Hematological safeguards during treatment with the phenothiazine derivatives.

Abstract

Agranulocytosis followed the administration of chlorpromazine in 18 patients undergoing therapy for mental illness. The total cumulative dose that induced this reaction ranged from 2 to 112 Gm., with an average of 20 Gm. The time required for leukopenia to develop ranged from 10 to 400 days, but in most cases it was recognized after 20 to 45 days of therapy. It was found in highest incidence in women and only in Caucasian patients. During prolonged periods of treatment with this drug it was impossible to predict when a sudden drop in the leukocyte count would occur. When phenothiazine derivatives are used in treating chronic mental illnesses, it is considered essential that weekly leukocyte counts be made, especially between the 2nd and 10th week of treatment; that monthly counts be made thereafter as long as the patient continues to receive the drug; and that observers be instructed to report promptly all instances of sore throat, stomatitis, fever, malaise, chills, or other evidences of infection.