Antibiotics and Birth Control: What You Should Know

According to the CDC, approximately 14 percent of U.S. women ages 15–49 — or nine million people — used hormonal birth control pills from 2017–2019.

Millions of women in the United States rely on hormonal birth control for contraception, hormonal regulation, and more. What are the risks to this population when they need antibiotics to fight infection? Which antibiotics are safe to take, and which ones will “cancel out” your birth control?

It can be easy to be led astray by myths and rumors about contraceptives. Here are some facts about the interactions between antibiotics and hormonal birth control. Learn how you can stay healthy while avoiding adverse drug interactions.

Can Antibiotics Affect Hormonal Birth Control?

Patients often ask if antibiotics can increase their risk of pregnancy. In fact, many patients have believed for years that they can’t take antibiotics while on birth control without risking the effectiveness of their hormonal birth control.

Some antibiotics can affect hormonal birth control. While pills might come to mind first, many contraceptives fit into this category, including implants, birth control pills, intrauterine devices (IUDs), vaginal rings, injections, and patches.

Certain antibiotics can make hormonal birth control less effective, increasing your risk of pregnancy. Before starting a new antibiotic, be sure to let your healthcare provider know if you’re using birth control. They can help you take the appropriate steps to prevent pregnancy during your treatment.

Rifamycin Antibiotics Can Impact Hormonal Birth Control

Rifamycin is an antibiotic medication used to treat uncommon bacterial infections. It can decrease the effectiveness of all birth control methods that administer hormones to prevent conception.

This is because rifamycin or rifampin can increase the liver’s production of enzymes that break down hormones in birth control, making them less effective at preventing pregnancy. As a result, you should use a backup method of birth control like condoms or a diaphragm while taking rifamycin and for at least seven days after you complete your treatment.

Luckily, rifamycin is not a commonly-prescribed antibiotic. It’s used to treat tuberculosis, H. pylori, and opportunistic infections in HIV-positive patients. If you’ve been prescribed an antibiotic for a sinus infection, ear infection, or urinary tract infection, it most likely isn’t rifamycin or a related drug. However, it’s important to note that doxycycline, a more common antibiotic used for sexually transmitted infections, rosacea, dental infections, and other issues, can also reduce the effectiveness of your birth control and lead to breakthrough bleeding or pregnancy.

Some forms of birth control are still very effective when taking rifamycin, like copper IUDs, cervical caps, diaphragms, spermicide, and condoms. To reduce your risk of unplanned pregnancy, visit your provider before starting a new medication. Be sure to share your medical history, including any medications and supplements you’re taking and what methods you’re using to prevent pregnancy.

Amoxicillin and Other Penicillin Antibiotics Do Not Impact Birth Control

Amoxicillin, ampicillin, and other penicillins are used to treat a wide variety of infections, including bronchitis, pneumonia, and infections of the nose, throat, ears, skin, and urinary tract. You’re much more likely to be prescribed a penicillin-like antibiotic than rifamycin.

When it comes to amoxicillin and birth control, studies have found that there is no drug interaction. Amoxicillin and other penicillin antibiotics have not been shown to impact the effectiveness of birth control pills or other hormonal contraceptives. The reduction in gut bacteria caused by oral antibiotics doesn’t impact the absorption of hormonal birth control.

Other broad-spectrum antibiotics, including metronidazole or ciprofloxacin, are also safe to take while using hormonal contraceptives.

While there have been a few isolated cases of women experiencing unintended pregnancy while taking antibiotics and using birth control pills, these instances are rare. They are more likely due to user error or other factors. Your doctor can help you understand how to take your contraceptives to ensure efficacy.

Will Plan B Work If I’m Taking Antibiotics?

First, it is important to know how emergency birth control works. Plan B is a form of emergency contraception commonly referred to as the morning-after pill. Plan B can be used to prevent pregnancy after unprotected sex or birth control failure. Like birth control pills, Plan B contains progesterone, which can prevent ovulation, make it difficult for the sperm to reach an egg, or make the uterus uninhabitable for a fertilized egg.

Because Plan B is hormonal, antibiotics and other medications can make it less effective. As is the case with birth control pills, only rifamycin antibiotics (which might have different names, like rifabutin and rifadin) reduce the effectiveness of emergency birth control. Plan B is available over the counter, but connecting with your doctor is the best way to avoid drug interactions and ensure you have selected the most effective birth control option for you.

Talk to your healthcare provider about your options if you are taking antibiotics and considering emergency contraception.

Are There Other Medicines and Supplements That Can Reduce My Birth Control’s Effectiveness?

There are several other medications and supplements that can make your birth control less effective, increasing your risk of conception, including:

• Anticonvulsants: Certain anticonvulsant medications, including carbamazepine, phenytoin, and topiramate, can increase your risk of pregnancy while taking birth control. Anticonvulsants affect birth control by accelerating the metabolism of progesterone and estrogen, decreasing hormonal levels in your bloodstream.
• Antifungal medications: Some antifungal medications like griseofulvin might put you at greater risk of pregnancy, but the likelihood is low. Ask your doctor if you should use backup birth control while taking antifungals.
• St. John’s Wort: This herbal supplement can reduce the effectiveness of birth control by speeding up the metabolism of estrogen and progestin, much like certain antibiotics and anticonvulsants.
• HIV medications: Medications used to treat HIV, like ritonavir and efavirenz, can increase the likelihood of conception while on birth control.

You might not think about the vitamins and minerals you are taking when visiting your provider, but supplements can interact with prescription medications, too. Be sure to inform your doctor about all your medications and supplements.

How Can I Prevent Birth Control Pill Interference?

Birth control is most effective when you take it at the same time every day, do not miss scheduled doses, recognize drug interactions early, and use a backup method when needed.

Because there are many medications and supplements that can make contraceptives less effective, your doctor is the best person to identify potential drug interactions. They can prescribe other medications or provide you with guidance on preventing pregnancy, helping you mitigate risk.

Your doctor can only help you identify potential side effects and interactions if you provide them with all the necessary information. Before starting oral contraceptives, let your provider know about all the medications and supplements you take. Share your complete medical history. Additionally, any time you are prescribed a new medication, ensure the prescribing doctor knows you are taking hormonal birth control. Follow their instructions closely, including using a backup method when taking any medication known to reduce the effectiveness of your birth control.

Stay Informed About Your Health With Us

Whether you are ready to find the right form of birth control for your health and lifestyle or wondering what types of antibiotics are safe to take, the doctors at Tidewater Physicians for Women can help.

Take charge of your health and well-being by visiting our obstetrics and gynecology team at Tidewater Physicians for Women today. From routine check-ups and medical advice to problem-focused exams, our expert physicians, nurse practitioners, and licensed counselors are here to assist you. Take the first step toward a healthier you and schedule an appointment by calling 757-461-3890 today.