Narcolepsy medicine linked to increased risk of birth defects, warns medicines regulator

A US study found that more babies with foetal exposure to modafinil were born with major congenital anomalies than those in the general population.


The narcolepsy medicine modafinil should not be taken during pregnancy, owing to an increased risk of congenital malformations, the Medicines and Healthcare products Regulatory Agency (MHRA) has warned.

The regulator’s warning follows a review of data from the US, which found that of 61 pregnancies with foetal exposure to modafinil, 9 babies (15%) were born with major congenital anomalies — a higher prevalence than in the general population (3%).

The data were published as part of a study established in 2010 to characterise the pregnancy and foetal outcomes associated with exposure to modafinil and armodafinil, from six weeks before conception and during pregnancy.

In a drug safety update published on 16 November 2020, the MHRA said the data have “shown that the prevalence of major congenital malformations is above the background rate in the general population”.

As a result, the regulator has advised healthcare professionals to warn female patients of childbearing potential on modafinil of the risks associated with taking it during pregnancy, and ensure they use effective contraception during treatment and for two months after treatment has finished.

However, the MHRA said modafinil may reduce the effectiveness of steroidal contraceptives and advised that patients use long-term methods such as a copper intrauterine device, levonorgestrel-releasing intrauterine system or depot progestogen-only injections instead.

Some 83,665 items of modafinil were prescribed in England in 2019, according to prescription cost analysis data published by the NHS Business Services Authority for 2019.

The warning comes after a survey found that just under half of pharmacists are not discussing the risks of taking sodium valproate when dispensing the drug to women.

Sodium valproate, which has also been found to have teratogenic potential, was partly the focus of the Independent Medicines and Medical Devices Safety Review that called for a register of all women taking antiepileptic drugs who become pregnant.

Sarah Branch, director of the MHRA’s vigilance and risk management of medicines division, said: “It is important that women are aware of the increased risk of congenital malformations associated with taking modafinil during pregnancy.

“Modafinil can reduce the effectiveness of many hormonal contraceptives, including the pill. Women should discuss their options with their healthcare professional and continue to use their contraceptive for two months after stopping modafinil.”


Last updated
The Pharmaceutical Journal, PJ December 2020, Vol 305, No 7944;305(7944):DOI:10.1211/PJ.2020.20208562

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