The progestin-only pill may interfere with other medications, which can make it less effective. It’s very important then to let us know if you’re currently taking any other medications.
Progestin-only pills that contain norethindrone are known to interfere with:
St John’s wort
HIV medication
Griseofulvin (used to treat fungal infections)
Modafinil (treats sleeping disorders)
treatment for seizures
antibiotics