Granulocytopenia, agranulocytosis, and red-cell hypoplasia and aplasia, and megaloblastic anemia are rarely associated with the use of primidone. Megaloblastic anemia is actually a group of related disorders with different causes that share morphological characteristics—enlarged red blood cells with abnormally high nuclear-cytoplasmic ratios resulting from delayed maturation of nuclei combined with normal maturation of cytoplasm, into abnormal megakaryocytes and sometimes neutrophils; regardless of etiology, all of the megaloblastic anemias involve impaired DNA replication. The anticonvulsant users who get this also tend to eat monotonous diets devoid of fruits and vegetables.