Increased Lamotrigine Clearance and Decreased Levels with Non-oral Hormonal Contraceptive Use (P2.5-005)

Objective: To describe the effect of non-oral estrogen containing contraceptive methods on lamotrigine clearance and serum levels in women with epilepsy Background: Previous studies demonstrate that oral hormonal contraceptives increase lamotrigine clearance through glucoronidation. This leads to variable lamotrigine serum concentrations throughout monthly cycles in women on oral contraceptives. The effects of non-oral hormonal contraception on AED pharmacokinetics are less well characterized. Design/Methods: Retrospective review of serum lamotrigine levels drawn from female patients with epilepsy while using a non-oral hormonal contraceptive method (estrogen patch, vaginal ring) compared to off contraception (19 lab draws from 4 patients). Exclusion criteria included pregnancy, Results: Lamotrigine clearance was higher in women while on a non-oral hormonal contraceptive device compared to while off it (p Conclusions: The findings suggest that non-oral hormonal contraceptives increase lamotrigine clearance which leads to low lamotrigine serum levels. This has important implications that lamotrigine levels may fluctuate significantly in women on non-oral hormonal contraceptive during the week off the medication. Disclosure: Dr. King has nothing to disclose. Dr. Gerard has received research support from Sunovion Phramaceuticals.