Plan B (Levonorgestrel) - Oral

What Is Plan B?

Plan B is available as an over-the-counter (OTC) emergency contraceptive tablet used within three days of unprotected sex or suspected failure of another birth control method—like a condom breaking.

Plan B contains levonorgestrel, which is a second-generation progestin. Progestin is a human-made version of progesterone, which is a naturally occurring sex hormone.

Plan B typically prevents pregnancy by stopping ovulation, which is the release of an egg from the ovary. If the egg is already released, then Plan B may also prevent the sperm from fertilizing (meeting and combining with) the egg.

If the sperm has already fertilized the egg, then Plan B may also block the fertilized egg from attaching to the endometrium, which is the uterine lining.

However, if you’re already pregnant, Plan B will not interfere with an existing pregnancy when the fertilized egg is already attached to the uterus.

Drug Facts

Generic Name: Levonorgestrel

Brand Name(s): Plan B, Aftera, EContra, My Choice, My Way, New Day, Next Choice, Opcicon, React, Take Action

Drug Availability: Over the counter (OTC)

Therapeutic Classification: Emergency contraceptive

Available Generically: Yes

Controlled Substance: No

Administration Route: Oral (by mouth)

Active Ingredient: Levonorgestrel

Dosage Form(s): Oral levonorgestrel is available as a tablet.

What Is Plan B Used For?

Plan B is used as an emergency contraceptive to prevent pregnancy.

Every year, there are more than 200 million pregnancies worldwide. In the United States, there is a large number of unintended pregnancies—especially in people assigned female at birth with low incomes. In fact, around 50% of pregnancies are unplanned.

People assigned female at birth can also experience many barriers that block the ability to access birth control easily and appropriately use them.

Therefore, experts recommend and support better access to emergency contraceptives. As an over-the-counter (OTC) product, Plan B is a more easily accessible emergency contractive option.

How to Take Plan B

Take Plan B by mouth as soon as possible within three days of unsafe sex or suspected birth control failure.

If you throw up within two hours of taking Plan B, you might need to take another dose. If you have questions, reach out to your pharmacist or healthcare provider.

Storage

Because Plan B is an over-the-counter product, you can purchase this medication without a prescription from your healthcare provider. If your healthcare provider gave you a prescription for Plan B, they could authorize up to one year's worth of refills from the original date on the prescription.

After bringing Plan B home, you can store this medication at room temperature between 68 degrees and 77 degrees Fahrenheit. Do not store your medicines in the bathroom.

Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet.

Avoid pouring unused and expired drugs down the drain or in the toilet. Ask your pharmacist or healthcare provider about the best ways to dispose of this medicine. Visit the FDA's website to know where and how to discard all unused and expired drugs. You can also find disposal boxes in your area. Ask your pharmacist or healthcare provider if you have any questions about the best ways to dispose of your medications.

If you travel with Plan B, get familiar with your final destination's regulations. Make sure to make a copy of your Plan B prescription. Keep your medication in its original container from your pharmacy with your name on the label. Ask your pharmacist or healthcare provider if you have any questions about traveling with your medicine.

How Long Does Plan B Take to Work?

If taken as soon as possible within three days of unsafe sex or birth control failure, Plan B is effective at lowering your pregnancy risk.
You will know that Plan B worked when you have your next menstrual period. You should experience your menstrual period within a week of the next expected time. If your period is more than one week late, reach out to your healthcare provider to rule out pregnancy.

What Are the Side Effects of Plan B?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Some common side effects of Plan B include:

  • Breast tenderness
  • Dizziness
  • Earlier or later period than expected
  • Headache
  • Heavier or lighter period
  • Lower stomach pain
  • Nausea
  • Tiredness

Severe Side Effects

Having your period earlier or later is typical with Plan B. However, if your period is more than one week later than expected, reach out to your healthcare provider to rule out pregnancy.

While stomach pain is another common side effect of Plan B, it can be excessive and serious. If you believe you’re experiencing severe stomach pain, get medical help immediately. You might have an ectopic pregnancy. In an ectopic pregnancy, the fertilized egg didn’t attach to the uterus. Instead, the fertilized egg attaches to another place—like your fallopian tube or ovary.

Long-Term Side Effects

If your menstrual period is more than one week later than expected, reach out to your healthcare provider to rule out pregnancy. Additionally, if you are experiencing severe stomach pain, get medical help right away. You might have an ectopic pregnancy.

Other than the above, there are no long-term side effects with taking an emergency contraceptive—even multiple times.

Report Side Effects

Plan B may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Plan B Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For emergency contraception:
    • For oral dosage form (Plan B One-Step® tablets):
      • Adults and teenagers—One tablet taken as soon as possible and not more than 72 hours (3 days) after unprotected sex or after failure of another birth control method.

Modifications

The following modifications (changes) should be kept in mind when using Plan B:

  • Severe allergic reaction: Avoid using Plan B if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.
  • Breastfeeding: While experts prefer non-hormonal birth control methods, progestin-only contraceptives—like levonorgestrel—are the treatment of choice while nursing. Based on currently available evidence, levonorgestrel isn't linked to adverse effects in nursing babies. In fact, you can nurse your baby again after three to four hours of taking Plan B.
  • Administration modifications: If you threw up within two hours of taking Plan B, you might need to take another dose. If you have questions, contact your pharmacist or healthcare provider.

Missed Dose

Plan B is typically taken as a one-time dose as soon as possible within three days of unsafe sex or suspected birth control failure. If you missed your chance to take Plan B within the three-day period, Plan B might still work within a five-day window. Your risk of pregnancy, however, is more likely.

If you threw up within two hours of taking Plan B, this is potentially a missed dose. Therefore, consider taking another Plan B dose. If you have any questions, talk with your pharmacist or healthcare provider.

Overdose: What Happens If I Take Too Much Plan B?

Generally, Plan B is not taken more than once unless you throw up within two hours of taking this medication.

If you accidentally take too many Plan B tablets, you might experience symptoms of nausea and vomiting. Contact the Poison Control Center for assistance. If you have life-threatening side effects, get medical help right away.

What Happens If I Overdose on Plan B?

If you think you or someone else may have overdosed on Plan B, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Plan B, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check you closely to make sure this medicine is working properly and does not cause unwanted effects.

Although you are using this medicine to prevent pregnancy, you should know that using this medicine while you are pregnant could harm the unborn baby. Your doctor may give you a pregnancy test before you start using this medicine to make sure you are not pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.

Call your doctor right away if you have severe lower abdominal or stomach pain 3 to 5 weeks after taking this medicine. You may have a pregnancy outside of the uterus (womb), which is called an ectopic pregnancy. An ectopic pregnancy can be a serious and life-threatening condition. It can also cause problems that may make it harder for you to become pregnant in the future.

You may have some blood spotting a few days after taking this medicine. If the bleeding continues for more than 1 week, check with your doctor right away.

This medicine may make your next monthly period later than expected by a few days. If your next period after taking this medicine is more than 1 week late, check with your doctor right away for a pregnancy test.

This medicine will not protect you from getting HIV/AIDS or other sexually transmitted infections. If this is a concern for you, talk with your doctor.

Your regular birth control method such as birth control pills or patch may not work as well while you are using this medicine. After using this medicine, you must use two forms of birth control. Use birth control pills or patch together with another form of birth control, such as a condom, diaphragm, or contraceptive foam or jelly, during any other times that you have sex in the same monthly period you used this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn’t Take Plan B?

If the following applies to you, avoid taking Plan B:

  • You suspect or know that you’re pregnant.
  • You have a severe allergic reaction to Plan B or its components (ingredients). Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.
  • You have a regular birth control method. Plan B isn’t meant to be used in this way.

What Other Medications Interact With Plan B?

There is limited information about interactions between Plan B and other medications. Since the body uses cytochrome P450 (CYP450) proteins—from the liver—to break down levonorgestrel (the main ingredient in Plan B), use caution with the following medications that influence these liver proteins.

The above medications encourage the CYP450 proteins to break down levonorgestrel quickly. With less levonorgestrel in the body, Plan B might not work well. 

Human immunodeficiency virus (HIV) medications—like efavirenz—can also lower the amount of levonorgestrel in the body.

This isn’t a complete list of possible medication interactions with Plan B. For more detailed information, speak with your pharmacist or healthcare provider about all the products you take, including plants/herbs, or supplements. Your pharmacist or healthcare provider can help determine if you need to take more Plan B tablets or make any other adjustments.

What Medications Are Similar?

There are many routine birth control methods available. However, in addition to Plan B, there are only three more emergency contraceptive options. All of the following choices are emergency contraceptives, but they’re not usually used together. If you have any questions, contact your pharmacist or healthcare provider.

Ella

Like Plan B, Ella (ulipristal) is a tablet. It’s taken as soon as possible within five days of unsafe sex or suspected birth control failure. Plan B and Ella are equally effective within a three-day window of this event. However, Ella is more effective than Plan B between the three- to five-day mark.

Unlike Plan B, Ella requires a prescription from a healthcare provider. You must also wait five days after taking Ella before starting a hormonal birth control—like an oral birth control pill or patch.

Copper Intrauterine Device

Paragard is a non-hormonal copper intrauterine device (IUD), the most effective emergency contraceptive. Within five days of unprotected sex or suspected birth control failure, your healthcare provider can place the IUD in your uterus. Afterward, the IUD can continue as a routine form of birth control for 10 years.

Yuzpe Regimen

For the Yuzpe regimen, you’ll take one dose of ethinyl estradiol (EE) 0.1 milligrams with 0.5 milligrams of levonorgestrel. After 12 hours, you’ll repeat a dose of this hormonal combination.

This emergency contraceptive method isn’t as effective as the other options. You might also experience more side effects—like nausea and vomiting—with the Yuzpe regimen.

Frequently Asked Questions

  • Is Plan B an abortion pill?

    Plan B isn’t an abortion pill. It only prevents a pregnancy from happening. If you’re already pregnant with a fertilized egg successfully attached to the uterus, Plan B won’t interfere with or end an established pregnancy.

  • Where is Plan B available?

    Plan B is available as an over-the-counter (OTC) product at local retail pharmacies.

  • How much does Plan B cost?

    Plan B usually costs between $40 to $50.
    However, since insurance might cover the costs of Plan B, you may request a prescription from your healthcare provider.
    Ask your healthcare provider or pharmacist about other options for cutting down costs. You may also get Plan B at little to no cost at a nearby Planned Parenthood health center, local health department, or other family planning clinics.

  • How do I know that Plan B worked?

    You won’t know that Plan B worked until your next menstrual period. After taking Plan B, it’s normal for your period to be a little late. However, if it’s been over a week later than expected, contact your healthcare provider to rule out pregnancy.

How Can I Stay Healthy While Taking Plan B?

If taken within three days of unprotected sex or suspected birth control failure, Plan B can lower your pregnancy risk. Take Plan B as soon as possible within this three-day window for better effectiveness.

After taking Plan B, you’re still at risk of becoming pregnant. Therefore, it’s essential to use a barrier birth control method—like a condom—at least until your next menstrual period. Using a condom can also protect you from sexually transmitted infections (STIs), while Plan B cannot. In addition to using condoms, you can get certain vaccines to prevent STIs. Also, consider getting STI testing

Since Plan B isn’t meant to be used as a routine birth control method, you can start or continue with a regular form of birth control after taking Plan B. With many available options, talk with your healthcare provider to find the best option for you—depending on costs, convenience, and other preferences.

After taking Plan B, it’s normal for your period to run a little late. However, if it’s been more than a week later than expected, reach out to your healthcare provider for a pregnancy test. Also, get medical help right away if you experience severe stomach pain.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Sedgh G, Singh S, Hussain R. Intended and unintended pregnancies worldwide in 2012 and recent trends. Stud Fam Plann. 2014 Sep;45(3):301-14. doi:10.1111/j.1728-4465.2014.00393.x

  3. The American College of Obstetricians and Gynecologists. Access to Contraception.

  4. Planned Parenthood. How often can you take the morning-after pill?

  5. Drugs and Lactation Database (LactMed). Oral Levonorgestrel.

  6. Centers for Disease Control. U.S. Selected Practice Recommendations for Contraceptive Use, 2016.

  7. MedlinePlus. Levonorgestrel.

  8. Emergency contraceptionPaediatr Child Health. 2003;8(3):181-192. doi:10.1093/pch/8.3.181

  9. Food and Drug Administration. Birth Control.

  10. Food and Drug Administration. Ella label.

  11. Planned Parenthood. What’s the Plan B morning-after pill?

By Ross Phan, PharmD, BCACP, BCGP, BCPS
Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.