Anti-inflammatory action of erythromycin. Its inhibitory effect on neutrophil NADPH oxidase activity.

The effects of erythromycin on the NADPH oxidase activity in the neutrophils of normal subjects and patients with bronchiolitis were investigated. In the patients receiving erythromycin, NADPH oxidase activity was significantly lower in a whole-cell system than that before therapy. Erythromycin was also found to inhibit the superoxide generation of neutrophils exposed to phorbol myristate acetate in a whole-cell system and the activation of superoxide-generating NADPH oxidase by sodium lauryl sulfate (sodium dodecyl sulfate) in a cell-free system. The concentration of the drug required for 50 percent inhibition of the oxidase was 0.7 mM in the whole-cell system and 0.2 mM in the cell-free system. These results suggest that erythromycin, an antibiotic which penetrates well into human neutrophils, may exhibit an anti-inflammatory action due to inhibiting of neutrophil NADPH oxidase activation.