Effects of ondansetron, granisetron, ramosetron, and azasetron on human neutrophil functions

Neutrophil functions play an important role in the antibacterial or antitumor host defense system. Ondansetron, granisetron, ramosetron, and azasetron are often used in gynecological patients as a prophylaxis against postoperative emesis or chemotherapy-induced emesis. In this study, using an ex vivo system, we have shown that these antiemetics at clinically relevant concentrations had no effect on superoxide (O₂^-) and hydrogen peroxide (H₂O₂) production of neutrophils, although high doses of these drugs significantly inhibited it to a similar degree. The drugs failed to impair chemotaxis or phagocytosis and to scavenge O₂^- or H₂O₂generated by an acellular system. Inhibition of the reactive oxygen species production may be due to attenuation of calcium elevation in neutrophils with these antiemetics. Our findings suggest that we are able to use these antiemetics in gynecological patients with cancer or those undergoing surgery without great caution.