Cytotoxic drugs are toxic to cells. They are commonly used in chemotherapy and to treat lupus and juvenile rheumatoid arthritis. Chemotherapy is a systemic type of treatment, which means it works on cells throughout the body and not just cells in one place. More than half of people who are diagnosed with cancer will receive chemotherapy at some point in their treatment. This article offers a brief overview of the cytotoxic drugs that are used in treating cancer. If you have any questions or concerns about the drugs you are taking, it is best to ask your physician.
Chemotherapy can be administered in a variety of ways. People most often think of intravenous infusion, but it also can also be delivered in pill form, by a simple injection or deposited into the spinal cord fluid or abdominal cavity, depending on the type of cancer and the individual.
Classes of Cytotoxic Drugs
There are many classes of cytotoxic drugs, each working in a specific way on cells. Alkylating drugs cause damage to DNA and prevent cells from replicating. They work in all phases of the cell cycle and are used in a wide variety of cancers. Drugs in this class include nitrogen mustards like Cytoxan and nitrosoureas. The platinum-based drugs like carboplatin and cisplatin occasionally are classified as alkylating agents because they behave in the same way.
Antimetabolites disrupt the DNA and RNA of cells, which prevents growth. Drugs in this category include capecitabine (known by the brand name Xeloda), gemcitabine (Gemzar) and 5-fluorouracil.
Anti-tumour antibiotics are a third group of cytotoxic drugs. Anthracyclines fall into this group. These drugs disrupt enzymes that are needed for replication of the DNA. A danger with anthracyclines is that in high doses, they can damage the heart, so monitoring is important. Doxorubicin (known by the brand name Adriamycin) and epirubicin are anthracyclines. Other anti-tumour antibiotics that are not anthracyclines include bleomycin and actinomycin-D.
Mitotic inhibitors are a class of drugs that disrupt mitosis, or cell division. They also prevent cells from replicating. Taxanes fall into this group, as do vinca alkaloids. Specific drugs that are mitotic inhibitors include paclitaxel (brand name Taxol) and vincristine (Oncovin).
There are other kinds of cytotoxic drugs, such as corticosteroids, or drugs that do not fit into any one category.
Other Cytotoxic Therapies
Targeted therapies are still systemic therapies, but rather than attack all multiplying cells as in chemotherapy, they attack only cancer cells. Hormone therapies are also used in treating cancer, such as breast cancer, uterine cancer and prostate cancer. Immunotherapy is a new kind of cytotoxic therapy. These drugs help the body's immune system to better attack cancerous cells. Immunotherapy is not the same as chemotherapy.
Cytotoxic drugs cause different side effects in different people. These can vary depending on the drugs used and dosage. Blood cells commonly are affected by these drugs. White blood cells aid the body in fighting infection, and chemotherapy suppresses white blood cells, making an individual more susceptible to illness. Platelets and red blood cells also are suppressed with chemotherapy, making the individual more prone to bruising and fatigue. Other side effects of cytotoxic drugs include nausea and vomiting, loss of hair, mouth sores and loss of appetite.
As with any treatment, if you are taking cytotoxic drugs, talk to your doctor about any other medications you might be taking, both prescription and over-the-counter. It is important to follow up with your doctor with appointments and tests and report any side effects that concern you.