Medically reviewed: January 11, 2018
What is React?
Levonorgestrel is a female hormone that can cause changes in your cervix, making it harder for sperm to reach the uterus and harder for a fertilized egg to attach to the uterus.
React may also be used for purposes not listed in this medication guide.
This medicine will not terminate pregnancy if the fertilized egg has already attached to the uterus.
Ask a doctor or pharmacist before taking levonorgestrel if you regularly use medication for seizures, tuberculosis, or HIV/AIDS. Certain other medicines can make levonorgestrel less effective.
Before taking this medicine
You should not use levonorgestrel if you are allergic to it.
Do not use this medicine if you are already pregnant. React 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.
React is not intended for use as a routine form of birth control and should not be used in this manner. Talk with your doctor about the many forms of birth control available.
Levonorgestrel may slow breast milk production. Tell your doctor if you are breast-feeding.
React is not approved for use by anyone younger than 17 years old.
How should I take React?
Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.
React must be taken as soon as possible after unprotected sex (no later than 72 hours afterward).
Call your doctor right away if you vomit within 2 hours after taking this medicine. Do not take a second dose without first asking your doctor.
Visit your doctor within 3 weeks after taking React. 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. React will not terminate pregnancy if the fertilized egg has attached to the uterus.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Since React is used as a single dose, it does not have a daily dosing schedule.
What happens if I overdose?
Because this medicine is supplied as a single tablet in an exact strength, an overdose is unlikely to occur when the levonorgestrel is used as directed. Do not take more than one tablet at the same time.
What should I avoid while taking React?
React side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
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.
Common side effects may include:
mild stomach pain;
breast pain or tenderness;
feeling tired; or
changes in your menstrual periods.
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.
See also: Side effects (in more detail)
What other drugs will affect React?
Certain other medications can make React less effective, which may result in pregnancy. Do not take levonorgestrel without telling your doctor or pharmacist that you are using any of the following medications:
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.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 3.01.
More about React (levonorgestrel)
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- Drug class: contraceptives