Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some drugs may cause hormonal birth control to work less well by decreasing the amount of birth control hormones in your body. This effect can result in pregnancy. Examples include griseofulvin, modafinil, rifamycins (such as rifampin, rifabutin), ritonavir, St. John's wort, drugs used to treat seizures (such as barbiturates, carbamazepine, felbamate, phenytoin, primidone, topiramate), HIV drugs (such as nelfinavir, nevirapine), among others.

Tell your doctor when you start any new drug, and discuss if you should use reliable backup birth control. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.

This medication may interfere with certain lab tests (such as sex hormone-binding globulin, thyroid), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.