Other safety alerts
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| The United Kingdom: Topiramate (Topamax): introduction of new safety measures, including a Pregnancy Prevention Programme |
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Medicines and Healthcare products Regulatory Agency (MHRA) announces that Topiramate is now contraindicated in pregnancy and in women of childbearing potential unless the conditions of a Pregnancy Prevention Programme are fulfilled. This follows a review by the MHRA which concluded that the use of topiramate during pregnancy is associated with significant harm to the unborn child. Harms included a higher risk of congenital malformation, low birth weight and a potential increased risk of intellectual disability, autistic spectrum disorder and attention deficit hyperactivity disorder in children of mothers taking topiramate during pregnancy.
Topiramate is indicated for the prophylaxis of migraine and for the treatment of epilepsy. It is available as tablets, a liquid oral solution and as capsules that can be swallowed whole or sprinkled on soft food. The brand name of topiramate is Topamax, and so this may also appear on the box. Topiramate has been contraindicated in pregnancy for the prophylaxis of migraine since 2010.
Following a comprehensive review of the safety of antiseizure medications in pregnancy, including topiramate, new safety advice was published in January 2021. Since then, new study data has become available reporting a potential increased risk of autism spectrum disorder and effects on learning development in children exposed to topiramate during pregnancy. These new data, and data suggesting increasing use of topiramate in women of childbearing age, triggered a new safety review. This review examined the available data on the risk of congenital malformations, effects on growth and development of the baby, and the risk of neurodevelopmental disorders when topiramate is used during pregnancy.
The review concluded that the use of topiramate during pregnancy is associated with significant harm to the unborn child (both from the confirmed risks of congenital malformations and low birth weight and the potential risk of neurodevelopmental disorders). The accumulating data suggest that:
- Topiramate is amongst the antiseizure medications associated with a higher risk of congenital malformations (approximately 4 to 9 per 100 babies compared to around 1 to 3 babies in every 100 in the general population)
- The risk of congenital malformations with topiramate appears to be dose-dependent, however, a threshold dose below which no risk exists cannot be established
- Topiramate is associated with a high prevalence of babies being born small for gestational age and weighing less at birth (approximately 18 per 100 babies affected); this is higher than the risk in babies born to women with epilepsy not taking antiseizure medication (approximately 5 in 100 babies affected) and may be higher than the risk with some other antiseizure medications
- Topiramate may be associated with an approximately 2 to 3 times increased risk of intellectual disability, autistic spectrum disorders and attention deficit hyperactivity disorder compared with children born to mothers with epilepsy not taking antiseizure medication.
Due to the accumulating data on these harms, further restrictions are being introduced with regards to the use of topiramate in women of childbearing potential and in pregnancy. The use of topiramate is now contraindicated:
- in women of childbearing potential unless the conditions of the Pregnancy Prevention Programme are fulfilled (for all indications)
- in pregnancy for prophylaxis of migraine
- in pregnancy for epilepsy unless there is no other suitable treatment.
General advice for healthcare professionals:
- Topiramate should not be used in pregnancy for prophylaxis of migraine, and in pregnancy for epilepsy unless there is no other suitable treatment.
- Topiramate should not be used in women of childbearing potential unless the conditions of the Pregnancy Prevention Programme are fulfilled. This aims to ensure that all women of childbearing potential are using highly effective contraception, have a pregnancy test to exclude pregnancy before starting topiramate and are aware of the risks from use of topiramate.
Please refer to the following website in MHRA for details:
http://www.gov.uk/drug-safety-update/topiramate-topamax-introduction-of-new-safety-measures-including-a-pregnancy-prevention-programme
In Hong Kong, there are 26 registered pharmaceutical products containing topiramate. All products are prescription-only medicines. So far, with regard to topiramate, the Department of Health (DH) has received 5 cases of adverse drug reaction, but these cases were not related to birth defects.
Currently, the package insert and/or sales pack label of locally registered topiramate-containing products should include safety information on fetal harm and the increased risk of cleft lip and/or cleft palate (oral clefts) in infants exposed to topiramate in utero.
Related news on the risk of birth defects associated with the use of topiramate during pregnancy was previously issued by various overseas drug regulatory authorities, and was posted on the Drug Office website since 9 Jul 2022, with the latest update posted on 4 Sep 2023.
Letters to inform local healthcare professionals were issued by the DH on 4 Sep 2023. As previously reported, the matter will be discussed by the Registration Committee of the Pharmacy and Poisons Board.
Ends/Friday, Jun 21, 2024
Issued at HKT 17:30
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