Medications Used for Chemotherapy

Chemotherapy is the primary treatment method for cancer. It involves the use of different drugs to kill cancer cells, which grow much more rapidly than normal cells. Chemotherapy may be used before cancer surgery (to make it easier to remove the cancer) or in combination with radiotherapy to enhance the effects of radiotherapy. The type of medication used in chemotherapy depends on the type and stage of cancer, as well as the patient's overall health and medical history. Among the several different types of chemotherapy drugs are: alkylating agents, antimetabolites, anti-tumor antibiotics, topoisomerase inhibitors, mitotic inhibitors and corticosteroids.

Alkylating Agents

• Drugs that impede the reproduction of cancer cells by making changes in the DNA (deoxyribonucleic acid) are called alkylating agents. These drugs affect cancer cells regardless of their phase. The major side effect of alkylating agents is damage to the bone marrow in the long term. People who use high doses of alkylating agents are at a high risk of developing leukemia. Some examples of alkylating agents include: nitrogen mustards (such as chlorambucil), nitrosoureas (such as carmustine), alkyl sulfonates (such as busulfan), triazines (such as dacarbazine), and ethylenimines (such as thiotepa).

Antimetabolites

• Antimetabolites modify the DNA and RNA (ribonucleic acid) to prevent the growth of cancer cells. Some examples of antimetabolites include: 5-fluorouracil, 6-mercaptopurine, cytarabine, fludarabine, gemcitabine, methotrexate and pemetrexed.

Anti-tumor Antibiotics

• Anti-tumor antibiotics that impede the enzymes responsible for the duplication of DNA are called anthracyclines. These drugs, like alkylating agents, are not phase-specific. Since high doses of anthracyclines may cause permanent heart damage, there is a limit on how much of the drug a person can use in a lifetime. Some examples of anthracyclines are: doxorubicin, epirubicin and idarubicin. Other examples of anti-tumor antibiotics include: actinomycin-D, bleomycin, mitoxantrone and mitomycin-C.

Topoisomerase Inhibitors

• Topoisomerases are enzymes that take apart the DNA strands, so they can be replicated. Topoisomerase inhibitors impede the topoisomerase enzymes and prevent duplication of DNA. These drugs may also cause a type of cancer called myelogenous leukemia. Some examples of topoisomerase inhibitors include: topotecan, irinotecan, etoposide, and teniposide.

Mitotic Inhibitors

• Mitotic inhibitors prevent the production of proteins that are essential for reproduction of cells. Mitotic inhibitors may cause minor damage to nerve cells. Some examples of these drugs are: taxanes (such as paclitaxel), epothilones (such as ixabepilone), vinca alkaloids (such as vinblastine), and estramustines (such as Emcyt).

Corticosteroids

• Corticosteroids are used to kill cancer cells and also to prevent chemotherapy-induced nausea. They are also used prior to chemotherapy to prevent any allergic reactions to chemotherapy drugs. Examples of corticosteroids include dexamethasone, prednisone and methylprednisolone.