Metronidazole and transient leukopenia.

To the Editor:— Lefebvre and Hesseltine (194:15, 1965) reported a 1% incidence of transient leukopenia and neutropenia in 386 patients treated up to 14 days with metronidazole forTrichomonas vaginalisinfections. Such findings may be less alarming than implied. While it was not the primary purpose of the writer's study to statistically analyze hematopoietic effects of the agent, over 2,000 complete blood counts and 9 bone-marrow biopsies have been done in 605 treated patients with metabolic, endocrine, or autoimmune disorders. Comparable amounts of the drug were used, but for more prolonged periods than in the above study. Twelve subjects, whose white blood cell counts ( WBCs) and peripheral smears were normal prior to therapy, showed the same transient leukopenia and neutropenia described by Lefebvre and Hesseltine. However, the circulating elements spontaneously returned to normal after the 14th day of treatment, and remained so in every case. At the same time