OBJECT DRUGS
- Lamotrigine (Lamictal, etc.)
PRECIPITANT DRUGS
Comment:
Combined oral contraceptives have been shown in several studies to substantially reduce lamotrigine plasma concentrations; reduced lamotrigine efficacy may occur. The most likely mechanism is enhanced lamotrigine glucuronidation caused by the estrogen component, ethinyl estradiol.
Class 3: Assess Risk & Take Action if Necessary
- Consider Alternative: Preliminary evidence suggests that progestogen-only contraceptives (regardless of method of administration) do not affect lamotrigine concentrations, but more study is needed. Many antiepileptic drugs interact with oral contraceptives by various mechanisms, so one must choose such combinations carefully.
- Monitor: If lamotrigine and oral contraceptives are used concurrently monitor for altered lamotrigine effect if an oral contraceptive is started, stopped, or if the patient is switched to a contraceptive product with a different hormone content.