Mechanisms of action of disease modifying antirheumatic drugs.

The relationship between the biologic activities of disease modifying antirheumatic drugs (DMARD) and their therapeutic effects are complex. Some DMARD are prodrugs, e.g., azathioprine; others may act in combination with endogenous substances, e.g., D-penicillamine and copper salts. Gold compounds, antimalarials, sulfasalazine, azathioprine and methotrexate affect various phagocytic cell functions. Most DMARD inhibit the immune responses of monocytes and of T and B lymphocytes. Gold, sulfasalazine, D-penicillamine also affect fibroblast and/or endothelial cell proliferation. Many DMARD inhibit responses to, or production of, cytokines. Several DMARD have overlapping biologic effects but differ in their therapeutic efficacy in individual patients for unknown reasons.