Lamotrigine is an antiepileptic drug of the phenyltriazine class with inhibitory effects on voltage-sensitive sodium channels, leading to an inhibition in the release of glutamate and resulting in a general inhibitory effect on cortical neuronal function. Lamotrigine is also a weak dihydrofolate reductase inhibitor. The drug is approved by the U.S. Food and Drug Administration for maintenance treatment of bipolar type I disorder in adults. There have been reports of hematologic adverse effects with lamotrigine therapy. This case report describes a 16-year-old female who developed profound anemia while on lamotrigine therapy.

Ms. X was a 16-year-old African-American female with sickle cell trait and mood disorder referred by the Division of Youth Services (DYS). Her medication regimen included lamotrigine 200 mg in the morning, aripiprazole 5 mg in the morning, and mixed amphetamine salts extended-release 30 mg in the morning. While at DYS, she developed fatigue and headaches with exertion. Her blood work detected a very low hemoglobin level of 3.1 g/dL and a very low hematocrit of 10.9%. Her MCV, MCH, and MCHC were within the normal range. The remainder of her blood count and other labs were within normal limits. The patient’s blood pressure was 105/70 mm Hg and her pulse was 109. The patient was sent to the local emergency room immediately; upon hospital admission, she received 4 units of packed red blood cells via transfusion.

After a blood transfusion, the patient’s hemoglobin level improved to 9.7 g/dL. The patient’s symptoms had improved significantly; her headaches and fatigue with exertion were gone. It was suspected that her profound anemia was induced by lamotrigine. She was discharged from the hospital with instructions to stop lamotrigine and visit a hematology specialist. Several weeks later, she underwent a hematologic evaluation, including a bone marrow biopsy and genetic testing, which were unremarkable. Her hemoglobin level remained stable.

The patient’s anemia resolved after the discontinuation of lamotrigine. The patient was followed for 1 year with blood work performed every few months. Her hemoglobin level did not drop further and in fact slowly increased to 13.9 g/dL spontaneously over the next year. In the literature, there have been reports of blood dyscrasias that may or may not be associated with hypersensitivity syndrome in patients who take lamotrigine. Considering hematologic adverse effects, it may be prudent to consider a baseline blood count before starting lamotrigine and repeat this test 3 to 6 months after initiation. It remains unclear whether lamotrigine use with a background of sickle cell trait in this patient put her at an increased risk of profound anemia. Further studies are required to explore the effects of this commonly used medicine.

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