What Is 5FU?
5FU, short for fluorouracil, is a chemotherapy medication that interferes with the growth of cancer cells. It is one of the most widely used drugs in oncology and forms the backbone of treatment for several common cancers. Knowing what 5FU is, how it is given, and what to expect helps patients prepare for treatment.
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How 5FU Works
5FU belongs to a class of drugs called antimetabolites. It mimics a building block of RNA, which disrupts the cell division process. Cancer cells that rapidly divide are most affected, which is why the drug is effective against fast-growing tumors.
Common Uses
Oncologists prescribe 5FU for a range of cancers, most often colorectal cancer, where it is a standard part of treatment regimens. It is also used for breast cancer, stomach cancer, pancreatic cancer, and certain head and neck cancers. The drug may be given alone or combined with other chemotherapy agents, depending on the cancer type and stage.
How It Is Administered
5FU is typically delivered as an intravenous infusion in a clinic or hospital. In some cases, a continuous infusion pump may be used over several days. The schedule and dosage depend on the treatment protocol, the patient's overall health, and how the body responds to the drug.
Side Effects and Monitoring
Because 5FU affects fast-growing healthy cells as well, side effects can include fatigue, mouth sores, diarrhea, and low blood counts. Hand-foot syndrome, where the palms and soles become red and painful, is also possible. Blood tests are done regularly to monitor for serious toxicities, and doses may be adjusted if side effects become severe.
What Patients Should Know
Before starting 5FU, patients should discuss their full medical history with the care team, including any heart, kidney, or liver conditions. The drug can interact with other medications, and alcohol may worsen certain side effects. Staying hydrated, reporting new symptoms early, and following the scheduled monitoring plan help make treatment as safe and effective as possible.