Plan B One-Step is a morning-after pill (emergency contraceptive pill) used to prevent pregnancy after unprotected sex or failure of other forms of birth control (such as condom breakage, or a missed dose of birth control pills). The Plan B pill works by temporarily delaying the release of an egg from the ovary (ovulation), so it helps to prevent pregnancy before it starts.  Plan B (levonorgestrel, 1.5 mg) should be taken within 72 hours of unprotected sex or birth control failure, and the sooner it is taken, the better it works. 

Any person, regardless of age or gender can purchase Plan B One-Step right off the shelf without a prescription or ID requirement at all major retailers in the U.S.

The Plan B pill is a backup method of preventing pregnancy and should not be used as a regular form of birth control. Talk with your doctor or healthcare professional about the many forms of birth control available.

How effective is Plan B?

In a clinical trial Plan B was effective at lowering the chance of becoming pregnant from 8% on average to 1.1%, after a single act of mid-cycle unprotected sex if it was taken correctly within 72 hours after unprotected sex. In a review of clinical trials Plan B was shown to have an efficiency rate of 89% when taken correctly, as directed.

What is the difference between Plan B and Plan B One-Step?

• Plan B One-Step contains one levonorgestrel 1.5 mg tablet and is available over-the-counter without prescription
• Plan B contained two levonorgestrel 0.75 mg tablets and is now discontinued.

Do not use this medicine if you are already pregnant. Levonorgestrel will not terminate a pregnancy that has already begun (the fertilized egg has attached to the uterus).

Ask a doctor or pharmacist before taking levonorgestrel if you regularly use medication for seizures, tuberculosis, or HIV/AIDS. Certain medications can make levonorgestrel less effective as an emergency form of contraception.

Take Plan B One-Step exactly as directed on the label, or as prescribed by your doctor or health professional.

Plan B One-Step is one tablet that is taken once.  It must be taken as soon as possible and no later than 72 hours (3 days) after unprotected sex.  The sooner the tablet is taken, the better it works.

Call your doctor right away if you vomit within 2 hours after taking this medicine, as you may need to take another tablet.

Visit your doctor within 3 weeks after taking this medicine. A doctor should confirm that you are not pregnant and that this medicine has not caused any harmful effects.

If your period is late by 1 week or longer after the expected date, you may be pregnant. Get a pregnancy test and contact your doctor if you are pregnant. Levonorgestrel will not terminate a pregnancy if the fertilized egg has attached to the uterus.

You should not use Plan B One-Step if you are allergic to levonorgestrel or any of the ingredients in this medicine. A list of all ingredients is near the bottom of this page.

Pregnancy

Do not use this medicine if you are already pregnant. This medicine will not terminate a pregnancy that has already begun (the fertilized egg has attached to the uterus).

Breastfeeding

Levonorgestrel may slow breast milk production. Tell your doctor if you are breastfeeding.

Since this medicine is used as a single dose, it does not have a daily dosing schedule.

Because this medicine is supplied as a single tablet in an exact strength, an overdose is unlikely to occur when this medicine is used as directed. Do not take more than one tablet at the same time.

This medicine will not protect you from sexually transmitted diseases--including HIV and AIDS. Using a condom is the only way to protect yourself from these diseases. Avoid having unprotected sex.

Serious Plan B One-Step side effects:

Allergic reaction: Get emergency medical help if you have signs of an allergic reaction to this medicines. Symptoms may include hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Tubal (ectopic) pregnancy: Call your doctor or seek emergency medical help if you have severe pain in your lower stomach or side. This could be a sign of a tubal pregnancy (a pregnancy that implants in the fallopian tube instead of the uterus). A tubal pregnancy is a medical emergency that needs medical treatment immediately.

Common Plan B One-Step side effects may include:

• stomach pain;
• breast pain or tenderness;
• nausea, vomiting, diarrhea;
• headache, dizziness;
• feeling tired; or
• changes in your menstrual periods, including your period being earlier or later than expected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Certain other medications can make levonorgestrel less effective, which may result in pregnancy. Do not take this medicine without telling your doctor or pharmacist that you are using any of the following medications:

• efavirenz (Atripla, Sustiva);
• rifampin (Rifadin, Rifater, Rifamate, IsonaRif, Rimactane); or
• seizure medication--carbamazepine, felbamate, fosphenytoin, oxcarbazepine phenobarbital, phenytoin, primidone.
•  Bosentan
• Griseofulvin
• topiramate

This list is not complete. Other drugs may interact with levonorgestrel, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide, to check for interactions with Plan B click on the link below.