USE OF LAMOTRIGINE IN PREGNANCY

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(Date of issue: January 2020, Version: 3)

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.

A corresponding patient information leaflet on lamotrigine use in pregnancy is available at www.medicinesinpregnancy.org.

Summary

Lamotrigine is an anticonvulsant used either as sole treatment or as adjunctive treatment of focal and generalized seizures, including tonic-clonic seizures and seizures associated with Lennox-Gastaut syndrome. Lamotrigine is also used in the treatment of bipolar disorder.

The available data on lamotrigine use in pregnancy are derived mainly from studies of women with epilepsy. Overall congenital malformation rates have been studied in over 12,800 infants exposed to lamotrigine in early pregnancy; the majority of the data do not provide evidence that lamotrigine use is associated with an increased risk of overall malformation or a number of specific malformations.

There is currently no credible evidence suggesting an increased risk of miscarriage, stillbirth, premature delivery or small for gestational age infants following exposure to lamotrigine. Data regarding adverse neurodevelopmental outcomes following prenatal exposure to lamotrigine are generally reassuring. There are currently no studies which provide evidence of an increased rate of autism diagnoses following prenatal exposure to lamotrigine; however, some studies have reported an increased rate of autism symptoms. Further research is required to confirm or refute this finding.

Lamotrigine is a weak folate antagonist and a single study has reported a statistically significant increased risk of overall malformation in children born to mothers taking lamotrigine who were prescribed <5mg folic acid per day. UK guidelines state that women who take any antiepileptic medication should be prescribed high dose folic acid (5mg).

Use of any centrally acting drug throughout pregnancy or near delivery may be associated with an increased risk of poor neonatal adaptation syndrome (PNAS). These symptoms are likely to be more severe in infants exposed in utero to more than one CNS acting drug. Where lamotrigine has been used during the latter stages of pregnancy, particularly in combination with other CNS acting medications, delivery should be planned in a unit with adequate neonatal facilities.

Plasma concentrations of lamotrigine have been shown to decline as pregnancy progresses and regular clinical review of women taking lamotrigine is therefore recommended. The lamotrigine dose may need to be increased on the basis of plasma-drug concentration monitoring or according to clinical response to maintain seizure control, particularly in later pregnancy.

Lamotrigine should only be used during pregnancy where the benefits of treatment are considered to outweigh any potential risks. Other risk factors may be also present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.

This document is regularly reviewed and updated. Only use full UKTIS monographs downloaded directly from TOXBASE.org to be sure you are using the most up-to-date version. The summaries of these monographs are openly available on UKTIS.org.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at www.toxbase.org.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from TOXBASE.org or UKTIS.org to ensure you are using the most up-to-date version.