5-fluorouracil

5-fluorouracil is a cytostatic that is used in human medicine. It is used as part of holistic chemotherapy under medical supervision in order to treat so-called malignant ("malignant") tumors on various parts of the body. Due to the strong side effects, there is a strict pharmacy and prescription requirement within the European Union.

What is 5-fluorouracil?

The medicinal substance 5-fluorouracil (short: 5-FU) is often too Fluorouracil (short: INN) called. Both names stand for a heterocyclic organic compound that is based on a pyrimidine. The active ingredient inhibits the growth of cells and is therefore included in the cytostatic drug group. 5-fluorouracil is therefore administered as part of holistic chemotherapy to treat malignant tumors.

5-Fluorouracil is commonly used to treat breast cancer, colorectal cancer or tumors of the gastrointestinal tract. It is also conceivable to use a lower dose for treating warts. In these cases, the active ingredient is processed into a cream that is 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 moral mass of approx. 130.08 g / mol. At room temperature, 5-FU is a white powder. It is water-soluble and can be processed into an infusion solution.

Pharmacological effect on the body and organs

5-Fluorouracil is a member of the class of active ingredients known as antimetabolites. These are chemical compounds that inhibit the metabolism process of natural metabolites and therefore have an inhibiting effect on 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 used to subsume various drugs derived from the organic compound pyrimidine.

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

Medical application & use for treatment & prevention

There is an indication for 5-fluorouracil both alone and in combination with other preparations. Administration with the medicinal substance folinic acid has proven to be effective in increasing the cytotoxic effect of 5-FU even further (so-called FOLFIRI or FOLFOX scheme).

In general, 5-fluorouracil is a highly effective drug that has a broad spectrum of effectiveness. That is why the potential area of ​​application is particularly large. The allocation of 5-fluorouracil is particularly indicated for various tumor diseases. Above all, malignant tumors of the gastrointestinal tract (gastrointestinal tract) such as colorectal carcinoma, anal carcinoma or esophageal carcinoma can be treated.

There is also an indication for the treatment of malignant tumors in the head and neck area (squamous cell carcinoma). Often, 5-FU is also used as part of chemotherapy for the treatment of breast cancer (breast cancer).

If 5-fluorouracil is used to treat carcinomas, it is administered intravenously as part of chemotherapy. The drug itself is issued exclusively to doctors and sold as a powder for the preparation of a solution for infusion. There is a strict prescription and pharmacy requirement within the European Union, so that the patient cannot purchase it independently.

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 agent, there are numerous risks and side effects. Immense interactions with other medicinal substances must also be taken into account. The use of 5-fluorouracil must be stopped entirely if there is a contraindication. This is always the case when there are circumstances that would lead to incalculable risks and therefore make treatment with the active ingredient appear unreasonable from a medical point of view (contraindication). Such circumstances exist, inter alia, if intolerance or allergies are known.

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

The most common undesirable side effects that can occur during or shortly after taking 5-fluorouracil include gastrointestinal discomfort. This manifests itself as severe nausea, diarrhea, vomiting or mucositis. In addition, disorders of the blood formation system are also conceivable. Bone marrow depression in particular can be attributed to taking 5-fluorouracil. In some cases hand-foot syndrome may also develop after ingestion.

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

Interactions are especially conceivable with various antivirals. The active ingredient brivudine (Zostex) can cause severe interactions. The same is the case with the simultaneous use of 5-FU prodrugs such as capecitabine. There should be a safety margin of at least four weeks between the intake.