Regulation of prostaglandin synthesis by antiinflammatory drugs.

The prostaglandins (PG), thromboxanes, and leukotrienes (LT) are potent groups of mediators derived from arachidonic acid. The functions of these compounds are numerous and involve every organ system, but their roles in physiology and pathology are not completely understood. PG and LT are important mediators of inflammatory reactions. Convincing evidence supports the hypothesis than inhibition of PG synthesis accounts for both the major therapeutic antiinflammatory and toxic side effects of the nonsteroidal antiinflammatory drugs. New research has revealed that PG are synthesized by 2 forms of the enzyme cyclooxygenase, COX-1 and COX-2. Since COX-1 generally produces PG responsible for cytoprotective functions and COX-2 produces PG in inflammatory reactions, it is a reasonable hypothesis that drugs that are selective inhibitors of COX-2 should be effective antiinflammatory agents with few toxic side effects.