Do any medications cancel out birth control? The facts on drug interactions and contraception

October 9, 2025 •

4 min read

According to the CDC, approximately 14 percent of U.S. women rely on hormonal birth control, making it a critical aspect of their healthcare. However, the effectiveness of these contraceptives can be compromised by certain medications and supplements, raising the important question: Do any medications cancel out birth control?.

Quick Summary

Certain medications and supplements can interfere with hormonal birth control by accelerating hormone metabolism or affecting absorption, potentially reducing contraceptive effectiveness. This risk varies depending on the specific medication, dosage, and type of birth control used, necessitating caution and consultation with a healthcare provider.

Key Points

Drug Classes: Certain anticonvulsants, the antibiotic rifampin, some HIV medications, and the herbal supplement St. John's Wort are known to reduce birth control effectiveness.
Mechanism of Action: Many interacting drugs act as enzyme inducers, causing the liver to break down contraceptive hormones faster and lowering their effectiveness.
Common Antibiotics: Most common antibiotics, like amoxicillin or doxycycline, do not interact with birth control and do not require backup contraception.
Essential Action: Always inform your healthcare provider or pharmacist about all medications and supplements you take, including over-the-counter products, to check for potential interactions.
Backup Protection: Using a non-hormonal backup method, like condoms, is the most reliable way to prevent unintended pregnancy when taking an interacting medication.
Vomiting and Diarrhea: Severe or prolonged gastrointestinal distress can affect the absorption of oral contraceptives, necessitating a backup method.
Contraceptive Type: Non-hormonal birth control methods, such as the copper IUD, are unaffected by drug interactions.

Understanding Drug Interactions with Birth Control

When considering your birth control method, it's crucial to understand that not all drugs are compatible with hormonal contraceptives. While many common medications, including most antibiotics for routine illnesses, do not affect birth control, some specific drug classes and supplements can interfere. This interference typically happens in one of two ways: either by accelerating the metabolism of hormones in the liver or by disrupting the body's absorption of the contraceptive.

The Role of Liver Enzymes

Many hormonal contraceptives are metabolized by the liver using a group of enzymes called the cytochrome P450 system. Certain medications act as "enzyme inducers," meaning they cause the liver to produce more of these enzymes. This heightened activity can break down the birth control hormones (estrogen and progestin) faster than normal, leading to lower hormone levels in the body. With insufficient hormone levels, the contraceptive effect is diminished, increasing the risk of ovulation and unintended pregnancy.

Which Medications Pose a Risk?

Several categories of drugs and supplements are known to interact with hormonal birth control. Awareness of these is essential for anyone using the pill, patch, ring, or implant.

Anticonvulsants: Certain medications used to treat seizures and epilepsy are potent enzyme inducers. These include carbamazepine (Tegretol), phenytoin (Dilantin), phenobarbital, and topiramate (Topamax). The interaction with hormonal birth control is significant and often requires using a non-hormonal backup method of contraception.
Antibiotics: This is a common point of confusion. While the majority of broad-spectrum antibiotics (like amoxicillin and doxycycline) are not proven to interfere with hormonal contraception, one specific antibiotic, rifampin (used to treat tuberculosis), is a well-documented enzyme inducer. When taking rifampin, a backup birth control method is strongly recommended.
Antifungal Medications: The antifungal drug griseofulvin can reduce the effectiveness of oral contraceptives by affecting liver enzymes. A backup method is advised during treatment and for a period afterward.
HIV Medications: Some antiretroviral drugs used to treat HIV can interact with hormonal birth control. These interactions can be complex and are best managed under a doctor's supervision.
Herbal Supplements: The most well-known herbal culprit is St. John's Wort, an over-the-counter supplement often used for depression. It is a powerful enzyme inducer that can speed up the metabolism of birth control hormones, leading to breakthrough bleeding and potential contraceptive failure.

Potential Interactions with Birth Control Methods

Not all birth control methods are affected by interacting medications in the same way. The mechanism of action and delivery system are key factors.

Oral Contraceptives (The Pill): Most susceptible to interactions that speed up liver metabolism because the hormones must pass through the digestive system and liver before entering the bloodstream.
The Patch and Ring: Also affected by enzyme-inducing drugs, as their hormones are also absorbed into the bloodstream and metabolized by the liver.
The Implant (Nexplanon): Though less affected than the pill, its effectiveness can also be reduced by enzyme-inducing medications.
Hormonal IUDs (Mirena, Liletta): These release hormones locally within the uterus, meaning they are less affected by systemic drug interactions.
Non-Hormonal Methods (Copper IUD, condoms): These are not affected by medications and offer a reliable backup option when using an interacting drug.

Comparison of Medication Interactions and Contraception


Medication Type	Common Examples	How it Affects Birth Control	Recommended Action
Anticonvulsants	Carbamazepine, Phenytoin, Topiramate	Increases liver enzymes, breaking down hormones faster and reducing effectiveness.	Use a non-hormonal backup method.
Antibiotics	Rifampin (for TB)	Increases liver enzyme activity, significantly reducing hormonal levels.	Use a backup method during treatment and for at least 7 days after.
HIV Medications	Efavirenz, Ritonavir	Certain antiretrovirals can alter hormone levels, decreasing contraceptive efficacy.	Discuss with your doctor for optimal regimen and use a backup method.
Herbal Supplements	St. John's Wort	Induces liver enzymes, speeding up hormone metabolism.	Use a non-hormonal backup or choose a different depression treatment.
Common OTC Painkillers	Acetaminophen, Ibuprofen	No significant interaction with birth control effectiveness.	Safe to use as directed.

Navigating Drug Interactions and Ensuring Protection

For anyone using hormonal birth control, the best defense is to be informed and proactive. When starting a new medication, whether prescription or over-the-counter, or a new supplement, it is essential to consult with a healthcare professional. A pharmacist or doctor can review your current medications and determine if there is a risk of interaction.

To ensure your protection is not compromised, consider these steps:

Maintain an up-to-date medication list: Keep a record of all prescription drugs, over-the-counter medications, and supplements you take. Share this with your healthcare provider and pharmacist.
Use backup contraception: If you are prescribed a medication that interacts with your birth control, a non-hormonal backup method like condoms can provide peace of mind and prevent unintended pregnancy.
Be aware of other factors: Events like vomiting and severe diarrhea can also reduce the absorption of oral contraceptives, so a backup method is advised in these instances as well.
Consider alternative birth control: If you require a long-term medication that significantly interacts with your hormonal contraceptive, discuss alternative options with your doctor, such as an IUD, which is not affected by liver enzyme induction.

Conclusion

While the vast majority of common medications do not interfere with hormonal birth control, a select few can compromise its effectiveness by altering hormone levels. Key culprits include certain anticonvulsants, the antibiotic rifampin, some HIV medications, and the herbal supplement St. John's Wort. It is not about a medication “canceling out” birth control in a single instance, but rather a persistent drug interaction that reduces its reliability. The safest approach is always to consult with a healthcare provider or pharmacist whenever starting a new drug. Being proactive and using a backup method of contraception when necessary is the most effective way to ensure continued protection against unintended pregnancy.

For more detailed information on specific drug interactions, you can consult with resources like the Drugs.com Interaction Checker.

Frequently Asked Questions

Yes, you can take most antibiotics with birth control. Only a few specific antibiotics, most notably rifampin used for treating tuberculosis, have been proven to significantly reduce the effectiveness of hormonal birth control. For any concerns, consult with your doctor or pharmacist.

If you are taking a medication known to interfere with birth control, use a backup, non-hormonal contraceptive method, such as condoms. Continue to use the backup method for the duration of the interacting medication and for at least seven days after stopping it.

Yes, St. John's Wort is a powerful enzyme inducer that can speed up the metabolism of hormonal birth control, making it less effective. It is strongly advised to use a non-hormonal backup method or to use a different depression treatment.

No, common over-the-counter painkillers like ibuprofen (Advil) and acetaminophen (Tylenol) do not affect the effectiveness of hormonal birth control pills.

Some antiretroviral drugs used for HIV can significantly interact with hormonal contraception. It is crucial to work with your healthcare provider to choose an appropriate birth control method and HIV treatment plan.

Always inform your doctor or pharmacist about all the medications and supplements you are taking. Pharmacists are excellent resources for checking drug interactions. You can also consult online drug interaction checkers, but always discuss findings with a healthcare professional.

No, taking birth control at night, for example, does not inherently alter its effectiveness, but taking it consistently at the same time each day helps maintain steady hormone levels. If you vomit or have severe diarrhea soon after taking your pill, its absorption may be affected, requiring a backup method.