Antibiotics and Birth Control Pill Interactions

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on March 12, 2024.

Can you take antibiotics with birth control?

Today, most research states that antibiotics (with the exception of rifamycins like rifampin, rifabutin or rifapentine used for tuberculosis), do not alter the effectiveness of hormonal forms of birth control that are absorbed into the blood (for example: the pill, patch or vaginal ring).

However, critics maintain that many studies that have found a lack of an interaction have been small and therefore unlikely to detect infrequent interactions. Because some studies are conflicting, you should discuss this topic with your healthcare provider if you are prescribed an antibiotic and you use a hormonal form of birth control.

Vomiting or having diarrhea, which can be common with antibiotic treatment, may also lower how well an oral contraceptive (like the pill) prevents pregnancy, too. Use a back-up method like a condom in these circumstances until you can talk to your healthcare provider. 

What does the research say?

According to the clinical advice, experts and women’s health providers, only one antibiotic - rifampin, and possibly rifabutin and rifapentine - have been shown to make the birth control pill less effective.

A 2018 review published in the American Journal of Obstetrics and Gynecology concurred with this information. Researchers completed a literature review of multiple studies. The authors concluded that most women can expect no reduction in effectiveness with the use of hormonal contraceptives and antibiotics (except for rifamycins).

A review from the Journal of the American Academy of Dermatology states that pharmacokinetic evidence demonstrates that levels of oral contraceptive steroids are unchanged with combined administration of antibiotics, including:

• ampicillin
• ciprofloxacin
• clarithromycin
• doxycycline
• metronidazole
• ofloxacin
• roxithromycin (not available in the US)
• tetracycline

Even with this study data and expert opinions, the association between antibiotic use and contraceptive failure is still controversial. Large clinical trials have not been completed, but many individual studies have been evaluated. Some experts argue that studies are too small or poorly designed to determine the interactions between individual antibiotics and birth control.

A large but observational database study from BMJ Evidence-Based Medicine published in August 2020 suggests that there is a possibility of pregnancy when birth control and antibiotics are combined. However, this study could not prove this based on the design (retrospective) and limitations of the research. The study was based on self-reports from participants and therefore was subject to recall bias.

• Researchers reviewed an analysis of reported unwanted side effects (called Yellow Cards in the UK) and found that unintended pregnancies were 7 times more likely for those taking antibiotics than for other types of unrelated drugs.
• The authors concluded that women on hormonal contraceptives should be advised to use extra precautions to avoid unintended pregnancy when prescribed antibiotics.
• However, this study has been criticized based on its study design and need for recall bias.

Which birth control do you use with rifampin?

A nonhormonal method of birth control - for example, a condom, diaphragm, or copper IUD, is recommended with rifampin use (or any other rifamycin). Depo-Provera, the progestin birth control shot, or a progestin IUD like Skyla, Mirena or Kyleena, may be other options.

Rifmapin is used for tuberbuculosis but is not widely prescribed today. Rifampin and other rifamycins can lower birth control hormone levels (ethinyl estradiol and progestin) in women taking oral contraceptives. Rifampin can induce enzymes in your liver that will break down hormone levels faster than normal. Lowering hormone levels can lead to ovulation and reduce the effectiveness of your birth control. 

Rifampin can also lower the effectiveness of the transdermal birth control patch (example: Xulane) and the vaginal ring (examples: NuvaRing, EluRyng, Annovera), so an added barrier method of birth control like a condom or diaphragm should be used with these products.

Tubal ligation may be an option for those taking rifampin who prefer a permanent birth control method.

Talk to your doctor about birth control options before you start treatment if you plan on taking rifampin or another rifamycin antibiotic. 

Related: Can antibiotics affect IUDs like Kyleena, Mirena, or Skyla?

What other types of drugs can alter birth control effectiveness?

Other types of drugs besides the antibiotics rifampin or the rifamycins may affect birth control reliability due to enzyme changes in your body. These include drugs like anticonvulsants, some antifungals, certain HIV medicines and even the herbal product St. John's Wort.

Therefore, always have your doctor or pharmacist complete a drug interaction review any time you start or even stop a medication. This includes prescription medicines, as well as over-the-counter (OTC) drugs, vitamin and herbal or dietary supplements.

Examples

The antifungal medicine griseofulvin may lead to lower levels of birth control hormones and reduce the effectiveness of birth control pills.

Certain seizures drugs can also lower the effectiveness of combined birth control pills, for example anticonvulsant medications such as:

• carbamazepine (Tegretol)
• phenytoin (Dilantin)
• primidone (Mysoline)
• topiramate (Topamax, Qudexy XR)
• felbamate (Felbatol)
• oxcarbazepine (Oxtellar XR, Trileptal)
• and barbiturates like phenobarbital

Some HIV medications, such as efavirenz, protease inhibitors, or antiviral boosters may also affect birth control effectiveness.

Two small studies suggest that St. John's wort can induce liver enzymes, which may increase birth control pill metabolism and reduce therapeutic efficacy. This may be possible with the patch and birth control ring, too.

If you’re taking any of these drugs, use condoms (or other reliable barrier method) as a backup form of birth control. Talk to your doctor about switching to a different nonhormonal method of birth control (for example: the copper IUD or a diaphragm) if you’ll be on these interacting drugs for a long time.

And remember, the main reason women get pregnant when using the pill is because they do not take it correctly. Birth control pills fail at least 1% of the time in perfect conditions, and up to 9% of the time with typical use, so taking your pill as directed or faithfully using other reliable contraceptive methods are the key to pregnancy prevention.

• Learn more: Missed taking your birth control pill? Here's what to do next.
• See Planned Parenthood for more information.

This is not a complete list of all possible interactions with birth control. Use the Drugs.com Interaction Checker to review for possible drug interactions with your birth control method and review them with your doctor or pharmacist.

See also

• Antibiotic Resistance: The Top 10 List
• Antibiotics - Common Side Effects, Allergies and Reactions
• Antibiotics for UTI Treatment
• Can You Drink Alcohol with Antibiotics?
• Middle Ear Infection FAQs (Acute Otitis Media)
• Why Don’t Antibiotics Kill Viruses?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer