How to replace lamotrigine with valproate

If lamotrigine (LTG) has to be replaced with valproate (VPA), this exchange may be complicated by adverse events that result from the complex interaction of both drugs. We report on two cases in which such problems occurred in spite of a cautious switch considering the VPA induced LTG serum increase. The satisfying outcome after a sudden and complete withdrawal of LTG in both cases encouraged us to perform the switch from LTG to VPA systematically by discontinuing LTG abruptly and building up the VPA maintenance dosage very rapidly in the following five consecutive patients who required this exchange. We recommend our abrupt dosage change-over strategy as an easy, safe and cost-effective option.