CYCLOOXYGENASE INHIBITORS

CYCLOOXYGENASE INHIBITORS bind reversibly or irreversibly to the enzyme cyclooxygenase (originally referred to as the prostaglandin synthase system or ‘prostaglandin H2 synthase’; (PGHS)-l and (PGHS)-2). Members of the prostaglandin family have a number of proinflammatory or hyperalgesic actions, and consequently many cyclooxygenase inhibitors are used as anthnflammatories and ANALGESICS. Prostanoids are members of the eicosanoid family of phospholipid mediators, and are comprised of the thromboxanes and the prostaglandins, both of which are formed by the complex cyclooxygenase system. They share common precursors in the form of a series of unstable cyclic endoperoxides. The first stage of the transformation of arachidonic acid has the enzyme endoperoxide synthase oxygenate arachidonate, followed by cyclization to give a cyclic endoperoxide called PGG2. These reactions are inhibited by cyclooxygenase inhibitors. Subsequently, PGG2 is converted by a peroxidase action to PGH2. This is a common precursor for a number of different pathways, forming prostacyclin (by prostacyclin synthase), the various prostaglandins or thromboxanes (by thromboxane synthase). See THROMBOXANE SYNTHASE INHIBITORS. The conversion depends Read more […]

ANTIINFLAMMATORY AGENTS

ANTIINFLAMMATORY AGENTS are drugs that are used to reduce inflammatory responses in the body. Although inflammation is essentially a normal defensive mechanism (a reaction to tissue injury, infection, inhalation of foreign proteins), the manifestations may be so serious and inappropriate or involve such discomfort, that treatment with antiinflammatory agents is required. Inflammatory conditions can be acute (as in insect stings) or chronic (chronic asthma, dermatitis and other skin conditions, rheumatoid conditions). A wide range of drugs may be used to treat one or other inflammatory condition, and potential toxicity in relation to the medical condition is an important determinant of choice. The NSAID ANALGESIC group has the widest antiinflammatory use, and their inhibitory antiinflammatory property is due to their cyclooxygenase activity (see CYCLOOXYGENASE INHIBITORS). Here the associated relief of pain is largely attributable to some degree of correction of the underlying inflammatory condition. Some of this group are relatively non-toxic and are available without prescription for use for relatively trivial complaints, e.g. aspirin and ibuprofen. (Paracetamol has insufficient antiinflammatory action to be useful Read more […]