Enzyme cyclo-oxygenase

Indometacin, which is a non-steroidal anti-inflammatory drug, inhibits the enzyme cyclo-oxygenase implicated in inflammatory reactions. Indometacin is more effective as an anti-inflammatory agent than ibuprofen and tends to have a higher side-effect profile, including headache, diarrhoea and gastrointestinal disturbances. Rectal administration reduces but does not prevent gastrointestinal tract disturbances. 

NSAIDs exert their therapeutic action by blocking the enzyme cyclo oxygenase, which prevents the formation of prostaglandins from arachidonic acid, produced when tissue is damaged prostaglandins are major contributors... 

All compounds inhibit the enzyme cyclo-oxygenase (COX), but show significant differences in the pharmacological profiles. Most of the compounds are inhibitors of both known COX co-enzymes, though only some drugs show selectivity towards the COX-2 enzyme (i.e., 15, 16, 17, 19, 20). 

Aspirin reduces platelet aggregation by inhibiting the enzyme cyclo-oxygenase, which is necessary for the formation of thromboxane A2. Its use is recommended prophylactically in patients with heart disease such as angina and arrhythmia as well as those with previous thrombotic disease. 

Both of these effects are due to the inhibition of an enzyme, cyclo-oxygenase (COX). This enzyme normally converts arachidonic acid to prostaglandins, thromboxanes and prostacyclin. (See Figure 7.1.)... 

NSAIDs exert their effects by inhibition of the enzyme cyclo-oxygenase (COX). This results in reduced production of prostaglandins and thromboxanes because COX normally catalyses their formation from arachidonic acid. Prostaglandins play a role in pain by sensitising sensory nerve endings to the effects of other mediators such as bradykinin. 

Aspirin, or acetylsalicylic acid, has been used for more than 100 years for its analgesic, antipyretic and anti-inflammatory activities. More recently an array of NSAIDs have been developed and introduced into the clinic. For the most part these drugs are well tolerated, but a variety of Type A ADRs, some of which can be life threatening, have been reported for these drugs. An important mechanism of action of the NSAIDs efS-cacy is the inhibition of the enzyme cyclo-oxygenase 2 (COX-2), which prevents the overproduction of prostaglandins and decreases the pain, fever, and inflammation associated with COX-2 activity. 

The reactions in Scheme 1.2 are enzyme-mediated. The conversion of arachidonic acid to PGG2 is controlled by the enzyme cyclo-oxygenase. This reaction starts by removal of the pro-5 hydrogen at C-13 and the oxygen atoms subsequently attached at C-9 and C-11 come from the same oxygen molecule. A second molecule enters into the hydroperoxide at C-15. The reaction is inhibited by non-steroidal anti-inflammatory agents such as aspirin and also by several acetylenic fatty acids. 

The role of the inducible enzymes cyclo-oxygenase-2, nitric oxide synthase and heme oxygenase in angiogenesis of... 

Unfortunately, frequent exposure to NSAIDS may also cause two detrimental effects. These agents inhibit the activity of cyclo-oxygenase, an important enzyme in synthesis of gastroprotec-tive prostaglandins. More importantly, NSAIDS may cause breaks... 

The synthesis of eicosanoids begins with arachidonic acid (C20 4 n-6 fatty acid) which is component part of cell membranes. The synthetic pathway is outlined in Figure 4.8. A key enzyme in this process is cyclo-oxygenase (COX) which occurs in two... 

Naproxen, a non-steroidal anti-inflammatory drug, inhibits prostaglandin release through inhibition of the cyclo-oxygenase-2 enzyme, producing an analgesic and anti-inflammatory effect. 

Renal clearance is usually decreased. Renal blood flow in particular is often poised critically and the use of, for example, a non-steroidal anti-inflammatory drug may cause heart failure and/or renal failure in people with existing cardiac conditions or some preexisting degree of chronic renal failure. These non-selective inhibitors of the cyclo-oxygenase enzyme... 

Aspirin acts by interfering with the synthesis of prostaglandins, which are connected to the causes of inflammation and fever. In particular it is an inhibitor of the cyclo-oxygenase (Cox-2) enzyme. Studies of the use of aspirin as an anticlotting agent suggest that half an aspirin tablet per day may reduce the risk of heart attack and stroke in some people.3... 

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