How the interaction occurs:
Lamotrigine increases how quickly your body processes levonorgestrel-only or norethindrone-only contraceptives.
What might happen:
The amount of the contraceptive in your blood may decrease, so it may not work as well at preventing pregnancy.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. It is important to take your oral contraceptive exactly as directed and not miss any doses. Let your doctor know if you notice any changes in your menstrual cycle, such as break-through bleeding. This may be a sign that your contraceptive is not be working as well.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Lamictal (lamotrigine) US prscribing information. GlaxoSmithKline May, 2015.
2.Sidhu J, Job S, Singh S, Philipson R. The pharmacokinetic and pharmacodynamic consequences of the co-administration of lamotrigine and a combined oral contraceptive in healthy female subjects. Br J Clin Pharmacol 2006 Feb;61(2):191-9.
3.Anderson Gail D. Chapter 42: Pharmacokinetics and Drug Interactions. In: Wyllie's Treatment of Epilepsy: Principles and Practice, 5th Ed. 2011.
4.Levy RH Thummel KE Trager WF. Metabolic Drug Interactions (textbook). Metabolic Drug Interactions 2000.