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)

The release of prostanoids from rat brain, gastric mucosa, lungs and kidneys incubated ex vivo has been investigated for up to 5 h after oral administration of 10 mg/kg lysine clonixinate or 1 mg/kg ketorolac tromethamine. Additionally, 60 min after drug administration, a time point of near-maximal inhibition of prostanoid release, the effects of 2.5, 10 and 30 mg/kg lysine clonixinate and of 0.0225, 0.15 and 1 mg/kg ketorolac tromethamine were compared. In all organs investigated both drugs inhibited fatty acid cyclooxygenase (COX) in a dose-dependent manner, but ketorolac tromethamine was more potent and had a longer-lasting effect than lysine clonixinate. While the ID50 values for lysine clonixinate were in the same order of magnitude for all 4 organs investigated, ketorolac tromethamine exhibited some organ selectivity with a particularly high activity in the kidneys. This effect might be related to the renal toxicity of ketorolac tromethamine. On the other hand, the difference in potency was smallest in brain suggesting that inhibition of central prostanoid biosynthesis could contribute to the rapid and effective inhibition of pain by both drugs. IC50 values for inhibition of purified COX-1 and COX-2 in vitro were slightly lower for lysine clonixinate (2.4 and 24.6 micrograms/ml, respectively) than for ketorolac tromethamine (3.7 and 25.6 micrograms/ml, respectively).
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PMID:Effects of lysine clonixinate and ketorolac tromethamine on prostanoid release from various rat organs incubated ex vivo. 760 99

Non-steroidal antiinflammatory drugs (NSAIDs) are commonly used for the treatment of inflammation, pain, and fever. Mechanistically, these compounds are believed to act via inhibition of the enzyme cyclooxygenase (COX), which catalyzes the conversion of arachidonic acid to the prostaglandins (PGs). Although commercially available NSAIDS are efficacious antiinflammatory agents, significant side effects limit their use. Recently two forms of COX were identified- a constitutively expressed COX-1 and a cytokine-inducible COX-2. Commercially available NSAIDs like indomethacin inhibit both COX-1 and COX-2 suggesting the hypothesis that toxicities associated with NSAID therapy are due to inhibition of the non-regulated or constitutive form of COX (COX-1) in normal tissues, whereas therapeutic benefit derives from inhibition of the inducible enzyme, COX-2, at the site of inflammation. Therefore, a selective inhibitor of COX-2 may be anti-inflammatory without GI toxicity-providing a significant improvement over currently available NSAIDs.
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PMID:Mediation of inflammation by cyclooxygenase-2. 761 Sep 90

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of agents with similar actions but diverse chemical structures. Aspirin (acetylsalicylic acid) and sodium salicylate were the first drugs of this type to be used clinically. However, over the past 3 decades there has been a dramatic increase in the number of NSAIDs available for the treatment of postoperative pain. Tissue injury, such as occurs with surgical intervention, is associated with the release of numerous inflammatory mediators including prostaglandins. Prostaglandins derived from the arachidonic acid cascade are implicated in the production of inflammatory pain, and in sensitising nociceptors to the actions of other mediators. They are synthesised from arachidonic acid via the endoperoxide biosynthesis pathway, the initial step of which is catalysed by the enzyme cyclo-oxygenase. Two forms of the cyclo-oxygenase enzyme (COX-1 and COX-2) have been characterised. COX-1 is important in circumstances where prostaglandins have a protective effect such as gastric mucus production and renal blood flow maintenance. NSAIDs inhibit the synthesis of prostaglandins at 1 or more points in the endoperoxide pathway. Three mechanisms of inhibition of the biosynthetic enzymes have been proposed: (i) rapid, reversible competitive inhibition; (ii) irreversible, time-dependent inhibition; and (iii) rapid, reversible noncompetitive (free radical trapping) inhibition. In addition, there is evidence that NSAIDs have a central antinociceptive mechanism of action that augments the peripheral effect. This may involve inhibition of central nervous system prostaglandins or inhibition of excitatory amino acids or bradykinins. There is considerable variability in the pain relief obtained from NSAIDs. Such variability in drug response may be explained in terms of differences between agents with respect to either pharmacodynamic actions or pharmacokinetic parameters or a combination of both. Stereoisomerism, where preparations exist as racemic mixtures and where only 1 enantiomer is active, may also be important. However, chiral inversion from inactive to active enantiomer may occur and may be rapid or slow. NSAIDs have numerous adverse effects. Gastrointestinal disturbances including ulceration are the commonest adverse responses to NSAIDs and carry the greatest risk of death. Also significant are renal impairment and an increased risk of postoperative haemorrhage. Asthma and allergic reactions are uncommon.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Nonsteroidal anti-inflammatory drugs in perisurgical pain management. Mechanisms of action and rationale for optimum use. 770 16

Inducible cyclooxygenase-2 (COX-2), but not constitutive COX-1, can be upregulated in rheumatoid synovial tissue by interleukin-1 beta and phorbol esters and is inhibited by dexamethasone. This supports the role of COX-2 in acute inflammation in arthritis. Selective inhibition of COX-2 by non-steroidal anti-inflammatory drugs (NSAIDs) has been proposed as an approach to reduce their associated side effects while maintaining efficacy. The improved safety profile of selective COX-2 inhibitors will allow more widespread and sustained use than is currently possible with standard NSAIDs. In rheumatoid arthritis they may be used as effective symptomatic relief, in combination with disease modifying therapy at an early stage of disease. In osteoarthritis, and, more particularly, soft tissue rheumatism, pain contributes to the development of chronic disease, therefore the main benefit of selective COX-2 inhibition will be to provide safe, effective pain relief to maintain mobility and reduce disability.
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PMID:Clinical implications of selective cyclooxygenase-2 inhibition. 862 78

Pain is the main reason prompting patients to consult their physicians. In acute conditions, pain has a very particular significance as a warning sign, enabling the physician to attempt a diagnosis. Nevertheless, its detrimental effect upon the individual (even in the case of acute pain) and its cost to society are now widely acknowledged. There can be no doubt about the physical component of pain, but the psychological and social aspects should not be ignored, particularly in the case of chronic pain. There is no single therapeutic approach to pain and, more often than not, successful treatment comprises a combination of several. Pharmacological treatments are undeniably the most common approach. In clinical practice, recent advances have been based upon an improved understanding of 'old' substances such as morphine and, at the same time, research continues in the hope of finding the 'ideal' analgesic-effective in most situations but without adverse effects: this appears to be a somewhat utopian arm at present, considering the number of different causes of pain. An improved understanding of the physiological mechanisms of pain has led, within the field of clinical practice, to several methods of differentiating pain. These depend on whether or not pain responds to morphine, or on the type of pain: pain due to an excess of nociception, pain resulting from deafferentation (caused by damage to nerve pathways) in the central or peripheral nervous system and psychogenic (idiopathic) pain. Likewise, there are several different ways of classifying analgesic treatments: according to the intensity of pain, as with use of the WHO ladder (which is based on the notion of steps) for the treatment of cancer pain; according to the presumed physiopathological mechanism and, in particular, the response to morphine, and according to the presumed central or peripheral mechanism of the drugs. In reality, peripherally acting drugs can also have a central mechanism of action, just as drugs known to have a central mechanism of action can also have peripheral activity. As a result, several therapeutic classes have been identified. Firstly NSAIDs, which act by inhibiting the enzymes that synthesise prostaglandins, cyclooxygenases (COX-1, COX-2), but which also act upon lipo-oxygenases: Their efficacy is interesting, although somewhat limited by both their ceiling effect and the frequent adverse gastrointestinal reactions they produce. Specific inhibitors of COX-2 could well reduce the risk of adverse effects. Opioids constitute the first-line treatment for pain, particularly severe pain. There are several classifications for these drugs. Firstly, weak opioids (such as codeine) and strong opioids (such as morphine) are differentiated. Secondly, a distinction is made between pure agonists (such as morphine), partial agonists (such as buprenorphine), agonist-antagonists (such as nalbuphine) and antagonists (such as naloxone). Finally, agents are distinguished on the basis of their chemical structure (synthetic, semi-synthetic or natural derivatives). These molecules act upon different receptors (mu, delta, kappa, sigma) and, although peripheral mechanisms have been described, their activity occurs mainly at spinal and supraspinal levels. They provide a potent analgesic effect but are also responsible for various adverse effects-nausea, vomiting, sedation, constipation and respiratory depression-which seriously limit their use. As long as the indication is appropriate, these drugs should not be withheld because of fear of dependence or abuse. It has been observed that other adjuvant therapeutic approaches, generally used to treat conditions other than pain, provide pain relief in certain situations. These include corticosteroids, which are-widely used in rheumatology and oncology, and antidepressants, which are frequently used to treat chronic pain, especially that with a neuropathic component. Anti-epileptics are also used, particularly for excrutiating
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PMID:[Review of current pharmacologic treatment of pain]. 919 Mar 20

Nonsteroidal antiinflammatory drugs (NSAIDs) exert their actions by inhibiting cyclooxygenase (COX). It has recently been postulated that NSAIDs' antiinflammatory efficacy arises from inhibition of the COX-2 isoform of cyclooxygenase, whereas inhibition of the COX-1 isoform produces the troublesome and sometimes serious gastric and renal side effects of NSAIDs. A relatively selective COX-2 inhibitor, such as meloxicam, may combine antiinflammatory efficacy with improved tolerability. In volunteers, indomethacin 75 mg, but not meloxicam 7.5 mg, inhibited renal prostaglandin E2 excretion and platelet aggregation (COX-1 mediated effects). Double-blind, randomized trials in osteoarthritis and rheumatoid arthritis patients have shown equivalent antiinflammatory efficacy among meloxicam 7.5 mg or 15 mg and diclofenac 100 mg, naproxen 750 mg, and piroxicam 20 mg. In a double-blind, placebo-controlled trial, meloxicam (7.5 or 15 mg) caused less endoscopically detected gastrointestinal (GI) damage (Lanza scale) than piroxicam 20 mg. The MELISSA study, a double-blind, randomized, 28-day trial in over 9,000 patients showed that meloxicam 7.5 mg caused statistically less total GI toxicity, dyspepsia, abdominal pain, nausea and vomiting, and diarrhea than diclofenac 100 mg, despite equivalent reductions in pain on movement for each treatment. A global safety analysis of clinical trials, representing over 5,600 patients and comprising 170 and 1,100 patient-years of exposure for meloxicam 7.5 mg and 15 mg, respectively, showed that meloxicam caused less GI toxicity and fewer peptic ulcers and GI bleeds than naproxen, diclofenac, or piroxicam. The renal safety profile and incidence of liver function abnormalities with meloxicam is equivalent to other NSAIDs available for clinical use. In conclusion, relatively selective COX-2 inhibition exemplified by meloxicam may offer effective symptom relief with an improved GI tolerability profile.
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PMID:Meloxicam: selective COX-2 inhibition in clinical practice. 921 16

Pain is the major symptom that leads patients to consult their physicians for the treatment of arthritis; therefore, effective pain control is an important goal in the management of this disorder. Pharmacologic therapy begins with simple analgesics and education. In many patients, simple analgesics do not adequately control moderate arthritis pain, and nonsteroidal antiinflammatory drugs (NSAID) are substituted for or added to the analgesic therapy. While NSAID are effective in controlling pain in mild to moderate osteoarthritis (OA), they are associated with significant toxicity (most frequently gastrointestinal) and may even cause complications that result in death. Patients who experience the pain associated with arthritis would therefore benefit from the antiinflammatory and analgesic actions of agents that are devoid of significant toxicities. Cyclooxygenase-2 (COX-2) inhibitors are being evaluated in clinical trials or are in development. These agents appear to inhibit only the COX-2 isoenzyme, which is produced largely during inflammation and is responsible for the biosynthesis of prostaglandins and other mediators of inflammation as well as sensitizers to pain. Because COX-2 inhibitors do not inhibit COX-1 isoenzyme activity at pharmacologic concentrations, they are devoid of many of the toxicities that are typical side effects of NSAID. Short term studies in dental pain, OA, and rheumatoid arthritis found that the COX-2 inhibitor celecoxib was an effective analgesic but did not cause gastroduodenal erosions. It has the potential to provide analgesia and antiinflammatory action in patients with arthritis without the side effects of NSAID. Further studies are required to substantiate these findings.
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PMID:Pain management in osteoarthritis: the role of COX-2 inhibitors. 924 47

The new class of antiinflammatory and analgesic drugs, the selective cyclooxygenase (COX-2) inhibitors, which promise to be devoid of the types of toxicity associated with nonsteroidal antiinflammatory drugs (NSAID), especially adverse gastrointestinal effects, are under clinical trial but are not yet available for use. All NSAID, including those most recently introduced, exhibit nonselectivity of action, producing therapeutic blood levels that inhibit constitutive COX-1 and deplete tissue protective prostaglandins. Among NSAID, the diclofenac/misoprostol combination (Arthrotec) is unique in possessing an active component, misoprostol, to help prevent NSAID induced gastrointestinal damage. Ulcer damage and associated serious complications probably represent only the tip of the iceberg in relation to clinically significant side effects associated with the use of NSAID. In this context, metaanalysis of 8 large multicenter studies reported here has shown that patients taking NSAID show a mean decrease in hemoglobin over 4 - 12 weeks' assessment, with some 10-20% of patients exhibiting clinically significant decreases (> or = 1 g/dl) early in treatment. Patients taking diclofenac/misoprostol showed significantly less of a decline in hemoglobin and up to 50% fewer clinically significant decreases than patients receiving diclofenac alone. The misoprostol component of diclofenac/misoprostol may also help to restore homeostasis in tissues other than the gut. Inhibition of the activity or release of various tissue damaging agents and inflammatory cytokines, e.g., thromboxane and interleukin 1, are described, as are in vivo animal studies that have revealed synergistic or potentiating analgesic and antiinflammatory activities between misoprostol and NSAID, particularly diclofenac. Clinical studies in postsurgical dental pain in more than 500 patients have now shown enhanced analgesia, with greater relief over a longer period, for the diclofenac/misoprostol combination compared with diclofenac alone. The relevance of these findings to pain and inflammation control in arthritis is discussed. Enhanced control of morning stiffness provided by diclofenac/misoprostol, possibly also the result of misoprostol/diclofenac synergy, is also reported, and the development of an objective system that measures 24 hour ambulatory activity is described. Using this Numact recorder, improved mobility in patients receiving diclofenac 75 mg/misoprostol 200 microg was observed compared with patients treated with diclofenac 75 mg slow release. Further studies are being performed employing magnetic resonance imaging both to assess antiinflammatory effects in joint soft tissue architecture and to assess whether the synergistic stimulatory effects of diclofenac and misoprostol on human osteoarthritic cartilage that have been reported in vitro are clinically evident. A growing body of evidence supports the view that the diclofenac/misoprostol combination provides an improved therapeutic ratio over diclofenac alone, not only by improving gastrointestinal safety but also by enhancing analgesic/antiinflammatory effects.
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PMID:Diclofenac/misoprostol: novel findings and their clinical potential. 959 52

Cyclooxygenase (COX), first purified in 1976 and cloned in 1988, is the key enzyme in the synthesis of prostaglandins (PGs) from arachidonic acid. In 1991, several laboratories identified a product from a second gene with COX activity and called it COX-2. However, COX-2 was inducible, and the inducing stimuli included pro-inflammatory cytokines and growth factors, implying a role for COX-2 in both inflammation and control of cell growth. The two isoforms of COX are almost identical in structure but have important differences in substrate and inhibitor selectivity and in their intracellular locations. Protective PGs, which preserve the integrity of the stomach lining and maintain normal renal function in a compromised kidney, are synthesized by COX-1. In addition to the induction of COX-2 in inflammatory lesions, it is present constitutively in the brain and spinal cord, where it may be involved in nerve transmission, particularly that for pain and fever. PGs made by COX-2 are also important in ovulation and in the birth process. The discovery of COX-2 has made possible the design of drugs that reduce inflammation without removing the protective PGs in the stomach and kidney made by COX-1. These highly selective COX-2 inhibitors may not only be anti-inflammatory but may also be active in colon cancer and Alzheimer's disease.
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PMID:Cyclooxygenases 1 and 2. 959 50

The enzymes cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) catalyze the conversion of arachidonic acid to prostaglandin (PG) H2, the precursor of PGs and thromboxane. These lipid mediators play important roles in inflammation and pain and in normal physiological functions. While there are abundant data indicating that the inducible isoform, COX-2, is important in inflammation and pain, the constitutively expressed isoform, COX-1, has also been suggested to play a role in inflammatory processes. To address the latter question pharmacologically, we used a highly selective COX-1 inhibitor, SC-560 (COX-1 IC50 = 0.009 microM; COX-2 IC50 = 6.3 microM). SC-560 inhibited COX-1-derived platelet thromboxane B2, gastric PGE2, and dermal PGE2 production, indicating that it was orally active, but did not inhibit COX-2-derived PGs in the lipopolysaccharide-induced rat air pouch. Therapeutic or prophylactic administration of SC-560 in the rat carrageenan footpad model did not affect acute inflammation or hyperalgesia at doses that markedly inhibited in vivo COX-1 activity. By contrast, celecoxib, a selective COX-2 inhibitor, was anti-inflammatory and analgesic in this model. Paradoxically, both SC-560 and celecoxib reduced paw PGs to equivalent levels. Increased levels of PGs were found in the cerebrospinal fluid after carrageenan injection and were markedly reduced by celecoxib, but were not affected by SC-560. These results suggest that, in addition to the role of peripherally produced PGs, there is a critical, centrally mediated neurological component to inflammatory pain that is mediated at least in part by COX-2.
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PMID:Pharmacological analysis of cyclooxygenase-1 in inflammation. 978 85


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