Tacrolism is an immunosuppressive drug used in human medicine to treat organ transplant rejection. It acts on certain cells in the immune system that are responsible for these reactions. Tacrolism is given in capsule form or intravenously. The drug is also available as an ointment and in this form can also be used to treat severe atopic dermatitis. However, the side effects are numerous. Headache, nausea, vomiting, diarrhea, and decreased kidney function are particularly common.
What is tacrolism?
Tacrolimus is an active ingredient that belongs to the group of drugs called macrolides. Macrolides are antibiotic drugs that inhibit the multiplication and growth of bacteria. Tacrolimus was isolated from a soil-borne bacterial genus called Streptomyces. It has an extremely potent immunosuppressive effect. The patent for this compound, which is significant for human medicine, belongs to a Japanese pharmaceutical company.
Pharmacological action
Tacrolism has a potent immunosuppressive effect. Immunosuppressive agents suppress the normal response and function of a person’s immune system. They are used when the immune system suppresses medically intended processes too tightly. This includes, for example, attacking organs foreign to the body in the course of a transplant. The exact processes that the drug sets in motion in the human organism have not yet been fully explained. Tacrolism can bind to certain proteins within cells. Particularly significant is the binding to the so-called chaperone proteins and the serotonin-threonine phosphatase calcineurin. In addition, signal transduction is inhibited in T cells, which belong to the lymphocytes. T cells have important tasks in the immune system. For example, they recognize antigens to which certain antibodies can bind. In addition, the transcription of certain proteins, known as interleukin 2 and 3, is reduced. During transcription, genetic hereditary information is transferred from DNA strands to RNA. This can ultimately be converted into mRNA and pass on the genetic information. Interleukins are messenger substances released by the body to act on the immune system. Interleukin 2 stimulates the production of more T-helper cells, while interleukin 3 promotes the growth of stem cells in the bone marrow. Tacrolism thus massively interferes with the immune system of the human body and inhibits its functions.
Medical application and use
The drug has a strong effect on the human body and therefore should be prescribed only under strict medical supervision. Tacrolism can be administered in capsule form or as a liquid into the vein. The latter form of administration is used rather rarely, as it correlates positively with anaphylactic reactions. The drug is administered in combination with corticosteroids. These agents are hormones produced in the body from cholesterol. However, they can also be produced synthetically. The so-called non-retarding capsules are usually taken twice a day. The sustained-release capsules are given once a day. They should be taken either fasting or two to three hours after food intake. In addition, the drug is on the market as an ointment. The activation of T lymphocytes, T helper cells and cytotoxic lymphocytes is inhibited by tacrolism. These are responsible for the rejection of transplanted organs. The main application of tacrolism is therefore the prevention of rejection of heart, liver and kidney transplants. In the first months after transplantation, it is often necessary to combine the therapy with other agents that inhibit the immune system. The ointment can be used to treat very severe forms of the skin disease neurodermatitis. For this purpose, prior therapy with glucocorticoids must have failed.
Risks and side effects
The side effects of the active ingredient tacrolism are very complex. Particularly commonly described adverse effects include nausea, high blood pressure, diarrhea, insomnia, headache, diabetes mellitus, tremor, hyperglycemia, and impaired renal function. In addition, immunosuppressive drugs increase the risk of infections and tumors. Tacrolism also has a toxic effect on nerves.Other side effects include confusion, agitation, dizziness, decreased urine production, indigestion, decreased appetite, anemia, fever, depression, convulsions, nerve pain, and carbohydrate metabolism disorders. Less commonly, migraines, speech disorders, dyslipidemia, fainting, heart muscle weakness, respiratory failure, spleen enlargement, and peritonitis occur. Tacrolism ointment may cause redness, a feeling of warmth, pain, itching, rashes, discomfort and inflammation at the site of application. Infestation of the treated areas of the body by herpes viruses and parasites is also possible. The side effects of application to the skin are much less than the risks associated with oral or intravenous administration of the drug.
