Bone marrow culture in patients treated with Ticlopidine

Bone marrow cells obtained from 15 patients treated with Ticlopidine (500 mg/day) for a month, and from 20 matched controls were cultured in agar. GM colonies and clusters were counted after 7 and 14 days of culture. CFU GM were slightly decreased in the patients treated by Ticlopidine. In 8 patients, in which the bone marrow was cultured on a second occasion 3 months latter, a slight increase in the inhibition of CFU GM was observed. It could be due to the mechanism of action of the drug (by an increased synthesis of PGE1) and not to a toxic side effect. The few cases of reversible agranulocytosis reported in the literature might be due to the inhibition of myelopoiesis in patients with medullary reserves already impaired.