Modified Atkins diet may reduce serum concentrations of antiepileptic drugs

Background: Modified Atkins diet is a treatment option for patients with pharmacoresistant epilepsy that is not suitable for surgery. In the last few years, we have tried dietary treatment added to antiepileptic drugs (AEDs) in adult patients with severe epilepsy.

Aim of the study: To examine a possible pharmacokinetic interaction between the modified Atkins diet and AEDs.

Methods: In four patients, AED serum concentrations were measured before onset and after 4 and 12 weeks on the diet. The patients used combinations of two or three AEDs, including carbamazepine, clobazam, lamotrigine, nitrazepam, oxcarbazepine, valproate, zonisamide, and topiramate. The patients did not change the type or dose of their AEDs during the diet period.

Results: After 12 weeks on the diet, the average serum concentrations of the respective AEDs were reduced by 35% (range 6-46%) compared to prediet values.

Conclusions: Modified Atkins diet used as add-on therapy to AEDs in four patients with drug resistant seizures caused a considerable decrease in AED serum concentrations. In individual patients, this could be of clinical relevance, and we recommend that AED serum concentrations should be closely monitored when offering this diet to adults with epilepsy.