinetic parameters of warfarin

1-Furan-2-yl-3-pyridine-2-yl-propenone (FPP-3) is an investigatory drug which has a dual inhibitory action on cyclooxygenase (COX) and 5-lipoxygenase (5-LOX). We examined its effect on the pharmacokinetics of warfarin. Three consecutive days of pretreatment with 17 mg/kg of FPP-3 had no significant effect on the pharmacokinetic parameters of warfarin when orally administered to rats. A higher dosage of FPP-3 however, did cause significant changes in the pharmacokinetic parameters of wafarin. The cytochrome P450 activity test demonstrated that the metabolism of R-warfarin was significantly inhibited by FPP-3 while there was little or no inhibition of the metabolism of S-warfarin, which is mainly responsible for its anticoagulant effect. Therefore, it appears that the alteration in the pharmacokinetic parameters of warfarin was due to the inhibitory effect of FPP-3 on the metabolism of R-warfarin. Although there was a significant increase in the plasma concentration, the area under the curve, half life of warfarin, and prothrombin time were not significantly changed. Based on these findings, the pharmacokinetic drug interaction between FPP-3 and warfarin mainly involves R-warfarin and, therefore, this interaction may not be of clinical significance in terms of warfarin-related toxicity.

Perioperative pain management

The under-treatment of postoperative pain has been recognised to delay patient recovery and discharge from hospital. Despite recognition of the importance of effective pain control, up to 70% of patients still complain of moderate to severe pain postoperatively. The mechanistic approach to pain management, based on current understanding of the peripheral and central mechanisms involved in nociceptive transmission, provides newer options for clinicians to manage pain effectively. In this article we review the rationale for a multimodal approach with combinations of analgesics from different classes and different sites of analgesic administration. The pharmacological options of commonly used analgesics, such as opioids, NSAIDs, paracetamol, tramadol and other non-opioid analgesics, and their combinations is discussed. These analgesics have been shown to provide effective pain relief and their combinations demonstrate a reduction in opioid consumption. The basis for using non-opioid analgesic adjuvants is to reduce opioid consumption and consequently alleviate opioid-related adverse effects. We review the evidence on the opioid-sparing effect of ketamine, clonidine, gabapentin and other novel analgesics in perioperative pain management. Most available data support the addition of these adjuvants to routine analgesic techniques to reduce the need for opioids and improve quality of analgesia by their synergistic effect. Local anaesthetic infiltration, epidural and other regional techniques are also used successfully to enhance perioperative analgesia after a variety of surgical procedures. The use of continuous perineural techniques that offer prolonged analgesia with local anaesthetic infusion has been extended to the care of patients beyond hospital discharge. The use of nonpharmacological options such as acupuncture, relaxation, music therapy, hypnosis and transcutaneous nerve stimulation as adjuvants to conventional analgesia should be considered and incorporated to achieve an effective and successful perioperative pain management regimen.

COX-2 inhibitors and the heart: are all coxibs the same?

The selective COX-2 inhibitors (coxibs) were originally developed to minimise the adverse effects of conventional non-steroidal anti-inflammatory drugs (NSAIDs) while maintaining the same analgesic and anti-inflammatory properties. Many large studies confirmed the improved gastric side effect profile of coxibs compared with non-selective NSAIDs; however, reports of increased cardiovascular morbidity and mortality followed, and the manufacturer Merck was forced to withdraw rofecoxib (Vioxx) from the market. Other coxibs have also either perished or had restrictions placed on their use. However, there seem to be significant differences between coxibs regarding their cardiovascular profiles, and the evidence for a class effect is dubious. In this paper, the current body of knowledge regarding the cardiovascular toxicities of coxibs is reviewed. The take home message for prescribing NSAIDs and those coxibs still on the market seems to be one of caution rather than contraindication, except in patients with significant cardiovascular risk factors.

Linking pharmacovigilance with pharmacogenetics

The ability to identify individuals who are susceptible to adverse drug reactions (ADRs) has the potential to reduce the personal and population costs of drug-related morbidity. Some individuals may show an increased susceptibility to certain ADRs through genetic polymorphisms that alter their responses to various drugs. We wished to establish a methodology that would be acceptable to members of the general population and that would enable estimation of the risks that specific genetic factors confer on susceptibility to specific ADRs. Buccal swabs were selected as a minimally invasive method to obtain cells for DNA extraction. We wished to determine whether DNA of sufficient quantity and quality could be obtained to enable genotyping for two different polymorphic genes that code for enzymes that are widely involved in drug disposition. This article describes a small pilot study of methodology developed in the New Zealand Intensive Medicines Monitoring Programme (IMMP) to link prescription event monitoring (PEM) studies with pharmacogenetics. The methodology involves a nested case-control study design to investigate whether patients with genetic variants in P-glycoprotein (P-gp) and cytochrome P450 (CYP) 2C9 are more susceptible to psychiatric or visual disturbances following cyclo- oxygenase-2 inhibitor use (ADR signals identified in the IMMP database) than matched control patients taking the medication without experiencing any ADRs. It was concluded that the use of buccal swabs is acceptable to patients and provides DNA of sufficient quantity and quality for genotyping. Although no differences in the distribution of genotypes in the case and control populations were found in this small study, case-control studies investigating genetic risks for ADRs using drug cohorts from PEM studies are possible, and there are several areas where population-based studies of genetic risk factors for ADRs are needed. Examples are discussed where research in large populations is required urgently. These are: (i) genetic variations affecting P-gp function; (ii) variations affecting drugs metabolised by CYP2C9 and other polymorphic CYP enzymes; (iii) genetic variation in beta-adrenergic receptors and adverse outcomes from beta-adrenoceptor agonist therapy; and (iv) genetic variation in cardiac cell membrane potassium channels and their association with long QT syndromes and serious cardiac dysrhythmias. Such studies will help to identify factors that increase the risk of unwanted outcomes from drug therapy. They will also help to establish in what circumstances genotyping should be performed prior to commencing drug treatment and in tailoring drug treatment for individual patients.

Cyclooxygenase inhibitors in urinary bladder cancer:in vitroandin vivoeffects

More than 14,000 people die from invasive transitional cell carcinoma (TCC) of the urinary bladder yearly in the United States. Cyclooxygenase (COX)-inhibiting drugs are emerging as potential antitumor agents in TCC. The optimal in vitro or in vivo systems to investigate COX inhibitor antitumor effects have not been defined. The purpose of this study was to determine COX-1 and COX-2 expression and antitumor effects of COX inhibitors in human TCC cell lines (HT1376, RT4, and UMUC3 cells) and xenografts derived from those cell lines. COX-2 expression (Western blot, immunocytochemistry) was high in HT1376, modest in RT4, and absent in UMUC3 cells in vitro. Similarly, COX-2 expression was noted in RT4 but not UMUC3 xenografts. COX-2 expression in HT1376 xenografts was slightly lower than that observed in vitro. None of four COX inhibitors evaluated (celecoxib, piroxicam, valeryl salicylate, and NS398) reduced TCC growth in standard in vitro proliferation assays at concentrations that could be safely achieved in vivo (< or =5 micromol/L). Higher celecoxib concentrations (> or =50 micromol/L) inhibited proliferation and induced apoptosis in all three cell lines. Celecoxib or piroxicam treatment in athymic mice significantly delayed progression of HT1376 xenografts, which express COX-2, but not UMUC3 xenografts that lack COX-2 expression. In conclusion, standard in vitro assays were not useful in predicting COX inhibitor antitumor effects observed in vivo. Athymic mice bearing TCC xenografts provide a useful in vivo system for COX inhibitor studies. Results of this study provide justification for further evaluation of COX inhibitors as antitumor agents against TCC.

Diet and rheumatoid arthritis: a review of the literature

INTRODUCTION

Rheumatoid arthritis is a common inflammatory condition. A large number of patients seek alternative or complementary therapies of which diet is an important component. This article reviews the evidence for diet in rheumatoid arthritis along with the associated concept of oral tolerization.

METHODS

References were taken from Medline from 1966 to September 2004. The keywords, rheumatoid arthritis, diet, n-3 fatty acids, vitamins, and oral tolerization, were used.

RESULTS

Randomized controlled trials (RCTs) indicate that dietary supplementation with n-3 fatty acids provides modest symptomatic benefit in groups of patients with rheumatoid arthritis. Epidemiological studies and RCTs show cardiovascular benefits in the broader population and patients with ischemic heart disease. A number of mechanisms through which n-3 fats may reduce inflammation have been identified. In a small number of patients with rheumatoid arthritis, other dietary manipulation such as fasting, vegan, and elimination diets may have some benefit. However, many of these diets are impractical or difficult to sustain long term.

CONCLUSIONS

Dietary manipulation provides a means by which patients can a regain a sense of control over their disease. Dietary n-3 supplementation is practical and can be easily achieved with encapsulated or, less expensively, bottled fish oil.

Temporal Relationship between Use of NSAIDs, Including Selective COX-2 Inhibitors, and Cardiovascular Risk

BACKGROUND AND OBJECTIVE

The search for NSAIDs with less gastrointestinal toxicity led to the introduction of the selective cyclo-oxygenase-2 (COX-2) inhibitors. However, following their introduction into the market, concerns have developed regarding their safety, particularly their cardiovascular safety. The purpose of this study was to assess the cardiovascular risk (events included were myocardial infarction, stroke and myocardial infarction-related deaths) associated with long-term (>180 days of exposure) and short-term (<or=180 days of exposure) use of non-selective NSAIDs, including 'preferential COX-2 inhibitors' (i.e. etodolac, nabumetone and salsalate), and selective COX-2 inhibitors.

METHODS

A retrospective analysis of the Veterans Integrated Service Network 17 Veterans Affairs (VA) database was conducted. Medicare data and Texas Department of Health mortality data were incorporated to capture events occurring outside the VA healthcare network. Patients >or=35 years of age who received celecoxib, rofecoxib, ibuprofen, etodolac and naproxen from 1 January 1999 through 31 December 2001, were included. Multivariate Cox proportional hazard models were used to analyse the relationship between cardiovascular risk and NSAID use, including selective COX-2 inhibitor use, while adjusting for various risk factors.

RESULTS

We identified 12 188 exposure periods (11 930 persons) and 146 cardiovascular events over the entire study period. Compared with long-term ibuprofen use, long-term use of celecoxib (adjusted hazard ratio [HR] 3.64; 95% CI 1.36, 9.70) and rofecoxib (adjusted HR 6.64; 95% CI 2.17, 20.28) was associated with a significant increase in cardiovascular risk. When restricted to patients >or=65 years of age, the cardiovascular risks associated with long-term celecoxib (adjusted HR 7.36; 95% CI 1.62, 33.48) and rofecoxib (adjusted HR 13.24; 95% CI 2.59, 67.68) use increased. Short-term use of celecoxib (adjusted HR 0.75; 95% CI 0.42, 1.35) and rofecoxib (adjusted HR 0.85; 95% CI 0.39, 1.86) was not associated with any significant change in cardiovascular risk when compared with short-term ibuprofen use. Neither long- nor short-term exposure to naproxen and etodolac was associated with cardionegative or cardioprotective effects when compared with ibuprofen use.

CONCLUSIONS

The findings of this observational study, along with recent clinical trial results, suggest that prolonged exposure to selective COX-2 inhibitors may be associated with an increased risk of adverse cardiovascular outcomes.

Drugs for pain management in dentistry

Pain is one of the most common reasons patients seek dental treatment. It may be due to many different diseases/conditions or it may occur after treatment. Dentists must be able to diagnose the source of pain and have strategies for its management. The '3-D's' principle--diagnosis, dental treatment and drugs--should be used to manage pain. The first, and most important, step is to diagnose the condition causing the pain and identify what caused that condition. Appropriate dental treatment should then be undertaken to remove the cause of the condition as this usually provides rapid resolution of the symptoms. Drugs should only be used as an adjunct to the dental treatment. Most painful problems that require analgesics will be due to inflammation. Pain management drugs include non-narcotic analgesics (e.g., non-steroidal anti-inflammatory drugs, paracetamol, etc) or opioids (i.e., narcotics). Non-steroidal anti-inflammatory drugs (NSAIDs) provide excellent pain relief due to their anti-inflammatory and analgesic action. The most common NSAIDs are aspirin and ibuprofen. Paracetamol gives very effective analgesia but has little anti-inflammatory action. The opioids are powerful analgesics but have significant side effects and therefore they should be reserved for severe pain only. The most commonly-used opioid is codeine, usually in combination with paracetamol. Corticosteroids can also be used for managing inflammation but their use in dentistry is limited to a few very specific situations.

A comparison of reported gastrointestinal and thromboembolic events between rofecoxib and celecoxib using observational data

BACKGROUND AND OBJECTIVES

Rofecoxib, a selective cyclo-oxygenase (COX)-2 inhibitor, was a widely marketed drug that was used for relief of pain and inflammation in arthritic conditions. It was withdrawn from the market worldwide in September 2004 because of an increased risk of cardiovascular events. Celecoxib, which belongs to the same class of drugs, is now under scrutiny for the risk of similar events. The objective of our study was to compare the incidence of gastrointestinal (GI) [symptomatic and complicated upper GI] events and thromboembolic (cardiovascular, cerebrovascular and peripheral venous) events reported for patients prescribed rofecoxib or celecoxib in primary care.

METHODS

A retrospective analysis of selected events was conducted using data collected from previously conducted prescription-event monitoring (PEM) studies for rofecoxib and celecoxib. PEM is an observational cohort technique. Exposure data were derived from dispensed prescriptions for rofecoxib (July-November 1999) and celecoxib (May-December 2000) that were written by primary care general practitioners in England. Outcome data were clinical events and information on potential risk factors reported on simple questionnaires (posted to prescribers approximately 9 months after the date of the first prescription). Incidence rates of the first event during treatment within each thromboembolic and GI group were calculated during the 270 days after the patient started receiving either of the drugs; crude and adjusted rate ratios (RR) were calculated for rofecoxib compared with celecoxib using Poisson regression modelling.

RESULTS

The rofecoxib and celecoxib PEM cohorts contained 15 268 and 17 458 patients, respectively. For the GI event groups, the adjusted RRs for rofecoxib compared with celecoxib were: 1.21 (95% CI 1.09, 1.36) for symptomatic upper GI events and 1.60 (95% CI 0.95, 2.70) for complicated upper GI conditions. For the thromboembolic event groups, the adjusted RRs were: 1.04 (95% CI 0.50, 2.17) for cardiovascular thromboembolic events; 1.43 (95% CI 0.86, 2.38) for cerebrovascular thromboembolic events; and 0.36 (95% CI 0.01, 1.34) for peripheral venous thromboembolic events.

CONCLUSIONS

This study was a retrospective comparison of PEM studies conducted for rofecoxib and celecoxib. For symptomatic upper GI events, a 21% increase in the relative rate was found for rofecoxib users compared with celecoxib users after adjusting for identified risk factors. For complicated upper GI events, no statistically significant difference in the incidence was observed between rofecoxib and celecoxib users after adjusting for identified risk factors. For the three thromboembolic event groups, no evidence of a statistically significant difference between rofecoxib and celecoxib users was found after adjusting for identified risk factors. This study contributes to the understanding of the association between COX-2 inhibitors and thromboembolic events. However, it should be borne in mind that we had information on only a limited number of confounding variables for thromboembolic events. Further research is required to fully understand the risks and benefits of using celecoxib and other COX-2 inhibitors. Meanwhile, doctors should be cautious when prescribing these products, particularly to patients with risk factors for developing thromboembolic events.

Inhibition of cytokine-induced prostanoid biogenesis by phytochemicals in human colonic fibroblasts

Many of the inflammatory pathways regulating the production of prostanoids are implicated in the development of colon cancer. Diets rich in fruits and vegetables are associated with decreased rates of colon cancer and this may reflect anti-inflammatory properties of some phytochemicals in plant-based foods. In order to ascertain which of the many dietary compounds may be protective, a cell-based screening method was established to determine their effects on the production of prostanoids. By up-regulating prostaglandin H synthase-2 in human colonic fibroblast cells with cytokines, we have investigated the potential protective effect of a structurally related group of phytochemicals on prostanoid biogenesis. Several of the compounds significantly inhibited prostanoid biogenesis, by up to 81% and others enhanced prostanoid production. All of the compounds that enhanced prostanoid production belonged to the hydroxylated benzoic acid family and good correlation was observed with their redox activity and the ability to enhance prostanoid production. Common structural features of the inhibitors were the presence of 4-hydroxyl and 3-methoxyl substituents on the aromatic ring and/or the presence of a three-carbon side-chain on C1.

Cyclo-oxygenase-2 inhibitors: when should they be used in the elderly?

Chronic pain in the elderly is frequently a result of arthritic disorders, particularly osteoarthritis. The cyclo-oxygenase (COX)-2 inhibitors are as effective as standard NSAIDs for the relief of pain and for improving function in elderly patients with osteoarthritis and rheumatoid arthritis. COX-2 inhibitors increase the risk of serious gastroduodenal adverse reactions but there is evidence that they carry a lower risk for these adverse effects than standard NSAIDs, except when there is concurrent aspirin use. Since gastroduodenal disorders are the most frequently reported serious adverse effects of NSAIDs and these disorders occur more frequently in the elderly, COX-2 inhibitors offer an alternative to standard NSAIDs in this age group. However, they are not appropriate for many patients with cardiovascular and renal disease. The adverse reaction profile of the COX-2 inhibitors has confirmed the role of the COX-2 enzyme in renal function, salt and water homeostasis and the vascular endothelium. Thus, like standard NSAIDs, COX-2 inhibitors can cause renal failure, hypertension and exacerbation of cardiac failure. Of note is that these disorders are dose related. Thus, there are good reasons to avoid high doses of COX-2 inhibitors in the elderly. Clinical trials indicate that daily doses of rofecoxib 12.5 mg, celecoxib 100-200 mg, valdecoxib 10mg and etoricoxib 60 mg are the minimum effective doses of these agents. Data from the New Zealand Intensive Medicines Monitoring Programme indicate that celecoxib 200 mg/day and rofecoxib 25 mg/day are/were the most commonly prescribed doses and that 6% of patients had taken rofecoxib 50 mg/day for longer than recommended. Recent research indicates that COX-2 inhibitors have a thrombotic potential, especially in high doses and when use is prolonged, and this further limits the extent to which they can be used in the elderly. Important interactions with COX-2 inhibitors in the elderly include those with warfarin, which can result in loss of control of anticoagulation, and those with ACE inhibitors, angiotensin II type 1 receptor antagonists and diuretics, which can result in loss of control of blood pressure and cardiac failure and, in hypovolaemic conditions, renal failure. The clinical significance of an interaction between celecoxib and aspirin to reduce the antiplatelet effect of the latter drug is unknown. Preliminary information from spontaneous reporting systems indicates that there may be differences in the risk of cardiac failure and hypertension between standard NSAIDs and COX-2 inhibitors and between rofecoxib and celecoxib. More formal studies using equivalent doses are needed to test this observation. Use of COX-2 inhibitors may be considered in the elderly to reduce the risk of gastroduodenal complications associated with standard NSAIDs but only when consideration has first been given to use of less toxic medicines as alternatives or supplements, the appropriate dose of the COX-2 inhibitor or standard NSAID, the presence and possible impact of co-morbidities, and the implications of taking COX-2 inhibitors with any concomitant medications. Equally important is regular monitoring of the patient taking a COX-2 inhibitor for efficacy and adverse effects, and ensuring that the patient has a continuing need to keep taking the drug. Close attention also needs to be paid to intercurrent illnesses and new prescriptions that may reduce the safety of the COX-2 inhibitor. A standard NSAID plus a proton pump inhibitor may be equally effective as a COX-2 inhibitor in reducing the risk of gastroduodenal toxicity and if used the same prescribing advice applies. Current knowledge concerning the thrombotic potential of COX-2 inhibitors suggests that this combination, if tolerated, may be preferable to a COX-2 inhibitor, particularly where prolonged use is required. This knowledge also indicates that for patients with or at high risk of ischaemic heart disease or stroke, COX-2 inhibitors are contraindicated.

Clinical pharmacology of lumiracoxib, a second-generation cyclooxygenase 2 selective inhibitor

Although highly selective cyclooxygenase (COX)-2 inhibitors have been shown to be less toxic to the gastrointestinal tract than conventional non-steroidal anti-inflammatory drugs (NSAIDs), their overall safety profile is questioned. Since different selective COX-2 inhibitors were found to be associated with increased cardiovascular thrombotic events, the thrombotic hazard may be a class effect. Furthermore, warnings have been issued regarding serious skin and hypersensitivity reactions associated with valdecoxib. Lumiracoxib is a novel COX-2 selective inhibitor (coxib) with improved biochemical selectivity over that of currently available coxibs. It is structurally distinct from other drugs in the class and has weakly acidic properties. Clinical studies support a once-daily dosing regimen, despite its relatively short plasma elimination half-life (3 - 6 h). In randomised, controlled clinical trials, lumiracoxib 100 - 200 mg/day has been shown to be superior to placebo in patients with symptomatic osteoarthritis, with clinical efficacy similar to diclofenac 150 mg/day, celecoxib 200 mg/day or rofecoxib 25 mg/day. Furthermore, lumiracoxib 200 - 400 mg/day appeared to be effective in patients with rheumatoid arthritis. In patients with acute pain related to primary dysmenorrhoea, dental or orthopaedic surgery, lumiracoxib 400 mg/day was found to be at least as effective as standard doses of traditional NSAIDs and other coxibs. Endoscopic studies have indicated that lumiracoxib is associated with a rate of gastroduodenal ulcer formation that is significantly lower than with ibuprofen and does not differ from celecoxib. In the Therapeutic Arthritis Research and Gastrointestinal Trial, which enrolled 18,325 patients with osteoarthritis, the cumulative 1-year incidence of ulcer complications (primary end point) was significantly reduced by approximately threefold on lumiracoxib 400 mg/day compared with naproxen 1000 mg/day or ibuprofen 2400 mg/day (0.32 versus 0.91%). Reduction in ulcer complications was more pronounced in the population not taking low-dose aspirin (0.2 versus 0.92%, respectively). Conversely, the gastrointestinal advantage of lumiracoxib was abrogated in patients receiving low-dose aspirin (0.69 versus 0.88%, respectively, p = 0.49). Regarding cardiovascular events contributing to the trialists' composite end point (myocardial infarction, stroke or cardiovascular death), there was no significant difference between lumiracoxib (0.65%) versus combined comparator NSAIDs (0.55%). Similarly, no significant difference was recorded in rates of myocardial infarction (clinical and silent) between the lumiracoxib (0.25%) and the combined NSAID (0.19%) treatment groups. Liver function test abnormalities were more frequent with lumiracoxib (2.57%) than with the comparator NSAIDs (0.63%). Whether or not this would result in an increased risk of clinical hepatitis in the real world setting is unforeseeable.

Management of cancer pain

There are four basic approaches to cancer pain control: modify the source of pain, alter central perception of pain, modulate transmission of pain to the central nervous system, and block transmission of pain to the central nervous system. Systemic pharmacologic management aimed at the first three of these approaches is the cornerstone of the treatment of most cancer patients with moderate to severe pain. Optimal pharmacologic management of cancer pain requires selection of the appropriate analgesic drug; prescription of the appropriate dose; administration of the analgesic by the appropriate route; scheduling of the appropriate dosing interval; prevention of persistent pain and relief of breakthrough pain; aggressive titration of the dose of the analgesic; prevention, anticipation, and management of analgesic side effects; consideration of sequential trials of opioid analgesics; and use of appropriate co-analgesic drugs for specific pain syndromes. Most clinicians should be able to control most of the pain in most of their cancer patients. Collaboration with pain and hospice/palliative care experts should help the rest. No cancer patient should live or die with unrelieved pain.

Incidence of Thrombotic Cardiovascular Events in Patients Taking Celecoxib Compared with Those Taking Rofecoxib

BACKGROUND

Rofecoxib was withdrawn from the market worldwide because of concerns relating to cardiovascular safety. There is conflicting evidence as to whether celecoxib, the most popular alternative to rofecoxib, carries the same cardiovascular risks. This study's aim was to compare the incidence of thrombotic cardiovascular events in patients taking celecoxib with patients taking rofecoxib.

METHODS

Prescription event monitoring methodology was used in this prospective, longitudinal, observational cohort study, in which cohorts of patients were established from prescription data and thrombotic cardiovascular events were identified from follow-up questionnaires to patients' doctors and other sources.

SUBJECTS

New Zealand patients with at least one prescription for either rofecoxib or celecoxib between 1 December 2000 and 30 November 2001.

ANALYSIS

For this interim analysis the total cohorts were separated into three groups at different stages of follow-up: complete, incomplete and no follow-up. Cox's proportional hazards models were applied to calculate hazard ratios for celecoxib compared with rofecoxib.

RESULTS

The total cohorts included 26,403 patients receiving rofecoxib and 32,446 patients receiving celecoxib. 4882 (18%) rofecoxib and 6267 (19%) celecoxib patients had been completely followed up. In this group the unadjusted hazard ratio for celecoxib compared with rofecoxib was 1.07 (95% CI 0.59, 1.93). After adjustment for age this hazard ratio was 0.94 (95% CI 0.51, 1.70). Further adjustment for sex, 'as required' use, indication for use, concomitant NSAID use and pre-existing cardiovascular disease resulted in only minor changes to the hazard ratio.

CONCLUSION

This interim analysis of the Intensive Medicines Monitoring Programme data suggests that in 'real-life' postmarketing use in New Zealand there is no significant difference in the risk of cardiovascular thrombotic events in patients taking celecoxib compared with those taking rofecoxib.

Do Selective Cyclo-Oxygenase-2 Inhibitors Have a Future?

The dramatic withdrawal of rofecoxib on 30 September 2004, along with safety concerns about other cyclo-oxygenase (COX)-2 inhibitors (especially valdecoxib), raises important issues for clinicians, pharmaceutical companies and regulatory authorities. Some of these are examined in this article, including: (i) was the cardiotoxicity of rofecoxib evident long before its withdrawal?; (ii) is the thrombotic hazard a class effect that is applicable to all COX-2 inhibitors?; (iii) may conventional NSAIDs also confer a risk of cardiovascular thrombosis?; and (iv) is there any future for selective COX-2 inhibitors?

Safety profile of celecoxib as used in general practice in England: results of a prescription-event monitoring study

AIMS

A post-marketing surveillance study using the technique of Prescription Event Monitoring was undertaken to monitor the safety of celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, as prescribed in primary care in England.

METHODS

Patients were identified from dispensed British National Health Service prescription data supplied in confidence by the Prescription Pricing Authority for celecoxib between May and December 2000. Simple questionnaires were sent to the prescribing general practitioner at least 6 months after the date of the first dispensed prescription for each individual patient. Event incidence densities (IDs) [the number of 1st reports per 1000 patient-months of exposure (pme)] were calculated. ID differences for events reported in month 1 (ID1) and months 2-6 (ID2) were examined for temporal changes in event rate. Information on suspected adverse drug reactions (ADRs), reasons for stopping treatment, outcome of pregnancies and cause of death were also requested. Data were gathered on potential gastrointestinal (GI) risk factors [recent use of other non-steroidal anti-inflammatory drugs (NSAIDs), past history of upper GI disorders and concomitant gastro-irritant agents or anti-ulcer drugs]. Crude IDs per 1000 pme and ID ratios were calculated according to potential risk factors, and age (> or = 65 years, < or = 64 years).

RESULTS

The cohort comprised of 17,458 patients [median age 62 years (IQR 51,73); 68.3% female]. The most common specified indication was osteoarthritis (28.1%, n = 4905). Not effective was the event with the highest ID1 (139.9 per 1000 pme). The clinical events with the highest ID1 were dyspepsia (25.4 per 1000 pme) followed by abdominal pain (10.6). These were also given frequently as reasons for stopping (551 and 174 of 9126 reports). Of 436 events in 325 patients (1.9% of total cohort) that were reported as ADRs, the most frequent were events within the alimentary system (186 reports). Uncommon events reported during treatment (not necessarily as ADRs) included allergy (0.10%, n = 17), anaphylaxis (0.01%, n = 2), angioneurotic oedema (0.02%, n = 3) and bronchospasm (0.05%, n = 9). There were 103 reports of events associated with thromboembolism and 111 reports of serious GI events [90 GI bleeds (upper and lower); 21 peptic ulcers] received during treatment or within 1 month of stopping. A past history of dyspeptic/other upper GI conditions and use of concomitant gastro-protective drugs were each associated with a significantly increased risk of dyspepsia and abdominal pain.

CONCLUSIONS

Frequently reported adverse events were those GI events commonly associated with treatment with other NSAIDS. Stratification by identified risk factors suggested that channelling of high-risk patients is likely. Serious upper and lower GI events, and thromboembolic events did occur during this study, although the incidence was low (< 1%). Doctors should continue to prescribe NSAIDs, including COX-2-specific inhibitors, with caution.