Some medicines can interfere with how birth control pills work. For example, you may not be protected from pregnancy while you are taking other medicines that affect liver metabolism. The vaginal ring and skin patch contain combination hormones and may also interact with some medicines. The progestin-only pills, implant (Implanon), and shot (Depo-Provera) also contain hormones that may interact with some medicines.

Taking medicines while you are using hormonal birth control may increase your risk of problems. Some combinations of medicine may affect the birth control hormones in your body, making them too strong or too weak. This may increase your chance of getting pregnant. Or a new medicine may be less likely to work because you have birth control hormones in your body. Talk with your doctor or pharmacist to make sure that any medicines you take are not causing problems when you are using hormonal birth control.

Birth control pills may increase your sensitivity to the effects of caffeine.