Medication Adverse Event Alert
October 10, 2006
MEDICATION: Lamotrigine
| Description: | Approved for use in treating partial seizures and bipolar I disorder |
| Dosage: | Available as standard and chewable tablets |
| Manufacturer: | GlaxoSmithKline (Lamictal), Teva USA (generic) |
| Strength: | Tablets 25mg, 100mg, 150mg, 200mg, chewable tabs 2mg, 5mg & 25mg |
Event Description: The FDA announced that recent data from the North American Antiepileptic Drug (NAAED) Pregnancy Registry suggest a possible link between lamotrigine use during the 1st trimester of pregnancy and cleft lip and/or cleft palate. It reported that the total prevalence reported for oral cleft cases among lamotrigine-exposed infants is 8.9 per 1000 as compared to 0.50 to 2.16 in studies with non-exposed infants (Holmes et.al). However, other pregnancy registries of similar size have not reported such results. Thus the FDA alert concludes “the validity of this possible association cannot be established until further data are collected in the NAAED Pregnancy Registry, in other ongoing pregnancy registries, or through other research efforts. The clinical significance of this preliminary report is thus uncertain”
Clinical Considerations and Recommendations: Healthcare professional providing lamotrigine therapy to childbearing age women should consider the following issues.
- The risks to pregnant women and unborn children with untreated epilepsy or bipolar disorder must be weighed with possible risks of using lamotrigine.
- The reported association between oral cleft cases and lamotrigine therapy is not absolute and needs further data and research to substantiate.
- The NAAED Pregnancy Registry has confirmed an association between major malformations and the Antiepileptic drugs phenobarbital and valproate.
- The current registries pertaining to newer antiepileptic drugs do not have sufficient numbers of pregnant women to provide an estimate of comparative risk among these drugs for causing fetal harm.
Further Implications: The FDA considers this report on lamotrigine exposure and increased incidence of fetal oral cleft as preliminary and has not reached a final conclusion on a positive link. Further updates are expected as more information becomes available.
