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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Production of prostaglandins is a critical step in transducing immune stimuli into central nervous system (CNS) responses, but the cellular source of prostaglandins responsible for CNS signalling is unknown. Cyclooxygenase catalyzes the rate-limiting step in the synthesis of prostaglandins and exists in two isoforms. Regulation of the inducible isoform, cyclooxygenase 2, is thought to play a key role in the brain's response to acute inflammatory stimuli. In this paper, we report that intravenous lipopolysaccharide (LPS or endotoxin) induces cyclooxygenase 2-like immunoreactivity in cells closely associated with brain blood vessels and in cells in the meninges. Neuronal staining was not noticeably altered or induced in any brain region by endotoxin challenge. Furthermore, many of the cells also were stained with a perivascular microglial/macrophage-specific antibody, indicating that intravenous LPS induces cyclooxygenase in perivascular microglia along blood vessels and in meningeal macrophages at the edge of the brain. These findings suggest that perivascular microglia and meningeal macrophages throughout the brain may be the cellular source of prostaglandins following systemic immune challenge. We hypothesize that distinct components of the CNS response to immune system activation may be mediated by prostaglandins produced at specific intracranial sites such as the preoptic area (altered sleep and thermoregulation), medulla (adrenal corticosteroid response), and cerebral cortex (headache and encephalopathy).
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PMID:Intravenous lipopolysaccharide induces cyclooxygenase 2-like immunoreactivity in rat brain perivascular microglia and meningeal macrophages. 913 Jun 63

The purpose of this paper is to review the rationale for a new class of nonsteroidal anti-inflammatory drugs (NSAIDs) known as selective cyclooxygenase (COX)-2 inhibitors and to present preliminary clinical data on 2 COX-2 inhibitors that are approved for use in the United States. The primary mechanism of NSAIDs in the treatment of inflammation is the inhibition of COX, which exists in 2 forms. COX-I appears to regulate many normal physiologic functions, and COX-2 mediates the inflammatory response. Theoretically, an NSAID that inhibits COX-2 selectively should decrease inflammation but not influence normal physiologic functions and thus should cause fewer gastrointestinal side effects. Preliminary data suggest that celecoxib, a highly selective COX-2 inhibitor, is superior to placebo and similar to traditional NSAIDs in the short-term treatment of pain due to osteoarthritis, although it has been associated with adverse effects such as headache, change in bowel habits, abdominal discomfort, and dizziness. Celecoxib also has been shown to be as effective as traditional NSAIDs in the treatment of rheumatoid arthritis, but it may cause fewer adverse effects, including endoscopically documented ulcers. Celecoxib is metabolized in the liver by the cytochrome P-450 isozyme CYP2C9, and thus serious drug interactions are possible. In the treatment of osteoarthritis, rofecoxib has been shown to be as effective as traditional NSAIDs and may cause fewer endoscopically documented ulcers, but its complete adverse-effect profile is not known. Until the selective COX-2 inhibitors are widely used and more clinical as well as pharmacoeconomic studies are published, the exact role of COX-2 therapy cannot be determined. words: cyclooxygenase, celecoxib, rofecoxib, rheumatoid arthritis, osteoarthritis.
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PMID:Selective cyclooxygenase-2 inhibitors for the treatment of arthritis. 1046 13

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs, despite their well-established association with gastroduodenal injury. Recent discovery of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2 has improved our knowledge of the action of NSAIDs. COX-1 is continuously expressed in almost all tissues, where it converts arachidonate to the prostaglandins (PGs) important in homeostatic function; COX-2 is present in immune cells, blood vessel endothelial cells, and synovial fibroblasts. Classic NSAIDs inhibit both COX isoenzymes by occupying the cyclooxygenase-active site, preventing access by arachidonic acid. In theory, a drug such as celecoxib that selectively inhibited COX-2 might block inflammation, pain, and fever while reducing the side effects (gastric erosions and ulcers) associated with inhibition of COX-1. In animal models of inflammation and pain, celecoxib has shown marked suppression of PG production and inflammation compared with indomethacin, the standard COX-1/COX-2 inhibitor. In clinical trials, celecoxib dosed at 100, 200, and 400 mg BID was found to significantly reduce the signs and symptoms of rheumatoid arthritis (RA) and osteoarthritis. In one RA study, celecoxib was found to be as clinically effective as diclofenac after 24 weeks of treatment; at the end of the study, gastroduodenal ulcers occurred significantly more frequently in the diclofenac group (15%) than in the celecoxib group (4%). In a 1-week endoscopy study comparing celecoxib with naproxen and placebo, the incidence of gastric erosions/ulcers was significantly greater in the naproxen group than in the celecoxib or placebo group. The most common adverse effects of celecoxib in clinical studies were headache, diarrhea, abdominal discomfort, and dizziness. Celecoxib has shown significant equivalent anti-inflammatory and analgesic efficacy and has produced less endoscopically apparent gastrointestinal (GI) ulceration or erosion than have 3 classic NSAIDs. Whether it will have long-term GI adverse effects or interact with other medications to cause serious adverse responses (eg, increased GI bleeding or rash in conjunction with other sulfonamide-like drugs) is unknown and remains to be established.
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PMID:Celecoxib, a selective cyclooxygenase-2 inhibitor for the treatment of rheumatoid arthritis and osteoarthritis. 1050 45

Headache is known to be the predominant symptom in acute mountain sickness which is also frequently accompanied by nausea, vomiting and insomnia. Nowadays, every year millions of skiers and mountaineers are attracted to mountains all over the world. At altitudes between 2500 m and 5000 m about 20% to 90% of those who are not adapted to high altitude will experience high altitude headache (HAH). It is well documented that HAH can be best prevented by observance of the golden rule: not to go too high too fast. Although many mountaineers are aware of this rule, its observance is complicated by unknown individual susceptibility, the location of mountain huts, the use of cable cars, limited holiday time, unfavorable weather or avalanche conditions. Therefore, there is a widespread use of drugs for the treatment and prevention of HAH. In the past, the increase in cerebral blood flow during acute hypoxia was thought to be the main cause of HAH. More recent findings, however, have caused this hypothesis to be reduced in importance and have supported the pathogenetic consequence of sensitization of intracranial pain-sensitive structures. The effectiveness of cyclooxygenase inhibition for the treatment and prevention of HAH suggests that especially prostaglandins may be an important mediator between hypoxia and HAH. Besides oxygen, acetazolamide, dexamethasone and especially inhibitors of prostaglandin synthesis such as ibuprofen and naproxen are approved for the treatment of HAH. Acetazolamide, dexamethasone, and aspirin were also found to prevent HAH. The most beneficial effects however, may be achieved by the combined application of acetazolamide and aspirin. This combination increases oxygenation and reduces prostaglandin synthesis.
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PMID:[High altitude headache: epidemiology, pathophysiology, therapy and prophylaxis]. 1058 87

Many reports indicate that nitric oxide (NO) could be involved in migraine without aura (MWA), an extremely diffuse clinical event. Since monocyte may be a relevant source of NO, we analysed monocyte activation in MWA patients, in a period in which they were free of symptoms. NO basal production by MWA peripheral monocytes was significantly higher than in healthy subjects (91.25+/-8.6 microM/10(6) cells vs. 22.6+/-3.2 microM/106 cells). Interestingly, even the release of prostaglandin E2 (PGE2), was higher in MWA patients than in healthy subjects (3137+/-320 pg/10(6) cells vs. 1531+/-220 pg/10(6) cells). The incubation of monocytes from healthy subjects and MWA patients with N-nitro-L-arginine methyl ester caused a marked decrease of both NO and PGE2 release. We hypothesise that NOS and cyclooxygenase pathways in monocytes are linked and are, in MWA patients, up-regulated, even in a symptoms-free period. NO and PGE2 hyperproduction could therefore be involved in the neurovascular modifications leading to migraine attacks.
Cephalalgia 2000 Mar
PMID:Linked activation of nitric oxide synthase and cyclooxygenase in peripheral monocytes of asymptomatic migraine without aura patients. 1096 65

Nonsteroidal anti-inflammatory drugs (NSAIDs), which are used widely to manage pain, are known to inhibit cyclooxygenase, but details of the mechanisms of NSAID action remain unclear. We investigated the ability of three NSAIDs (indomethacin, loxoprofen, and etodolac) to eliminate and inhibit free radicals. Superoxide scavenging activity of these NSAIDs was measured in vitro by electron spin resonance spectrometry using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as a spin trap. Electron spin resonance demonstrated that formation of superoxide-DMPO spin adduct was completely inhibited by two nonselective cyclooxygenase inhibitors, indomethacin (3 mmol) and loxoprofen (3 mmol). The electron spin resonance study also demonstrated that the formation of superoxide-DMPO spin adduct was strongly inhibited by a selective cyclooxygenase-2 inhibitor, etodolac, in a concentration-dependent manner. These results indicate that NSAIDs, including indomethacin, loxoprofen, and etodolac, have direct superoxide scavenging activity.
Headache 2001 Feb
PMID:Direct superoxide scavenging activity of nonsteroidal anti-inflammatory drugs: determination by electron spin resonance using the spin trap method. 1125 97

Paracetamol (acetaminophen) is one of the most widely used of all drugs, with a wealth of experience clearly establishing it as the standard antipyretic and analgesic for mild to moderate pain states. First used clinically by von Mering in 1893, paracetamol did not appear commercially until 1950 in the United States and 1956 in Australia. During the 1960s and 1970s, increasing concern was raised about the toxicity of nonprescription analgesics, but in normal use paracetamol exhibited a consistent safety profile. Its exemplary safety record was marred by the discovery in 1966 that a major overdose could be complicated by severe and sometimes fatal liver damage. Fortunately, early treatment with N-acetylcysteine prevents liver toxicity. A turning point in the choice of pediatric analgesic came in the 1980s when aspirin was linked to Reye's syndrome. As a consequence, paracetamol became the mainstay analgesic and antipyretic for children with a subsequent reduction in the incidence of Reye's syndrome. Currently, paracetamol is a first-line choice for pain management and antipyresis in a variety of patients, including children, pregnant women, the elderly, those with osteoarthritis, simple headaches, and those with noninflammatory musculoskeletal conditions. With proper use, paracetamol seldom causes adverse events and reports of serious side effects are rare. It has a broad tolerability and is of particular value in the treatment of patients in whom nonsteroidal anti-inflammatory drugs are contraindicated such as aspirin-sensitive asthmatics and people at risk of gastrointestinal complications. In the future, a better insight into the mechanism of action of paracetamol may be gained from a fuller understanding of the cyclooxygenase enzymes. In the meantime, paracetamol may find applications in other therapeutic areas, such as the prevention of atherosclerosis via a potential antioxidant activity. In summary, although it is more than a century since the first clinical use of paracetamol, it continues to be a first-line therapy of choice in adults and children with fever and pain. In addition, current research suggests that paracetamol may have a much broader clinical utility in years to come.
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PMID:Paracetamol: past, present, and future. 1131 82

Nonsteroidal anti-inflammatory drugs (NSAIDs) are nonselective inhibitors of cyclooxygenase (COX) isoforms COX-1 and COX-2. NSAIDs have analgesic and anti-inflammatory properties that are proven, and they are extensively used in the treatment of arthritis, pain, and headache. Despite their good efficacy, NSAIDs are associated with significant gastrointestinal (GI) toxicity, which appears to be related to the inhibition of the cytoprotective function of COX-1. Thus, selective COX-2 inhibitors, or coxibs, were designed to inhibit only the production of COX-2-dependent inflammatory prostaglandins, without any effect on COX-1 and its gastroprotective function. This article reviews important evidence on the GI safety of coxibs. Endoscopic studies demonstrated that coxibs, such as celecoxib and rofecoxib, induced significantly fewer ulcers than nonspecific NSAIDs. To analyze whether the incidence of clinical GI events is also lower with coxibs, 2 large controlled clinical trials, the Celecoxib Long-term Arthritis Safety Study (CLASS) and Vioxx Gastrointestinal Outcomes Research (VIGOR), evaluated the GI safety of celecoxib and rofecoxib, respectively. Based on evidence from the VIGOR trial, it was demonstrated that rofecoxib has already fulfilled the promise and significantly decreases the risk of clinically important and complicated GI events compared with a nonselective NSAID, naproxen. In contrast, the CLASS trial showed that the incidence of ulcer complications in patients treated with celecoxib was similar in patients treated with nonspecific NSAIDs.
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PMID:An evidence-based evaluation of the gastrointestinal safety of coxibs. 1190 55

This study addresses possible interactions of the vasodilators nitric oxide (NO), calcitonin gene-related peptide (CGRP) and prostaglandins, which may be implicated in the generation of vascular headaches. Local application of the NO donator diethylamine-NONOate (NONOate) to the exposed dura mater encephali of the rat caused dose-dependent increases in meningeal blood flow recorded by laser Doppler flowmetry. Pre-application of the CGRP receptor antagonist CGRP8-37 significantly attenuated the evoked blood flow increases, while the cyclooxygenase inhibitors acetylsalicylic acid and metamizol were only marginally effective. Stimulation of rat dura mater with NONOate in vitro caused increases in CGRP release. NADPH-diaphorase activity indicating NO production was restricted to the endothelium of dural arterial vessels. We conclude that increases in meningeal blood flow caused by NO depend partly on the release and vasodilatory action of CGRP from dural afferents, while prostaglandins are not significantly involved.
Cephalalgia 2002 Apr
PMID:Increase in meningeal blood flow by nitric oxide--interaction with calcitonin gene-related peptide receptor and prostaglandin synthesis inhibition. 1204 64

Nearly 80% of patients with systemic lupus erythematosus (SLE) are treated with NSAIDs for fever, arthritis, serositis and headaches. This article reviews currently available literature on non-selective and selective inhibitors of cyclooxygenases, with an emphasis on the efficacy and safety profile reported in SLE patients. All NSAIDs, regardless of their cyclooxygenase selectivity, induced renal side effects including sodium retention and reduction in glomerular filtration rate. In addition, lupus nephritis is a risk factor for NSAID-induced acute renal failure. NSAID-induced hepatotoxicity is increased in SLE patients in addition to cutaneous and allergic reactions. Finally, aseptic meningitis has been reported more frequently in NSAID-treated SLE patients. Nevertheless, NSAIDs can safely be prescribed to most lupus patients provided that their administration is re-evaluated on a regular basis and the patient is closely monitored.
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PMID:Risk:benefit ratio of nonsteroidal anti-inflammatory drugs in systemic lupus erythematosus. 1526 45


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