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Side Effects, Effectiveness & Warning


Plan B®

Emergency Contraceptive.

Because the unexpected happens.

Important Information About Plan B®, Birth Control & Sexually Transmitted Diseases

For additional information intended for healthcare professionals, please see enclosed Product Information for Plan B®.

What is Plan B®?

Plan B® is emergency contraception that helps prevent pregnancy after birth control failure or unprotected sex. It is a backup method of preventing pregnancy and should not be used as regular birth control.

What Plan B® is not.

Plan B® will not work if you are already pregnant and will not affect an existing pregnancy. Plan B® will not protect you from HIV infection (the virus that causes AIDS) and other sexually transmitted diseases (STDs).

When should I use Plan B®?

The sooner you take emergency contraception, the better it works. You should use Plan B® within 72 hours (3 days) after you have had unprotected sex.

Plan B® is a backup or emergency method of birth control you can use when:

  • your regular birth control was used incorrectly or failed
  • You did not use any birth control method

When not to use Plan B®?

Plan B® should not be used:

  • as a regular birth control method, because it’s not as effective as regular birth control.
  • if you are already pregnant, because it will not work.
  • if you are allergic to levonorgestrel or any other ingredients in Plan B®.

When should I talk to a doctor or pharmacist?

Ask a doctor or pharmacist before use if you are taking efavirenz (HIV medication) or rifampin (tuberculosis treatment) or medication for seizures (epilepsy). These medications may reduce the effectiveness of Plan B® and increase your chance of becoming pregnant. Your doctor may prescribe another form of emergency contraception that may not be affected by these medications.

How does Plan B® work?

Plan B® is two tablets with levonorgestrel, a hormone that has been used in many birth control pills for several decades. Plan B® contains a higher dose of levonorgestrel than birth control pills, but works in a similar way to prevent pregnancy. It works mainly by stopping the release of an egg from the ovary. It is possible that Plan B® may also work by preventing fertilization of an egg (the uniting of sperm with the egg) or by preventing attachment (implantation) to the uterus (womb).

How can I get the best results from Plan B®?

You have 72 hours (3 days) to try to prevent pregnancy after birth control failure or unprotected sex. The sooner you take Plan B®, the better it works. Take the first Plan B® tablet as soon as possible within 72 hours (3 days) after unprotected sex. Take the second tablet 12 hours later.

How effective is Plan B®?

If Plan B® is taken as directed, it can significantly decrease the chance that you will get pregnant. About 7 out of every 8 women who would have gotten pregnant will not become pregnant.

How will I know Plan B® worked?

You will know Plan B® has been effective when you get your next period, which should come at the expected time, or within a week of the expected time. If your period is delayed beyond 1 week, it is possible you may be pregnant. You should get a pregnancy test and follow up with your healthcare professional.

Will I experience any side effects?

  • some women may have changes in their period, such as a period that is heavier or lighter or a period that is early or late. If your period is more than a week late, you may be pregnant.
  • if you have severe abdominal pain, you may have an ectopic pregnancy, and should get immediate medical attention.
  • when used as directed, Plan B® is safe and effective. Side effects may include changes in your period, nausea, lower stomach (abdominal) pain, tiredness,
    headache, dizziness, and breast tenderness.
  • if you vomit within 2 hours of taking the medication, call a healthcare professional to find out if you should repeat the dose.

What are the directions for using Plan B®?

Women 17 years of age and older:

  • Take the first Plan B® tablet as soon as possible within 72 hours (3 days) after unprotected sex.
  • Take the second tablet 12 hours after you take the first tablet.
  • If you vomit within 2 hours of taking either dose of medication, call a healthcare professional to find out if you should repeat that dose.

Prescription only for women younger than age 17. If you are younger than 17, see a healthcare professional.

What if I still have questions about Plan B®?

If you have questions or need more information, call our toll-free number, 1-800330-1271 or ask a healthcare professional.

Other information

Keep out of reach of children:

In case of overdose, get medical help or contact a Poison Control Center right away at 1-800-222-1222.

Do not use if the blister seal is open.

Store at room temperature 20–25°C (68–77°F).

You may report side effects to FDA at 1-800-FDA-1088.

Active ingredient: levonorgestrel 0.75 mg in each tablet

Inactive ingredients: colloidal silicon dioxide, potato starch, gelatin, magnesium
stearate, talc, corn starch, lactose monohydrate


If you are sexually active, you should see a healthcare provider for routine checkups. Your healthcare provider will talk to you about and, if necessary, test you for sexually transmitted diseases, teach you about effective methods of routine birth control, and answer any other questions you may have.

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