• Saturday July 11,2020


5-fluorouracil is a cytostatic used in human medicine. The application is carried out as part of a holistic chemotherapy under medical supervision to treat so-called malignant ("malignant") tumors at various body sites. Due to the strong side effects, a strict pharmacy and prescription requirement exists within the European Union.

What is 5-fluorouracil?

The medical drug 5-fluorouracil (short: 5-FU) is often called fluorouracil (short: INN). Both names represent a heterocyclic organic compound based on a pyrimidine base. The active ingredient inhibits the growth of cells and is therefore counted to the drug group of cytostatics. 5-Fluorouracil is thus administered as part of holistic chemotherapy to treat malignant tumors.

Typically, 5-fluorouracil is used to treat breast cancer or colorectal cancer or tumors of the gastrointestinal tract. Furthermore, the use for the therapy of warts is conceivable in a lower dosage. In these cases, the active ingredient is processed into a cream intended for external use.

5-FU has been sold internationally since the 1960s and developed by the American chemist Charles Heidelberger. In chemistry and pharmacy the substance is described by the empirical formula C 4 - H 3 - F - N 2 - O 2, which corresponds to a mass of 130, 08 g / mol. At room temperature, 5-FU is present as a white powder. It is water-soluble and can be processed into an infusion solution.

Pharmacological effect on body and organs

5-fluorouracil is a member of the drug class of so-called antimetabolites. These are chemical compounds that inhibit the metabolization process of natural metabolites and therefore inhibit the physiological processes of the body.

From a chemical point of view, 5-fluorouracil is also similar to the pyrimidine analogues because of its structural comparability with the pyrimidine base uracil. This term can be subsumed by various drugs derived from the organic compound pyrimidine.

5-Fluorouracil inhibits thymidilate, an essential enzyme of pyrimidine biosynthesis. This prevents the conversion of dUMP (deoxyuridine monophosphate) into dTMP (deoxythymidine monophosphate), which in turn leads to inhibition of cell growth. In this way, 5-fluorouracil in particular succeeds in preventing cells from proliferating at a high rate of division.

Medical application & use for treatment & prevention

An indication of 5-fluorouracil exists both alone and in combination with other preparations. The administration of the drug folinic acid has been proven to increase the cytotoxic effect of 5-FU again (so-called FOLFIRI or FOLFOX scheme).

In general, 5-fluorouracil is considered to be a highly effective drug that has a broad spectrum of efficacy. Therefore, the potential application area is particularly large. An award of 5-fluorouracil is indicated in particular for various tumor diseases. Especially malignant tumors of the gastrointestinal tract (gastrointestinal tract) such as colorectal carcinoma, an anal carcinoma or an esophageal carcinoma can be treated.

In addition, there is also an indication for the treatment of malignant tumors in the head and neck (squamous cell carcinoma). Frequently, 5-FU is also used in the context of chemotherapy for the treatment of breast cancer (breast cancer).

If 5-fluorouracil is used to treat carcinomas, it will be given intravenously as part of chemotherapy. The drug itself is issued exclusively to physicians and distributed as a powder for solution for infusion. There is a strict prescription and pharmacy duty within the European Union, so that the independent acquisition by the patient is excluded.

In addition to cancer therapy, 5-FU is also used in reduced concentrations in creams intended for the topical treatment of warts.

Risks & Side Effects

Since 5-FU is a highly effective cytostatic drug, there are many risks and side effects. Also, immense interactions with other drugs must be considered. The use of 5-fluorouracil should be avoided altogether if there is a contraindication. This is always the case when there are circumstances that would lead to unmanageable risks and therefore make a treatment with the drug from a medical point of view seem unreasonable (counter-notification). Such circumstances exist if intolerances or allergies are known.

In addition, 5-fluorouracil is contraindicated if severe changes in the blood count occur, disorders of bone marrow function or blood formation are present. Even patients suffering from acute infections or severe liver dysfunction should not take 5-FU. During pregnancy and lactation, 5-fluorouracil can lead to significant malformations, so any contact with the substance should be avoided.

Common side effects that may occur during or shortly after taking 5-fluorouracil include gastrointestinal disorders. These express themselves by strong nausea, diarrhea (diarrhea), vomiting or mucositis. In addition, disorders of the hematopoietic system are conceivable. Especially bone marrow depression can be attributed to the intake of 5-fluorouracil. In some cases, it may also come after the ingestion of a hand-foot syndrome.

The extent of the respective side effects depends on the individual case. In particular, the dose administered in each case is essential for the intensity of the complaints.

Interactions are conceivable, above all, with various antivirals. The active substance brivudine (Zostex) can cause severe interactions. The same is the case with concomitant use of 5-FU prodrugs such as capecitabine. A safety margin of at least four weeks should be respected.

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