Leucovorin: What to Expect, Side Effects, and More

Leucovorin, also called folinic acid, (brand names: Wellcovorin, Lederle Leucovorin) is typically given to people receiving the chemotherapy medicines fluorouracil or methotrexate.

Leucovorin recently came up in the news as President Trump and Health and Human Services Secretary Robert F. Kennedy Jr. touted it as a “treatment” for autism. The FDA has started the process to approve the drug for this use. 

While there have been a few studies showing that leucovorin provided some benefits for people with autism spectrum disorders, these studies have been very small. They’ve also used different doses of the medication and measured outcomes differently. Generally, the FDA approves drugs only after much larger, more rigorous trials. The move surprised experts, who described the approval as premature and stated that there isn’t enough evidence to support giving the medicine to people with autism.

See leucovorin prescribing information.

When given with fluorouracil, leucovorin enhances fluorouracil’s binding to thymidylate synthase, thereby increasing its efficacy. 

When given with methotrexate, leucovorin acts as a “rescue agent” — it reduces the side effects of methotrexate. Methotrexate kills both cancer and healthy cells by depleting their folic acid. Leucovorin helps to restore folic acid to healthy cells. 

Leucovorin can be given orally or intravenously through an IV or port. Dosage recommendations are dependent on the dose and route of the chemotherapy with which it is administered, but is typically taken every six hours for about a 24-hour period after the start of the chemotherapy infusion. 

Like almost all breast cancer medicines, leucovorin can cause side effects, some of them severe. Most of the side effects you experience will be due to the chemotherapy you have received, and not from the leucovorin, but are listed below. 

The most common side effects of leucovorin are:

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  mouth sores

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  vomiting

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  nausea

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  diarrhea

More serious side effects can occur, including:

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  seizures

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  fainting

Pregnant women shouldn’t take levoleucovorin as it’s given in combination with methotrexate or fluorouracil, which can cause embryo-fetal harm. 

Note: Leucovorin increases the toxicity of fluorouracil, which can worsen side effects.

The cost of leucovorin may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use. 

Note: Your insurance company may require you to get prior authorization before covering leucovorin. 

Learn more about financial assistance and medicine cost-lowering tips.