Inhibition of neutrophil activation by nonsteroidal anti-inflammatory drugs.

Nonsteroidal anti-inflammatory drugs are thought to prevent inflammation in rheumatoid arthritis by inhibiting prostaglandin synthesis. This observation does not explain, however, why nonsteroidal anti-inflammatory drugs are able to control inflammation caused by other mediators. To determine whether nonsteroidal anti-inflammatory drugs also exert an effect on neutrophil activation, in vitro and in vivo studies were undertaken. Aggregation, superoxide anion generation, and lysosomal enzyme release were assessed. The nonsteroidal anti-inflammatory drugs were found to inhibit these neutrophil responses, but the patterns of inhibition varied from drug to drug. These findings suggest that nonsteroidal anti-inflammatory drugs may have direct effects on neutrophil activation that are independent of their shared inhibition of prostaglandin synthesis.