Hydroxyurea, an agent now commonly used to decrease the number of vaso-occlusive pain crises in patients with sickle cell disease, interferes with DNA synthesis, causing macrocytosis by which compliance with therapy may be monitored.

Can hydroxyurea cause macrocytic anemia?

macrocytosis is a common, and expected, side effect of hydroxyurea therapy in human patients. In fact, monitoring of peripheral macrocytosis has been used to assess adherence to treatment with hydroxyurea in human patients with sickle cell anemia.

What does hydroxyurea do to MCV?

Hydroxyurea is used in the treatment of sickle cell anemia and beta-thalassemia major to increase the content of hemoglobin F (HbF) and presumably ameliorate clinical symptoms. Under therapy with hydroxyurea an increase of the mean corpuscular volume (MCV) of the erythrocytes can be observed.