Medicines Which Could Be Messing Up Your Birth Control

Hormonal contraceptive methods are widely used by people of all ages to prevent pregnancy but certain kinds, like the pill can be rendered ineffective when taken in combination with other widely prescribed medicines. Take a look at our list and always refer to a doctor if you have questions.

*Article content should not be interpreted as professional medical advice. Please consult a doctor with any questions or concerns.*

Have you ever wondered which medicines interfere with your birth control? Here, we’ll take you through a few medications which might be lowering the effectiveness of your contraceptive methods. 

According to the Mayo Clinic, oral contraceptives – which are taken orally, or swallowed – are known as the Pill, OCs, BCs, BC tablets or birth control pills. This medicine usually contains two types of hormones: estrogens and progestins. When taken properly, oral contraceptives prevent pregnancy.

Hormonal contraceptives can include the birth control pill, the vaginal ring, the contraceptive skin patch and hormone-releasing contraceptive coils, according to the National Center for Biotechnology Information.


Antibiotics are also known as antibacterials, and are used to treat infections by slowing the growth of bacteria. 

In a 1999 study published by the NCBI, researchers investigated the effects of the interaction between oral contraceptives and antibiotics.

The study found rifampin is the only antibiotic that has been reported to reduce plasma estrogen concentrations, meaning oral contraceptives cannot be relied upon for birth control while taking rifampin.

According to MedlinePlus, rifampin is an antibiotic often used with other medications to prevent and treat tuberculosis, neisseria meningitidis and other infections.


Anticonvulsants are medications that calm hyperactivity in the brain in various ways. It is often used for epilepsy and to prevent migraines.

Phenytoin is the most common anticonvulsant reported to cause oral contraceptive failure, according to the NCBI. 

Wakefulness drugs

Provigil, which is also known as modafinil, is a prescription medicine used to improve wakefulness in adults who are very sleepy, according to the Food and Drug Administration. People who use provigil might have one of the following diagnosed sleep disorders: narcolepsy, obstructive sleep apnea and shift work disorder. 

This medication interferes with birth control methods, such as birth control pills, shots, implants, patches, vaginal rings and intrauterine devices. The FDA recommends that women taking this medication talk to their doctor for alternative contraceptive methods.

Over-the-counter medications

A 2005 study published by the NCBI found the over-the-counter medicine St. John’s Wort makes oral contraceptives less effective. St.John’s Wort is an herbal remedy most commonly used for mild to moderate depression, mood disorders and symptoms of menopause.

The conclusion of the study stated, “women using OCs should be cautioned that St. John’s Wort might interfere with contraceptive effectiveness.”

The takeaway

People using any kind of contraception method should be aware that some medications will make their birth control less effective and increase their chance of getting pregnant. 

To avoid this risk, it is always a good practice to talk with your doctor about all over-the-counter and prescription medications you are taking.

OSU resources

Oregon State University Student Health Services offers comprehensive sexual health care, gynecologic care, information and testing. All students are encouraged to visit, regardless of gender.

Oregon Health Plan Contraceptive Care is free for all students who qualify. This federal program provides free contraceptive services, birth control and reproductive health care to everyone, regardless of gender.

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