Diphenylhydantoin (DPH) is one of the most widely used anticonvulsants for treatment and prevention of seizures. However it is frequently associated with drug-induced leukopenia. Hyper-sensitivity reactions to phenytoin are well recognized and can be severe.
Phenytoin is associated with serious hematologic side effects such as agranulocytosis, thrombo-cytopenia, red cell aplasia and hemolytic anemia, either through humoral or cell-mediated immune mechanism. We describe a 57 -year-old male patient who developed a severe granulocytopenia while taking phenytoin for 66 days in the total amount of 21.6 gram. Bone marrow examination showed Isolated depletion of myeloid elements.
After 10 days of phenytoin withdrawal and G-CSF treatment, the patient recovered from granulocytic suppression. Using in vitro culture, marrow suppression associated with phenytoin therapy was felt to be non-immune mediated marrow suppression.

Keywords: Phenytoin, Leukopenia, Agranulocytosis