Gastric perforation associated with the use of celecoxib

Targeting cyclooxygenase-2 in depression is not a viable therapeutic approach and may even aggravate the pathophysiology underpinning depression

Depression is a complex progressive disorder accompanied by activation of inflammatory and Th-1 driven pathways, oxidative and nitrosative stress (O&NS), lowered antioxidant levels, mitochondrial dysfunctions, neuroprogression and increased bacterial translocation. In depression, activation of immuno-inflammatory pathways is associated with an increased risk for cardio-vascular disorder (CVD). Because of the inflammatory component, the use of cyclooxygenase 2 (COX-2) inhibitors, such as celecoxib, has been advocated to treat depression. Electronic databases, i.e. PUBMED, Scopus and Google Scholar were used as sources for this selective review on the effects of COX-2 inhibitors aggravating the abovementioned pathways. COX-2 inhibitors may induce neuroinflammation, exacerbate Th1 driven responses, increase lipid peroxidation, decrease the levels of key antioxidants, damage mitochondria and aggravate neuroprogression. COX-2 inhibitors may aggravate bacterial translocation and CVD through Th1-driven mechanisms. COX-2 inhibitors may aggravate the pathophysiology of depression. Since Th1 and O&NS pathways are risk factors for CVD, the use of COX-2 inhibitors may further aggravate the increased risk for CVD in depression. Selectively targeting COX-2 may not be a viable therapeutic approach to treat depression. Multi-targeting of the different pathways that play a role in depression is more likely to yield good treatment results.

cPLA2 is protective against COX inhibitor-induced intestinal damage

Cytosolic phospholipase A(2) (cPLA(2)) is the rate-limiting enzyme responsible for the generation of prostaglandins (PGs), which are bioactive lipids that play critical roles in maintaining gastrointestinal (GI) homeostasis. There has been a long-standing association between administration of cyclooxygenase (COX) inhibitors and GI toxicity. GI injury is thought to be induced by suppressed production of GI-protective PGs as well as direct injury to enterocytes. The present study sought to determine how pan-suppression of PG production via a genetic deletion of cPLA(2) impacts the susceptibility to COX inhibitor-induced GI injury. A panel of COX inhibitors including celecoxib, rofecoxib, sulindac, and aspirin were administered via diet to cPLA(2)(-/-) and cPLA(2)(+/+) littermates. Administration of celecoxib, rofecoxib, and sulindac, but not aspirin, resulted in acute lethality (within 2 weeks) in cPLA(2)(-/-) mice, but not in wild-type littermates. Histomorphological analysis revealed severe GI damage following celecoxib exposure associated with acute bacteremia and sepsis. Intestinal PG levels were reduced equivalently in both genotypes following celecoxib exposure, indicating that PG production was not likely responsible for the differential sensitivity. Gene expression profiling in the small intestines of mice identified drug-related changes among a panel of genes including those involved in mitochondrial function in cPLA(2)(-/-) mice. Further analysis of enterocytic mitochondria showed abnormal morphology as well as impaired ATP production in the intestines from celecoxib-exposed cPLA(2)(-/-) mice. Our data demonstrate that cPLA(2) appears to be an important component in conferring protection against COX inhibitor-induced enteropathy, which may be mediated through affects on enterocytic mitochondria.

[Fraudulent pain research: a hurt so deep nothing can alleviate it]

Untruthfulness in research is reprehensible. Dr Scott S. Reuben, an anesthesiologist at Baystate Medical Center in Springfield, Massachusetts in the United States, a leader and pioneer in the field of multimodal analgesia, has been accused of fraud, specifically of having falsified results in at least 21 manuscripts published over a period of 15 years. This may come to be seen as one of the largest-scale and longest-running acts of medical research fraud ever. Apart from fabricated data, it seems the author committed other acts of misconduct. His coauthors have not been accused of wrongdoing, as they allege their names were falsely appended to the manuscript. The editors of the 2 most implicated journals, Anesthesiology and Anesthesia & Analgesia, have published editorials retracting the papers they judge to be fraudulent. Because Dr Reuben is a major figure in postoperative multimodal analgesia, many studies by other authors whose hypotheses have emerged from findings announced in the discredited papers may also now be considered contaminated by association. The definitions of scientific misconduct and the procedures for pursuing offenders vary greatly from country to country, creating a certain degree of uncertainty about how to proceed when we confront this problem. Beyond any possible legal liability that might arise, there are the questions of how fraud might affect patients' health or the medical knowledge base. Although the concept of multimodal analgesia may continue to be defended, we cannot be absolutely sure of its benefits without carrying out new clinical trials to repair the damage done by this act of misconduct.

Weekly administration of docetaxel in combination with estramustine and celecoxib in patients with advanced hormone-refractory prostate cancer: final results from a phase II study

The objective of this study was to evaluate the efficacy and safety profile of weekly docetaxel, estramustine and celecoxib in patients with advanced hormone-refractory prostate cancer. Forty-eight patients received 35 mg m⁻² of weekly docetaxel for 3 out of every 4 weeks, 280 mg of estramustine twice daily on days 1–3, 8–10, 15–17 and 400 mg of celecoxib twice daily until progression or toxicity. Cycles were repeated every 28 days for at least six cycles. Patients were evaluated for response and toxicity. Patients received a median of four cycles (range: 1–9). On an intention-to-treat analysis, prostate-specific antigen (PSA) was decreased greater than 50% in 28 out of 48 patients (overall response rate: 58%, 95% confidence interval (CI): 44–72) and median duration of PSA response was 8.0 months (95% CI: 6.9–9.0). After a median follow-up of 11.3 months, the median time to progression was 7.1 months and the median overall survival was 19.2 months. The most frequent severe toxicity was asthenia (15% of patients), diarrhoea and stomatitis (8% of patients, each). Grade 3/4 neutropenia was reported in two patients. There was a toxic death during the study due to a gastric perforation. Celecoxib with weekly docetaxel and estramustine is an effective and safe treatment for patients with hormone-refractory prostate cancer, but it does not seem to add any benefit to docetaxel.

Opioid-sparing effects of diclofenac and paracetamol lead to improved outcomes after cardiac surgery

OBJECTIVE

This study assessed the analgesic efficacy, side effects, time to extubation, and oxygenation of 3 analgesic regimens after coronary artery bypass surgery using diclofenac, paracetamol, and placebo suppositories.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study.

SETTING

Referral center for cardiothoracic surgery at a university hospital.

PARTICIPANTS

Sixty consenting adults scheduled for elective coronary artery bypass grafting (CABG).

INTERVENTIONS

Patients were divided into 3 groups postoperatively: diclofenac/paracetamol: diclofenac, 100 mg rectally, and paracetamol, 1 g rectally. Diclofenac was repeated after 18 hours and paracetamol every 6 hours for 24 hours; diclofenac: diclofenac as in diclofenac/paracetamol, with placebos replacing paracetamol; and placebo: 2 placebo suppositories at same times as diclofenac/paracetamol. All patients received morphine patient-controlled analgesia.

RESULTS

Twenty-four hour morphine consumption with diclofenac/paracetamol was 12 +/- 6 mg, diclofenac 22 +/- 13 mg, and placebo 37 +/- 15 mg (diclofenac/paracetamol and diclofenac, p = 0.0003 and p = 0.0159 compared with placebo). Patients in the placebo group had significantly greater pain scores at 12 and 24 hours compared with diclofenac/paracetamol and diclofenac. Extubation time was significantly prolonged in the placebo group compared with the diclofenac/paracetamol and diclofenac groups (mean [SD] minutes diclofenac/paracetamol, diclofenac, and placebo 478 [150], 487 [257], and 710 [326], respectively). Oxygenation following extubation was significantly lower in the placebo group compared with the diclofenac/paracetamol and diclofenac groups (mean [SD] mmHg: diclofenac/paracetamol, diclofenac, and placebo 175 [44], 157 [43], and 117 [22], respectively). Episodes of nausea and vomiting were significantly less in the diclofenac/paracetamol and diclofenac groups than in the placebo group (46% and 51% reduction, respectively). all groups had similar blood loss and change in serum creatinine.

CONCLUSION

Diclofenac alone or with paracetamol has a significant opioid-sparing effect after CABG, producing more rapid extubation and better oxygenation.

The ever-emerging anti-inflammatories. Have there been any real advances?

Gastrointestinal (GI) Adverse Drug Reactions (ADRs) from the NSAIDs are a major cause of morbidity and mortality in arthritic patients taking these drugs. The recent much heralded development of COX-2 selective drugs (celecoxib, rofecoxib), the objective of which has been to spare inhibition of the production of COX-1 derived mucosal protective prostaglandins, may have represented an advance in reducing the risk of serious ADRs--ulcers and bleeding--but does not appear to have reduced the incidence of symptomatic side-effects (nausea, vomiting, epigastric pain/heartburn, abdominal discomfort) which are a major reason for withdrawal from NSAID therapy, especially in the long term. The rationale of COX-2 selectivity from these newer drugs is controversial since there may be pharmacokinetic differences from established carboxylate-NSAIDs that accounts for their apparent lower ulcerogenicity. Moreover, concerns have been recently expressed that as COX-2 is important in ulcer healing, control of prostacyclin production and renal function that they may have adverse reactions from these effects. Indeed, recent reports of enhanced risk of congestive heart failure with rofecoxib are of importance and may relate to impaired prostacyclin production. Moreover, there are other therapeutic strategies that have yielded equally low ulcerogenic NSAIDs (e.g. the prodrug, nabumetone; the established COX-2 inhibitory drug, nimesulide) and even the well-established NSAIDs ibuprofen and diclofenac have relatively low upper GI ulcerogenicity and have been used as benchmark standards in comparative trials of the newer "Oxib" drugs (celecoxib, rofecoxib). Much research interest has centred on the nitric oxide-donating NSAIDs (NO-NSAIDs). The rationale for donating NSAIDs being to counteract the vasoconstriction effects of NSAIDs but this has yet to be fully evaluated. It is not certain that this "antidote" approach will be acceptable as there may also be systemic effects of the nitrobutoxyl--or other NO-donors that may have toxicological consequences. Another strategy is the development of mixed COX-5 lipoxygenase (LOX) inhibitors--the progenitors of which were benoxaprofen and BW-755C. The rationale of reducing the potential for lipoxygenase mediated actions in the stomach (e.g. vasoconstriction, leucocyte accumulation). Clearly, the need to develop newer NSAIDs with lower risks of ulcers and bleeding as well as symptomatic ADRs is still representing a major challenge.

Celecoxib: a new option in the treatment of arthropathies and familial adenomatous polyposis

The discovery of the two isoenzymes of cyclooxygenase (COX) has recently lead to the development and clinical introduction of specific inhibitors of cyclooxygenase-2 (COX-2), such as celecoxib, onto the market. Celecoxib is an effective anti-inflammatory, analgesic and antipyretic agent therapeutically utilised in the management of osteoarthritis and rheumatoid arthritis. In addition, celecoxib has some novel therapeutic and pharmacological activities. Celecoxib inhibits anti-apoptotic kinase activation and is the first specific COX-2 inhibitor to be marketed for familial adenomatous polyposis, an inheritable predisposition for colorectal cancer. Celecoxib is not without gastrointestinal (GI) side effects but demonstrates markedly reduced GI ulceration in clinical trials when compared to traditional non-specific non-steroidal anti-inflammatory drugs (NSAIDs). The specific COX-2 inhibitors each have distinctive pharmacokinetic properties. Celecoxib can be given either once or twice daily. Racial differences in drug disposition, and pharmacokinetic changes in elderly patients, patients with chronic renal insufficiency and patients with mild to moderate hepatic impairment, are evident with celecoxib. Despite the specific action of these drugs, there remains the potential for significant drug interactions. Celecoxib has demonstrated interactions with fluconazole, lithium and warfarin. Increased clinical vigilance should be maintained when co-prescribing medications with celecoxib until further clinical experience is gained. Celecoxib represents a major therapeutic advance in terms of GI safety. However, long-term safety in other organ systems, safety with concomitant drug administration, and pharmacoeconomic benefits still remain to be proven.

The "aspirin" of the new millennium: cyclooxygenase-2 inhibitors

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandin synthesis via the cyclooxygenase (COX) enzyme, the key to both therapeutic benefits and toxicity. COX enzyme exists in 2 isoforms, COX-1 and COX-2. COX-1 enzyme is thought to mediate "housekeeping" or homeostatic functions, and COX-2 is considered an inducible enzyme in response to injury or inflammation. COX-2 inhibitors are the "next-generation" NSAIDs that may selectively block the COX-2 isoenzyme without affecting COX-1 function. This may result in control of pain and inflammation with a lower rate of adverse effects compared with older nonselective NSAIDs. Rapidly evolving evidence suggests that COX-2 enzyme has a diverse physiologic and pathologic role. This article addresses the role of COX-2 enzyme in health and disease as well as the potential therapeutic value and safety issues related to COX-2 inhibition.

Nonsteroidal anti-inflammatory drugs in the elderly

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in the elderly for the treatment of fever, pain, pain associated with inflammation in rheumatoid arthritis and osteoarthritis, neuromuscular disorders, headache, and musculoskeletal conditions. Each year in the United States, people spend 5 to 10 billion dollars to purchase prescription and over-the-counter NSAIDs. Gastrointestinal side effects such as ulcers and bleeding are the most prevalent and life-threatening problems associated with NSAIDs. Specifically in the elderly, NSAIDs have become a leading cause of hospitalization and may increase the risk of death from ulceration more than 4-fold. NSAIDs and the new class of cyclo-oxygenase-2 selective NSAIDs continue as drugs of choice for analgesia and anti-inflammatory effects. Physiological changes of aging worsen the side-effect profile of NSAIDs in the elderly. These side effects, when added to the increased potential for drug interactions, lead to a much greater risk for adverse outcomes when NSAIDs are used in the elderly patient. The similarities and differences in the NSAID agents warrant review in light of the newer drugs--celecoxib and rofecoxib--with their expected improvement in gastrointestinal side effects. This article reviews current information about using NSAIDs in elderly persons.

Clinical pharmacokinetics and pharmacodynamics of celecoxib: a selective cyclo-oxygenase-2 inhibitor

Celecoxib, a nonsteroidal anti-inflammatory drug (NSAID), is the first specific inhibitor of cyclo-oxygenase-2 (COX-2) approved to treat patients with rheumatism and osteoarthritis. Preliminary data suggest that celecoxib also has analgesic and anticancer properties. The selective inhibition of COX-2 is thought to lead to a reduction in the unwanted effects of NSAIDs. Upper gastrointestinal complication rates in clinical trials are significantly lower for celecoxib than for traditional nonselective NSAIDs (e.g. naproxen, ibuprofen and diclofenac). The rate of absorption of celexocib is moderate when given orally (peak plasma drug concentration occurs after 2 to 4 hours), although the extent of absorption is not known. Celexocib is extensively protein bound, primarily to plasma albumin, and has an apparent volume of distribution of 455+/-166L in humans. The area under the plasma concentration-time curve (AUC) of celecoxib increases in proportion to increasing oral doses between 100 and 800mg. Celecoxib is eliminated following biotransformation to carboxylic acid and glucuronide metabolites that are excreted in urine and faeces, with little drug (2%) being eliminated unchanged in the urine. Celecoxib is metabolised primarily by the cytochrome P450 (CYP) 2C9 isoenzyme and has an elimination half-life of about 11 hours in healthy individuals. Racial differences in drug disposition and pharmacokinetic changes in the elderly have been reported for celecoxib. Plasma concentrations (AUC) of celecoxib appear to be 43% lower in patients with chronic renal insufficiency [glomerular filtration rate 2.1 to 3.6 L/h (35 to 60 ml/min)] compared with individuals with healthy renal function, with a 47% increase in apparent clearance. Compared with healthy controls, it has been reported that the steady-state AUC is increased by approximately 40% and 180% in patients with mild and moderate hepatic impairment, respectively. Celecoxib does not appear to interact with warfarin, ketoconazole or methotrexate; however, clinically significant drug interactions with fluconazole and lithium have been documented. As celecoxib is metabolised by CYP2C9, increased clinical vigilance is required during the coadministration of other substrates or inhibitors of this enzyme.