5-Fluorouracil/Leucovorin Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Leucovorin enhances the effects of fluorouracil, including the side effects.

What might happen:

You may experience more severe and/or prolonged side effects, such as diarrhea, and mouth inflammation/sores.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Leucovorin calcium US prescribing information. Bedford Laboratories September, 2008.
  • 2.Jansman FG, Jansen AJ, Coenen JL, de Graaf JC, Smit WM, Sleijfer DT, Brouwers JR. Assessing the clinical significance of drug interactions with fluorouracil in patients with colorectal cancer. Am J Health Syst Pharm 2005 Sep 1;62(17):1788-93.
  • 3.Figoli F, Chiarion Sileni V, Gulisano M, Maggian P, Fosser V. Leucovorin calcium enhancement of mucositis after continuous infusion fluorouracil and short infusion cisplatin. J Clin Oncol 1989 May;7(5):680-1.
  • 4.Grem JL, Shoemaker DD, Petrelli NJ, Douglass HO Jr. Severe and fatal toxic effects observed in treatment with high- and low-dose leucovorin plus 5-fluorouracil for colorectal carcinoma. Cancer Treat Rep 1987 Nov; 71(11):1122.
  • 5.Stein TA, Burns GP, Bailey B, Citron ML. 5-Fluorouracil pharmacokinetics in patients with metastatic colorectal carcinoma after high-dose leucovorin. Cancer Invest 1994;12(4):375-8.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.