fayerody - Your doctor is correct, as Depakote (Elavil-CDN - divalproex) increases blood levels of Lamictal (lamotrigine) by 200%. This is due to Depakote decreasing the clearance (elimination from the body) of Lamictal. I am not absolutely sure of the mechanism underlying this effect, and I couldn't find a reasonable explanation in the literature. The decrease in clearance of the Lamictal causes it to build up in the bloodstream. This, in effect, increases the half-life (the amount of time it takes for half of an ingested dose of a drug to be inactivated &/or excreted from the body) of Lamictal from approximately 25 hours to 50 hours.

Sorry that I cannot be more specific on the mechanism of action, but the doubling of half-life of Lamictal by Depakote is well documented. - Cam