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Generic name: leucovorin (oral) [ LOO-koe-VOR-in ]
Dosage form: oral tablet (10 mg; 15 mg; 25 mg; 5 mg)
Drug class: Antidotes

Medically reviewed by on Jul 31, 2023. Written by Cerner Multum.

What is leucovorin?

Leucovorin is a form of folic acid. Folic acid helps your body produce and maintain new cells, and also helps prevent changes to DNA that may lead to cancer. Folic acid is present in many foods such as dried beans, peas, oranges, spinach, and others.

Leucovorin is used to reduce the side effects of large doses or accidental overdose of medications that can reduce the effects of folic acid in the body. This includes methotrexate (Rheumatrex), pyrimethamine (Daraprim), trimethoprim (Trimpex, Proloprim), and others.

Leucovorin may also be used for purposes not listed in this medication guide.

Leucovorin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

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.


You should not take leucovorin if you have pernicious anemia or other types of anemia caused by a lack of vitamin B12.

Before taking this medicine

You should not take leucovorin if you have pernicious anemia or other types of anemia caused by a lack of vitamin B12.

If possible before you receive leucovorin, tell your doctor if you have:

Also tell your doctor about all other medications you currently use. There are many other drugs that can interact with methotrexate and slow down your body's ability to process and eliminate the drug. This can affect how quickly methotrexate is able to leave your body, even with the help of leucovorin.

It is not known whether leucovorin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether leucovorin passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How should I take leucovorin?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

When treating an accidental overdose, leucovorin should be started as soon as possible for the best effect.

Leucovorin is usually given with other medications to help your kidneys remove methotrexate from your body. You may also be treated with IV fluids to keep you from getting dehydrated.

You will need frequent medical tests to help your doctor determine how long to treat you with leucovorin.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

An overdose of leucovorin is not likely to cause life-threatening symptoms. However, leucovorin overdose can make other medications less effective.

What should I avoid while taking leucovorin?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect leucovorin?

Tell your doctor about all your current medicines and any you start or stop using, especially:

This list is not complete. Other drugs may interact with leucovorin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

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.