Lamotrigine-induced neutropenia after high-dose concomitant initiation with phenytoin.

Lamotrigine has been repeatedly reported to cause hematologic toxicities, which may be associated with high initial doses or excessive escalation. A 29-year-old lady experienced profound neutropenia after two weeks of lamotrigine high initial dose, started within two days of phenytoin. The too-early dose intensification may have produced lamotrigine-induced blood dyscrasia.