First-Trimester Exposure to Lamictal May Cause Oral CleftSep 29, 2006 | Medscape The US Food and Drug Administration (FDA) has notified healthcare professionals regarding new preliminary information from the North American Antiepileptic Drug Pregnancy Registry (NAAED), advising that fetal exposure to the oral antiepileptic drug (AED) lamotrigine (Lamictal, GlaxoSmithKline) during the first trimester of pregnancy may be linked to an increased risk for cleft lip or palate in newborns.
Because more research is required to confirm this risk, women who are pregnant or thinking of becoming pregnant are urged not to start or discontinue lamotrigine therapy prior to physician consultation, according to an alert sent today from MedWatch, the FDA's safety information and adverse event reporting program.
Oral clefts reported in the NAAED registry were few (5 cases in 564 women: 2 with isolated cleft lip and 3 with isolated left palate); overall prevalence was 8.9 per 1000 live births.
According to the FDA, the cases were not part of a syndrome that included other birth defects, and other pregnancy registries of similar size have not replicated this observation. The prevalence of nonsyndromic oral cleft among infants of nonepileptic mothers not treated with lamotrigine in the United States, Australia, and Europe ranges from 0.5 to 2.16 per 1000 live births.
Also, a comparison of the risk associated with lamotrigine cannot be compared with that of other new AEDs because of the small number of registry-enrolled patients.
Pregnant women who have received or require continuing treatment with lamotrigine during pregnancy may be registered by contacting the NAAED Pregnancy Registry at 1-888-233-2334. Patients may also register in a manufacturer-sponsored registry, which is aimed at obtaining additional data regarding this potential association, by calling 1-800-336-2176.
The FDA notes that because of the risk for medication errors based on the name similarities between lamotrigine (Lamictal) and several other drugs with similar names (eg, Lamaism, lamivudine, Ludiomil, labetalol, and Lomotil), prescribers and pharmacists are advised to ensure that “Lamictal” is written clearly on the script, and patients are encouraged to check the appearance of their medication.
Lamotrigine is indicated as adjunctive therapy for partial seizures, generalized seizures of Lennox-Gastaut syndrome, and primary generalized tonic-clonic seizures in patients aged 2 years and older.
It is also indicated as maintenance therapy to delay the time to occurrence of mood episodes in patients with bipolar I disorder receiving standard acute therapy; and for conversion to monotherapy in adults with partial seizures currently receiving treatment with carbamazepine, phenytoin, phenobarbital, primidone, or valproate as the single AED.
Lamotrigine-related adverse events may be reported to the FDA's MedWatch reporting program by phone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at http://www.fda.gov/medwatch, or by mail to 5600 Fishers Lane, Rockville, MD 20852-9787.