Antimetabolites: Effects, Uses & Risks

Antimetabolites refer to chemical compounds that cause inhibition of the metabolism of natural metabolites. Due to similar chemical structures, they have multiple effects on all physiological processes by blocking certain enzymes. Antimetabolites are used, for example, in the form of immunosuppressants or cytostatics for cancer therapy.

What are antimetabolites?

Antimetabolites closely resemble natural metabolites in their chemical makeup. In human metabolism, this similarity causes them to take over all the tasks of the body’s own metabolites. The latter are completely displaced when they are used. This causes a blockage of vital metabolic processes in the body’s cells and ultimately leads to their death. In the meantime, so-called folic acid antagonists such as methotrexate and antagonists such as fluorouracil or cytarabine are mostly used. In cancer therapy for breast, gastric, colorectal, bone and pancreatic cancer as well as leukemia, antimetabolites are also used for palliative care. However, since antimetabolites also damage healthy body cells, there are almost always severe side effects in the course of treatment. These side effects then require further treatment to prevent patients from becoming too debilitated.

Pharmacologic effects on the body and organs

The various medications used in chemotherapy are called cytostatics. They are antimetabolites. Cytostatic drugs stop the cellular functions of the human body. These antimetabolites cause the growth of the malignant cancer cells to be inhibited. This then causes the tumors to recur, i.e. they regress. Normally, cell growth is subject to strict rules. Healthy body cells basically divide only as often as is necessary for tissue function and its maintenance. In malignant tumor cells, this mechanism in the cell cycle is overridden and the degenerate cells divide uncontrollably and without hindrance. This is how a tumor develops. Antimetabolites act exactly here, directly on the cancer cells. They are preferentially attacked. Thus, different processes are affected, which are important for the division of the cells. The cell division process is disturbed and the further growth of the cancer cells is hindered.

Medical application and use for treatment and prevention.

All antimetabolites insert themselves into the DNA of cancer cells like a false building block there when they multiply. In this way, they succeed in destroying the genetic information in the relevant regions. The malignant cells can thus no longer divide. The so-called folic acid antagonists belong to the cytostatic drugs, as do the purine and pyrimidine analogues. These drugs are usually administered to patients intravenously or with the aid of infusions, which are delivered in drop form. In this way, the antimetabolites are usually administered together with ordinary table salt. Meanwhile, it is also common to administer special medications in the form of tablets. Many of these antimetabolites are highly toxic, so a wide variety of precautions must be taken when administering them. These include, for example, the use of mouth guards and gloves.

Risks and side effects

Most antimetabolites exhibit the same side effects because, like all cytostatic drugs, they prevent unnaturally proliferating malignant body cells from growing. Unfortunately, this also affects the healthy cells. Since the so-called degenerated cells have their origin in healthy cells, the therapy can basically not be targeted. All cells that grow naturally are then also affected by the effects of the treatment. These are mainly those responsible for blood formation. But hair growth and mucous membranes are also attacked. Furthermore, treatment with antimetabolites often leads to vomiting and nausea as well as a general feeling of illness. In the case of blood, the leukocytes and thrombocytes are primarily affected. After about two weeks, the number of these blood cells has decreased to such an extent that the immune system functions only to a limited extent. This makes the patient very susceptible to infections of all kinds. It is also possible that organ functions are impaired during treatment with antimetabolites.However, these side effects may depend largely on the type of medication.