Before starting modafinil, women of childbearing potential must be informed of the risk of teratogenicity. Patients must use effective contraception during treatment with modafinil and for 2 months after stopping.
Modafinil may reduce the effectiveness of steroidal contraceptives, including oral contraceptives, through the induction of CYP3A4/5. Alternative or concomitant methods of contraception are required.
Guidance is available on interactions with contraception from the Faculty of Sexual and Reproductive Healthcare Clinical Effectiveness Unit (January 2017, last reviewed 2019). For enzyme-inducing medicines such as modafinil, the guidance recommends avoiding combined hormonal contraception (CHC) pills, rings, and patches; progestogen-only pill; progestogen-only implants; and ulipristal acetate emergency contraception.
The guidance states that suitable long-term methods are copper intrauterine device (copper IUD), levonorgestrel-releasing intrauterine system (LNG-IUS), and depot progestogen-only injections. For emergency contraception, if a copper IUD is not suitable, a double dose of oral levonorgestrel emergency contraception is advised – see the product information for levonorgestrel.
The guidance recommends that if use of modafinil is only anticipated for a short time (2 months), barrier methods in conjunction with existing contraceptives may be advised.
When using any medicine with teratogenic potential, a woman should be advised of the risks and encouraged to use the most effective contraceptive method taking into account her personal circumstances. See Drug Safety Update March 2019 for guidance on contraceptive methods and frequency of pregnancy testing to reduce inadvertent exposures during pregnancy in a woman taking a medicine of teratogenic potential. Women of childbearing potential planning a pregnancy should be advised on the need to discuss other narcolepsy treatment options with their doctor before stopping contraception