Most currently used antiepileptic drugs appear to be acceptable during breastfeeding as single agents. Follow-up studies indicate that maternal carbamazepine, lamotrigine, phenytoin, and valproate cause no long-term developmental problems in breastfed infants. Long-term outcomes with other drugs and the many possible drug combinations have not been well studied.
Acute adverse reactions have been reported occasionally with some anticonvulsants. All infants whose mothers take antiepileptic drugs should be monitored for side effects such as rashes, apnea, drowsiness, adequate weight gain, and developmental milestones, especially in younger exclusively breastfed infants and with combinations of antiepileptics. Routine measurement of infant serum levels is generally not necessary, but can be used to rule out toxicity if there is a concern. For detailed information on specific drugs, refer to LactMed: https://www.ncbi.nlm.nih.gov/books/NBK501922/