The significance of inhibition of prostaglandin synthesis in the selection of non-steroidal anti-inflammatory agents.

A statistically significant correlation can be shown to exist between the concentrations in which established non-steroidal anti-inflammatory agents inhibit prostaglandin synthesis in vitro and the doses in which they exert anti-inflammatory and antipyretic effects in animals. With regard to their antinociceptive activity, this relation is less distinct. Derivatives of clinically effective non-steroidal anti-inflammatory agents can interfere with prostaglandin synthesis in vitro without displaying any activity in vivo. Moreover, the capacity to inhibit this enzyme system is not a property exclusive to non-steroidal anti-inflammatory agents; tricyclic psychotropic drugs exert a similar action. The fact that a substance affects prostaglandin synthetase in vitro is consequently not a reliable indication that it possesses anti-inflammatory properties. On the other hand, the demonstration of effects of this type is important in elucidating the mechanism of action of a drug.