Effects on cyclooxygenase

The answer is d. (Katzung, p 605.) Celocoxib is a eyelooxygenasell inhibitor. Aspirin, ibuprofen, and piroxicam are relatively no ns elective inhibitors of cyclooxygenases. Acetaminophen has no effect on cyclooxygenases. 

Noreen, Y., Two new isoflavones from Ceiba pentandra and their effect on cyclooxygenase-catalyzed prostaglandin biosynthesis, Journal of Natural Products, 61, 8, 1998. 

Acetaminophen [a seat a MIN oh fen] and phenacetin [fe NASS e tin] act by inhibiting prostaglandin synthesis in the CNS. This explains their antipyretic and analgesic properties. They have less effect on cyclooxygenase in peripheral tissues, which accounts for their weak anti-inflammatory activity. Acetaminophen and phenacetin do not affect platelet function or increase blood clotting time, and they lack many of the side-effects of aspirin. [Note Phenacetin can no longer be prescribed in the United States because of its potential for renal toxicity. However, it is present in some proprietary preparations.]... 

Hosoda A, Ozaki Y, Kashiwada A, Mutoh M, Wakabayashi K, Mizuno K, Nomura E, Taniguchi H (2002) Syntheses of ferulic acid derivatives and their suppressive effects on cyclooxygenase-2 promoter activity. Bioorg Med Chem 10 1189... 

Like aspirin, ibuprofen is a nonsteroidal anti-inflammatory drug. It is a cyclooxygenase inhibitor that interferes with COX-1 and COX-2 forms of that enzyme. Its effects on COX-2 give it fever-reducing (antipyretic), analgesic (pain relief), and anti-inflammatory functions. 

Sulfinpyrazone is used in medicine as a nonsteroid anti-inflammatory, fever-reducing analgesic however, it is believed, that it inhibits cyclooxygenase of thrombocytes. In addition, it is also possible that its action is also linked with the action on membrane of thrombocytes and reduced quantities of secreted adenosine diphosphate and serotonin, which facilitate thrombocyte aggregation. Unlike aspirin, it has no effect on those who do not have irregular aggregation systems. 

Zhang J, Ding EL, Song Y. Adverse effects of cyclooxygenase 2 inhibitors on renal and arrhythmia events. Meta-analysis of randomised trials. J Am Med Ass 2006 296 1619-32. 

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