Carbamazepine. What physicians should know about its hematologic effects.

Transient leukopenia and, less commonly, neutropenia may occur with carbamazepine therapy. Discontinuation of therapy is usually not indicated unless symptoms are severe, persistent, or accompanied by infection. Patients with a low leukocyte or neutrophil count before treatment may be at increased risk for carbamazepine-induced leukopenia or neutropenia. Careful monitoring of blood counts, particularly during the first month of therapy, is essential. The frequency of monitoring can be determined on an individual basis. If a hematologic abnormality develops, the frequency of monitoring should be increased, especially if carbamazepine is not discontinued. Only when the neutrophil count falls below 500/mm3 does a severe risk of infection exist.