Birth Control and Other Medication Interactions: What You Should Know 

She was picking up a new prescription when the pharmacist asked, “Are you currently using birth control?”

The question caught her off guard. The new medication had nothing to do with reproductive health—or so she thought.

Then the pharmacist explained that certain medications can make some birth control methods less effective. In other situations, birth control can change how another medication works.

That quick conversation could help prevent an unintended pregnancy or a change in treatment effectiveness.

Can Medication Make Birth Control Less Effective?

Yes, but it depends on both the medication and the type of birth control being used.

Some medications cause the body to break down contraceptive hormones more quickly. This may lower hormone levels and reduce the effectiveness of certain birth control pills, patches, rings, or implants.

Rifampin and Related Antibiotics

Many patients have heard that all antibiotics interfere with birth control. Fortunately, most commonly used broad-spectrum antibiotics do not reduce the effectiveness of birth control pills, patches, or rings.

The important exceptions include rifampin and rifabutin, which can lower contraceptive hormone levels and make certain hormonal methods less reliable.

St. John’s Wort

St. John’s wort is an herbal supplement sometimes used for mood symptoms. It can speed up the breakdown of birth control hormones and may make hormonal contraception less effective.

Even though it is sold without a prescription, it should still be included on your medication list.

Tirzepatide

Tirzepatide, the active ingredient in medications such as Zepbound and Mounjaro, can delay stomach emptying and may affect the absorption of oral hormonal contraceptives.

Current prescribing information advises patients using oral hormonal birth control to switch to a non-oral method or add a barrier method for four weeks after starting tirzepatide and for four weeks after every dose increase.

Can Birth Control Affect Another Medication?

Sometimes the interaction works in the opposite direction.

Estrogen-containing oral contraceptives can significantly lower levels of lamotrigine, a medication used for seizures and certain mood disorders. This may reduce lamotrigine’s effectiveness and, in some patients, increase seizure activity. Lamotrigine levels may also rise during the hormone-free week of certain pill packs.

Medication doses should not be adjusted or stopped without speaking with the prescribing provider.

What Should You Do Before Starting a New Medication?

Back at the pharmacy counter, the pharmacist did not automatically tell the patient to stop her medication or birth control. Instead, they reviewed the exact products she was taking.

That detail matters because “birth control” can mean many different things, including:

• A daily pill
• A patch or vaginal ring
• An implant
• An injection
• A hormonal or nonhormonal IUD

Before starting a prescription, over-the-counter medication, or herbal supplement, tell your pharmacist and prescriber which birth control method you use.

Ask whether you need:

• A temporary backup method
• A different form of contraception
• Additional monitoring
• A change to another medication

Do not stop either medication on your own. The right recommendation depends on the specific drugs, doses, and contraceptive method.

The Bottom Line

Most medications do not interfere with birth control—but some important ones can.

That is why a pharmacist may ask about birth control while filling a prescription that seems completely unrelated. It is not an unnecessary question. It is one more way to make sure all your medications work safely together.

Written by:

Vaishnavi Shah 

Resources 

• Birth Control and Medication Interactions: How Drugs and Supplements Can Affect the Pill
• What Medications Interfere With Birth Control Pills? 

This article is for general educational purposes and does not replace individualized medical advice. Speak with your pharmacist or healthcare provider before starting or stopping medication or changing your birth control method.