The drug vinblastine belongs to the group of chemotherapeutic agents. It is used to treat cancer.
What is vinblastine?
Vinblastine is also known in medicine as vinblastine sulfate or vincaleukoblastine. The chemotherapeutic agent is considered the best-known representative of the vinca alkaloids. Vinblastine represents an alkaloid of the pink catharanth. This plant is also called pink indoor evergreen or Madagascar evergreen and belongs to the genus of catharanths. Vinca alkaloids have the property of binding to the protein tubulin, which inhibits the formation of microtubules, which are bundles of filaments. In this way, cancer cells, which divide rapidly, are also affected. At room temperature, vinblastine exists as a yellow powder. The aromatic hydrocarbon molecule dissolves easily in water. In Europe, vinblastine has been approved since the early 1960s. In Germany, the drug is marketed under the trade name Velbe.
Pharmacologic Action
Vinblastine belongs to the cytostatics and is one of the anti-cancer drugs. In addition, it forms a mitosis inhibitor as it counteracts mitosis (division of cells). In the drugs it is present as vinblastine sulfate. The active substance is obtained from the pink catharanth. During the process of cell division, filamentous bundles (microtubules) are formed. These attract the duplicated genetic chromosomes to themselves and thus ensure the emergence of an independent cell. Vinblastine has effects similar to those of the gout drug colchicine and acts directly on the formation of the filament bundles. For this purpose, it is bound to the building material tubulin, which interrupts the process of filament production. In addition, already existing microtubules are dissolved by the vinblastine. The network that is normally formed to allow proper division of the duplicated genetic material during cell division also suffers. Furthermore, vinblastine is said to have a killing effect on cells that temporarily fail to proliferate. However, a disadvantage of the chemotherapeutic agent is that it also affects healthy cells, which in turn results in unpleasant side effects. However, due to their rapid ability to divide, the cancer cells are more affected than the healthy cells. The half-life of vinblastine is considered long, lasting up to 24 hours.
Medical application and use
In some cases, vinblastine is administered as a monopreparation. However, it is usually used in conjunction with other cytostatic drugs or radiation treatment as part of cancer treatment. The most important indications for vinca alkaloid include malignant tumors of the lymphatic system such as Hodgkin’s disease, specific tumors of the lymph glands such as non-Hodgkin’s lymphoma, recurrent breast cancer with metastases (daughter tumors), and advanced stage testicular cancer. Another area of application is Langerhans cell histiocytosis. This is a special form of bone marrow cancer. Other areas of application include Kaposi’s sarcoma, hairy cell leukemia, and chorionic carcinoma (cancer of the villi) when other cytostatic drugs have no effect. Vinblastine is administered as an intravenous injection. Usually, treatment takes place once a week. If the patient’s liver is working poorly, a lower dosage must be administered. Injection into the spinal canal should be avoided. There is a risk of adhesion of the meninges.
Risks and side effects
Adverse side effects may result from treatment with vinblastine. The vinca alkaloid causes damage to white blood cells (leukocytes), while red blood cells (erythrocytes) are less affected. However, because the bone marrow recovers quickly, the absence of leukocytes rarely results in febrile infections. Common side effects of the cytostatic drug include nausea, vomiting, the formation of vesicles on the skin as well as in the mouth, a lack of platelets, constipation, bowel obstruction, nerve insensitivity, bone marrow dysfunction, anemia (anemia), bleeding from the rectum, bloody bowel inflammation, and refusal of food. In addition, patients often suffer from hair loss. However, this does not occur completely.In some patients, the hair even grows back during vinblastine therapy. In some cases, pharyngitis, pain in the tumor area, a general feeling of illness, cramps, headaches, nerve inflammation, numbness, tinnitus, dizziness, cardiac arrhythmias, angina pectoris attacks or depression may also occur. In addition, even with proper dosage, there is a risk that the patient’s water balance may be derailed. If the patient suffers from hypersensitivity to vinblastine or other vinca alkaloids, therapy with the cytostatic drug must be withheld. This also applies to infections that are difficult to control, as well as a deficiency of white blood cells that is not caused by the cancer. A thorough risk-benefit assessment by the physician is required in the case of circulatory disorders of the coronary vessels, liver dysfunction, an attack of cancer cells on the bone marrow, as well as in elderly patients in whom a drop in blood pressure may increase. During pregnancy, vinblastine should be administered only if specifically instructed by a physician. Thus, changes in the genetic material occurred in animal studies. Therefore, there is a risk of malformations in the unborn child. For women and men of childbearing age, the use of safe contraceptive methods is recommended during vinblastine therapy. There is also a risk of permanent infertility due to the cytostatic drug. If vinblastine is given with other cancer-killing drugs, side effects may increase. If vinblastine is taken at the same time as the antifungal drug itraconazole, there is a risk of intestinal paralysis or nerve damage. In addition, permanent lung damage is within the realm of possibility from taking vinblastine and the anticancer drug mitomycin C at the same time.
