Leucovorin injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall; cancer chemotherapy medication) when methotrexate is used to to treat certain types of cancer. Leucovorin injection is used to treat people who have accidentally received an overdose of methotrexate or similar medications. Leucovorin injection is also used to treat anemia (low level of red blood cells) caused by low levels of folic acid in the body. Leucovorin injection is also used with 5-fluorouracil (a chemotherapy medication) to treat colorectal cancer (cancer that begins in the large intestine). Leucovorin injection is in a class of medications called folic acid analogs. It treats people who are receiving methotrexate by protecting healthy cells from the effects of methotrexate. It treats anemia by supplying folic acid that is needed for red blood cell formation. It treats colorectal cancer by increasing the effects of 5-fluorouracil.

Leucovorin injection comes as a solution (liquid) and a powder to be mixed with liquid and injected intravenously (into a vein) or into a muscle. When leucovorin injection is used to prevent harmful effects of methotrexate or to treat an overdose of methotrexate or a similar medication, it is usually given every 6 hours until laboratory tests show it is no longer needed. When leucovorin injection is used to treat anemia, it is usually given once a day. When leucovorin injection is used to treat colorectal cancer, it is usually given once a day for five days as part of a treatment that may be repeated once every 4 to 5 weeks.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before receiving leucovorin injection,

• tell your doctor and pharmacist if you are allergic to leucovorin, levoleucovorin, folic acid (Folicet, in multi-vitamins), or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: certain medications for seizures such as phenobarbital, phenytoin (Dilantin), and primidone (Mysoline); and trimethoprim-sulfamethoxazole (Bactrim, Septra). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have anemia (low number of red blood cells) caused by lack of vitamin B12 or inability to absorb vitamin B12. Your doctor will not prescribe leucovorin injection to treat this type of anemia.
• tell your doctor if you have or have ever had a buildup of fluid in the chest cavity or the stomach area, cancer that has spread to your brain or nervous system, or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving leucovorin injection, call your doctor.

Unless your doctor tells you otherwise, continue your normal diet.

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• seizures
• fainting
• diarrhea
• rash
• hives
• itching
• difficulty breathing or swallowing

Leucovorin injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body’s response to leucovorin injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

• Wellcovorin^® I.V.^¶

• citrovorum factor
• folinic acid
• 5-formyl tetrahydrofolate