Can be used in combination with other medications including lithium (predictable and manageable drug–drug interactions).

Polypharmacy is often required for the management of bipolar disorder; therefore, the ability to combine medications safely is essential. For example, Lithium has a narrow therapeutic index, but can be safely combined with Lamictal, which does not significantly change Lithium serum levels. Lamictal can also be effectively combined with valproate and carbamazepine, provided that recommended dose adjustments are followed.