Levonorgestrel is used by women to prevent pregnancy after birth control failure (such as a broken condom) or unprotected sex. This medication is an emergency contraceptive and should not be used as a regular form of birth control. It is a progestin hormone that works mainly by preventing the release of an egg (ovulation) during your menstrual cycle. It also makes vaginal fluid thicker to help prevent sperm from reaching an egg (fertilization) and changes the lining of the uterus (womb) to prevent attachment of a fertilized egg.

Using this medication will not stop an existing pregnancy or protect you or your partner against sexually transmitted diseases (such as HIV, gonorrhea, chlamydia).

This medication may not work well in women over a certain weight (for example, greater than 164 pounds or 74 kilograms), or if you have used certain other medications within the past month. This effect can result in pregnancy. Talk to your doctor for more details and to see if this medication is right for you (see also Drug Interactions section).

Check the ingredients on the label even if you have used the product before. The manufacturer may have changed the ingredients. Also, products with similar names may contain different ingredients meant for different purposes. Taking the wrong product could harm you.

If you are taking the over-the-counter product to self-treat, read all directions on the product package before taking this medication. If you have any questions, talk to your pharmacist. If your doctor has prescribed this medication, take it as directed.

Take this medication by mouth as soon as possible after unprotected sex. Your instructions for use depend on the brand you take. Therefore, check the label on your brand and ask your doctor or pharmacist if you have any questions. Take as directed, usually 2 tablets at once; or take 1 tablet and then take the second tablet 12 hours after the first tablet. This medication may be taken with or without food. This medication works best when it is taken within 72 hours (3 days) after unprotected sex.

If you vomit within 2 hours of taking a dose of this medication, contact your doctor to ask if you need to repeat the dose.

After you take this medication, the time when your period comes and how much you bleed may change. Tell your doctor right away if your period is more than 7 days late. You may need to take a pregnancy test.