Let food be thy medicine. The interaction between ketogenic diet therapy and anti-seizure medications: A systematic review.

Ketogenic diet therapy (KDT) is a nonpharmacological treatment that has been demonstrated to be effective in reducing seizures in patients with drug-resistant epilepsy. As the majority of patients on KDT are also receiving anti-seizure medications (ASMs), questions about their combination often arise. KDT is typically implemented as an add-on, and not a substitute for ASMs. Drug monitoring and specific laboratory studies may be helpful in specific cases of cotherapy. Valproate, topiramate, zonisamide, and lamotrigine may be potentially problematic with KDT, but the evidence for this is not conclusive. ASM reduction is usually attempted after 1 month of KDT if a child is showing seizure reduction (but weaning ASMs does not require seizure freedom). Failure to wean an ASM does not mean KDT has failed and adding a new ASM may be beneficial in those cases after several months of KDT fine-tuning. The purpose of this review was to discuss the evidence for possible negative (or positive) pharmacodynamic interactions between KDT and ASMs. In addition, practical suggestions for the weaning or adding of ASMs in patients on KDT are provided.