Diclofenac inhibits monocyte superoxide production ex vivo in rheumatoid arthritis.

Effects of the nonsteroidal anti-inflammatory drug, diclofenac, on stimulated monocyte superoxide production were assessed directly in vitro and following treatment of patients with rheumatoid arthritis ex vivo. Diclofenac inhibited superoxide generation provoked by serum treated zymosan (STZ) and fluoride anion (F) but not by phorbol myristate acetate (PMA) in vitro. Following patient therapy, inhibition of superoxide production occurred when STZ and PMA, but not F were used as stimuli. No changes were seen in control subjects. The contrasting profiles of inhibition seen in vitro and ex vivo suggest an indirect effect on superoxide production during clinical use of the agent. These data are consistent with the hypothesis that anti-inflammatory drugs may act in rheumatoid arthritis by inhibiting phagocyte superoxide anion production.