MEGALOBLASTIC ANEMIA DUE TO DILANTIN THERAPY

Abstract

Megaloblastic anemia occurring in an epileptic who had been receiving dilantin therapy is reported. Other possible causes of the anemia were carefully excluded. The serum B12 level was low normal. Following the initial emergency transfusions and the later diagnostic administration of 1000 mg of vitamin B12 during the Schilling test, there was gradual improvement. Within a period of one month all hematological findings were within normal limits. Dilantin sodium, grains 1 1/2, three times a day was maintained: no other medication was given. The occurrence and laboratory findings in previously reported cases as well as the possible mechanisms as to cause was reviewed. The etiology of the megaloblastic anemia induced by antiepileptic drugs seems to be a derangement of folic acid or B12 metabolism and is easily overcome by administering an excess of B12 or folic acid without stopping the offending drugs. The present case and those in the literature point to the importance of periodic blood counts in patients receiving anti-convulsant drugs. Whether prophylactic folic acid should be administered is a moot point as the danger of pernicious anemia as a cause of neurologic complications would be marked. Megaloblastic anemia is a rare complication of anticonvulsant therapy and the anemia does not relapse if the original drugs are continued with the addition of vitamin B12 or folic acid.