Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclooxygenase (COX) is a key enzyme in the conversion of arachidonic acid to prostaglandins. Two isoforms of COX are known: COX-1 and COX-2. In the present study, the modulatory effect of COX-2 on glycine- and glutamate-induced ion currents in periaqueductal gray (PAG) neurons was investigated using the nystatin-perforated patch clamp method. Continuous application of lipopolysaccharides on PAG neurons resulted in increased glycine-induced ion current and decreased glutamate-induced ion current. In contrast, continuous application of celecoxib, selective COX-2 inhibitor, resulted in decreased glycine-induced ion current and increased glutamate-induced ion current. These results demonstrate that COX-2 modulates neuronal activity of PAG, and it can be suggested that COX-2 participates in the regulation of the descending pain control system in the level of PAG neurons.
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PMID:Modulation of cyclooxygenase-2 on glycine- and glutamate-induced ion currents in rat periaqueductal gray neurons. 1246 96

Etoricoxib is a cyclo-oxygenase (COX)-2-selective NSAID with a higher COX-1 to COX-2 selectivity ratio than the other COX-2-selective NSAIDs rofecoxib, valdecoxib or celecoxib. In patients with rheumatoid arthritis, improvements in tender and swollen joint counts and patient and investigator global assessment of disease activity were significantly greater in etoricoxib than in placebo recipients in two studies. Etoricoxib was also significantly more effective than naproxen in one of these studies. In patients with osteoarthritis of the hip or knee, etoricoxib was significantly more effective than placebo and had similar efficacy to naproxen with regards to improvements in pain and physical function scores and patient global assessment of disease status scores in two studies. Etoricoxib had similar efficacy to diclofenac in patients with osteoarthritis of the knee. Single-dose etoricoxib relieved pain in patients with postoperative dental pain in two studies. Similar scores assessing total pain relief over 8 hours (TOPAR8) were reported in etoricoxib and naproxen sodium or ibuprofen recipients, and higher TOPAR8 scores were reported with etoricoxib than with paracetamol (acetaminophen)/codeine. Pain relief was significantly better with etoricoxib than placebo in two studies in patients with chronic low back pain. Etoricoxib had similar efficacy to indomethacin in a study in patients with acute gout, and single-dose etoricoxib had similar efficacy to naproxen sodium in a study in women with primary dysmenorrhoea. Compared with non-COX-selective NSAIDs, etoricoxib was associated with significantly fewer upper gastrointestinal (GI) perforations, ulcers or bleeds, and was significantly less likely to result in treatment discontinuation because of NSAID-type GI symptoms or any GI symptoms.
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PMID:Etoricoxib. 1246 2

The discovery of two cyclooxygenase (COX)-isoenzymes, a constitutive COX-1, serving homeostatic prostanoid synthesis, and an inducible COX-2, responsible for proinflammatory prostanoid production, led to the development of new non-steroidal anti-inflammatory drugs (NSAIDs), the selective COX-2 inhibitors, promising minimal NSAID-typical toxicity with full anti-inflammatory efficacy. So far, the strategy of selective COX-2 inhibition has been successful. Selective COX-2 inhibitors have significantly less gastrotoxicity and no effects on platelet aggregation. However, with regard to renal adverse events, selective COX-2 inhibitors do not offer a clinically relevant advantage over non-selective inhibitors. Moreover, concerns over the cardiovascular risk of selective COX-2 inhibitors have recently been raised. The second generation of COX-2 inhibitors with higher COX-2 selectivity was developed with the promise of further reduction of NSAID-typical adverse effects. The leading compounds are valdecoxib, parecoxib, etoricoxib and lumaricoxib. At the present time they have proven efficacy for the treatment of pain and inflammation. Parecoxib as a parenteral, highly selective COX-2 inhibitor has the potential to become the NSAID of choice for treatment of postoperative pain. In clinical trials, valdecoxib, parecoxib, etoricoxib and lumaricoxib have caused no more endoscopic ulcers than placebo. However, to date, no data on the clinically relevant endpoints perforation, symptomatic ulcer and bleeding are available. Furthermore, no definite conclusions on renal and cardiovascular safety are possible. Current evidence points to a marginal, if any, gain of safety compared with the first generation of COX-2 inhibitors. However, trials with the new COX-2 inhibitors offer the chance to address these open questions of highly selective COX-2 inhibition; that is, thrombogenic risk, sodium and water retention, and interference with tissue repair, in particular, healing of mucosal damage.
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PMID:The second generation of COX-2 inhibitors: what advantages do the newest offer? 1248 21

The discovery of the two isoenzymes of cyclooxygenase COX-1 and COX-2 and their separate functions, localization and regulation, has initiated the search for new and more selective inhibitors of prostaglandin biosynthesis. Selective COX-2 inhibitors were developed in order to improve an anti-inflammatory and analgesic specificity and potency. The role of inducible COX-2 at the peripheral site of inflammation is well known. The discovery of COX-2 in the spinal cord suggests that it is responsible for spinal prostaglandin release in nociceptive processes following a peripheral inflammatory stimulus. In the future, selective COX-2 inhibitors such as celecoxib (GD Searle & Co), rofecoxib (Merck & Co Inc) and the recently developed etoricoxib (Merck & Co Inc) may play an important role in the treatment of a wider range of pain conditions in addition to their present use as anti-inflammatory and analgesic drugs.
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PMID:COX-2 inhibition and the control of pain. 1249 12

Among the most widely prescribed drugs worldwide, non-steroidal anti-inflammatory drugs (NSAIDs) are effective for relieving pain, but they are also associated with a high incidence of gastrointestinal (GI) adverse events. Both the beneficial and harmful effects of NSAIDs result from inhibition of the cyclo-oxygenase (COX) enzyme. Recognition of the two distinct COX isoforms prompted development of drugs that selectively block the activity of COX-2, thus providing pain relief and reducing inflammation while sparing COX-1, the enzyme apparently responsible for most protective prostaglandin synthesis in the mucosa of the stomach and duodenum. The results of preclinical and clinical studies indicate that COX-2 inhibitors exhibit high selectivity in inhibiting COX-2, provide excellent pain relief, and cause significantly less GI toxicity than do conventional nonselective NSAIDs. Although they represent a significant advance over nonselective NSAIDs, selective COX-2 inhibitors are not without limitations. They do not completely eliminate GI toxicity or the renal side effects associated with use of conventional NSAIDs. Moreover, in cases of inflammation or ulceration in the GI tract, COX-2 inhibition may delay ulcer healing. Finally, case reports and the results of animal experiments suggest that COX-2 inhibitors may adversely affect ovulation and cause a tendency towards prothrombotic events.
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PMID:Do selective cyclo-oxygenase inhibitors eliminate the adverse events associated with nonsteroidal anti-inflammatory drug therapy? 1257 27

Cyclooxygenases-1 and -2 (COX-1 and COX-2, also known as prostaglandin H2 synthases-1 and -2) catalyze the committed step in prostaglandin synthesis. COX-1 and -2 are of particular interest because they are the major targets of nonsteroidal antiinflammatory drugs (NSAIDs) including aspirin, ibuprofen, and the new COX-2-selective inhibitors. Inhibition of the COXs with NSAIDs acutely reduces inflammation, pain, and fever, and long-term use of these drugs reduces the incidence of fatal thrombotic events, as well as the development of colon cancer and Alzheimer's disease. In this review, we examine how the structures of COXs relate mechanistically to cyclooxygenase and peroxidase catalysis and how alternative fatty acid substrates bind within the COX active site. We further examine how NSAIDs interact with COXs and how differences in the structure of COX-2 result in enhanced selectivity toward COX-2 inhibitors.
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PMID:The structure of mammalian cyclooxygenases. 1257 66

The role of the coxibs in the management of osteoarthritis and rheumatoid arthritis has been widely discussed, but there are other potential applications for the coxibs that have received less attention. Here we consider the use of the coxibs in acute pain syndromes such as primary dysmenorrhea and the pain associated with dental extraction, as well as considering their application in chronic low back pain and cancer pain. Another area where the coxibs may prove particularly beneficial is in the management of post-surgical pain. Traditional post-surgical analgesia has involved the use of non-selective NSAIDs and opioids, but these agents can be associated with side effects such as post-operative bleeding, gastrointestinal problems, nausea, and constipation. Because the coxibs do not inhibit COX-1 dependent platelet aggregation like traditional NSAIDs, the risk of post-surgical bleeding is reduced. The careful application of coxibs as part of a multi-modal approach to pain management in the perioperative period can reduce the requirement for opioid medications and thus reduce the risk of post-operative complications such as ileus. In the future, coxibs are likely to play an important role in multi-modal perioperative analgesic regimens with the aim of reducing post-operative periods of convalescence.
J Pain Symptom Manage 2003 Feb
PMID:Strategies in pain management: new and potential indications for COX-2 specific inhibitors. 1260 54

Although the coxibs have demonstrated superior gastrointestinal safety compared to traditional non-selective NSAIDs, questions remain regarding their effects on the renal and cardiovascular systems. In terms of renal function, both Type 1 and Type 2 cyclooxygenase (COX-1 and COX-2) are expressed constitutively in the kidney. Prostaglandins do not play a major role in the maintenance of renal function in healthy individuals but they become profoundly important in certain clinical situations such as renal stress, or volume depletion. In such situations the effects of the coxibs and non-selective NSAIDs are likely to be similar. The incidence of renal side effects is low (1-5%) and the patients at risk of renal complications are well defined and can usually be identified prospectively and followed up as appropriate. From the cardiovascular point of view, questions have been raised as to whether the coxibs have a prothrombotic effect. Here we review the available evidence and consider various hypotheses for an apparent increase in cardiovascular events reported in one coxib study (the VIGOR trial). Because of a lack of anti-platelet activity, coxibs are not suited for the provision of cardiovascular prophylaxis, and in patients at risk of myocardial infarction the prophylactic use of aspirin should always be considered. Although evidence suggests that use of coxibs with low-dose aspirin is safer than the combination of traditional NSAIDs with aspirin, further studies are required to confirm that this is the case.
J Pain Symptom Manage 2003 Feb
PMID:Coxibs--beyond the GI tract: renal and cardiovascular issues. 1260 56

Non-steroidal anti-inflammatory drugs (NSAIDs) suppress the activity of both isoforms of cyclo-oxygenase (COX). Inhibition of COX-1, the constitutive isoform, is primarily responsible for the adverse gastrointestinal effects of the NSAIDs whereas inhibition of COX-2, the inducible isoform, accounts for their therapeutic effects. COX-2 inhibitors such as celecoxib and rofecoxib appear to be as effective as non-selective NSAIDs in the treatment of chronic inflammatory disease but their analgesic efficacy and their safety at the higher doses required for analgesia are less certain. There is consistent evidence that COX-1 plays a major role in the early pain response following injury and that analgesia is increased when both COX-1 and COX-2 are inhibited simultaneously. Early postoperative nociception may cause hyperalgesia at a later time by a process of central plasticity. In an experimental model of pain, ibuprofen promptly suppresses prostaglandin E2 concentrations whereas celecoxib has no discernible effect until 90-120 minutes postoperatively, when COX-2 activity is induced. Both drugs significantly reduce pain compared with placebo but celecoxib appears to have a slower onset of action. The analgesic effect of ibuprofen is well characterised for acute pain and short-term treatment is well tolerated.
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PMID:Relative efficacy of selective COX-2 inhibitors compared with over-the-counter ibuprofen. 1272 42

Non steroidal anti-inflammatory drugs (NSAIDs) are still the most commonly used remedies for rheumatic diseases. But NSAIDs produce serious adverse effects, the most important being gastric injury up to gastric ulceration and renal damage. Several strategies have been adopted in order to avoid these shortcomings, especially gastrointestinal toxicity. So, non steroidal anti-inflammatory drugs have been associated with gastroprotective agents that counteract the damaging effects of prostaglandin synthesis suppression: however, a combination therapy introduces problems of pharmacokinetics, toxicity, and patient s compliance. Also incorporation of a nitric oxide (NO)-generating moiety into the molecule of several NSAIDs was shown to greatly attenuate their ulcerogenic activity: however, several findings suggest a possible involvement of NO in the pathogenesis of arthritis and subsequent tissue destruction. A most promising approach seemed to be the preparation of novel NSAIDs, specific for the inducible isoform of cyclooxygenase (COX-2): they appear to be devoid of gastrointestinal toxicity, in that they spare mucosal prostaglandin synthesis. However, a number of recent studies raised serious questions about the two central tenets that support this approach, namely that the prostaglandins that mediate inflammation and pain are produced solely via COX-2 and that the prostaglandins that are important in gastrointestinal and renal function are produced solely via COX-1. So, increasing evidence shows that COX-2 (not only COX-1) also plays a physiological role in several body functions and that, conversely, COX-1 (not only COX-2) may also be induced at sites of inflammation. Moreover, COX-2 selective NSAIDs have lost the cardiovascular protective effects of non-selective NSAIDs, effects which are mediated through COX-1 inhibition (in addition, COX-2 has a role in sustaining vascular prostacyclin production). The products generated by the 5-lipoxygenase pathway (leukotrienes) are particularly important in inflammation: indeed, leukotrienes increase microvascular permeability and are potent chemotactic agents; moreover, inhibition of 5-lipoxygenase indirectly reduces the expression of TNF-alpha (a cytokine that plays a key role in inflammation). This explains the efforts to obtain drugs able to inhibit both 5-lipoxygenase and cyclooxygenases: the so-called dual acting anti-inflammatory drugs. Such compounds retain the activity of classical NSAIDs, while avoiding their main drawbacks, in that curtailed production of gastroprotective prostaglandins is associated with a concurrent curtailed production of the gastro-damaging and bronchoconstrictive leukotrienes. Moreover, thanks to their mechanism of action, dual acting anti-inflammatory drugs could not merely alleviate symptoms of rheumatic diseases, but might also satisfy, at least in part, the criteria of curative drugs. Indeed, leukotrienes are pro-inflammatory, increase microvascular permeability, are potent chemotactic agents and attract eosinophils, neutrophils and monocytes into the synovium. Finally, recent data strongly suggest that dual inhibitors may have specific protective activity also in neurodegeneration.
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PMID:Selective COX-2 inhibitors and dual acting anti-inflammatory drugs: critical remarks. 1273 82


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