Inhibition of human neutrophil chemotaxis in vitro by phenothiazines and related compounds.

Chlorpromazine (CPZ) and three other phenothiazines and the structurally related antidepressant drugs imipramine and amitriptyline were found to depress human neutrophil chemotactic responsiveness. A 7 X 10(-6)M solution of CPZ inhibited chemotaxis, whereas concentrations of the other tested drugs 10 to 1,000 times greater than this were needed to inhibit chemotaxis. This effect of CPZ could not, however, be demonstrated when testing neutrophils from patients treated with the drug. The inhibition of chemotaxis was reversible when CPZ-incubated neutrophils were washed before testing for chemotactic responsiveness. CPZ affects neutrophil funcjtion as well as other aspects of immune response.