Chemotherapy drugs can be classified into various groups that are based on features such as their chemical structure, how they work, and their relationship to other drugs. In some cases, some of the chemotherapy drugs act in various ways and therefore, they may belong to more than a single group (Thomas, 2009).

Alkylating Agents

These represent the oldest chemotherapy drugs which act by destroying the deoxyribonucleic acid (DNA). They damage it by triggering cross-linking of DNA threads, creating abnormal base coupling, initiate DNA threats breakage and all this inhibits the cell from dividing. They kill the cell in several and multiple stages of the cell cycle and this makes them effective for slow-growing cancers. Some examples of alkylating agents include cyclophosphamide, busulfan, chlorambucil, and also thiotepa (DeAngelis & Poster, 2008, p. 453).

Antimetabolites

Antimetabolites hamper with the normal metabolic pathways including the ones that are required for making new DNA. They work by replacing the regular building blocks of the DNA and this causes damage during S stage. These agents are efficient in treatment of conditions such as leukemia, breast cancer, intestinal cancer and also ovary cancer. They include drugs like 5-fluorouracil (5-FU), capecitabine, clofarabine and floxuridine (Warrell, Cox & Firth, 2003, p. 261).

Anthracyclines

These are anti-tumor antibiotics that damage the enzymes responsible for DNA replication. They are mainly natural sources class of chemotherapeutics that function by creation of free oxygen radicals. The anthracyclines prevent the enzyme topoisomerase from forming because it is the one responsible for DNA repair, replication and also transcription. The drugs work in all cell stages of the cell cycle and they include idarubicin, mitoxantrone, and idarubicin (López-Miranda, Herradón, González & Martín, 2010).

Camptothecins/ Topoisomerase Inhibitors

These agents work by preventing the creation of topoisomerase enzyme that is needed in on-going DNA synthesis. They are anti-tumor antibiotics for both liquid and solid tumors and they are naturally occurring alkaloid. The drugs in this category include etoposide, topotecan, teniposide and mitoxantrone (Thomas, 2009, p. 248).

Vinca Alkaloids

These are plant alkaloids that inhibit or prevent the creation of mitotic shaft apparatus. Vinca alkaloids hinder mitosis or prevent enzymes from creating proteins that are required during cell reproduction. The hindering of mitosis means that these drugs become active at the M phase of the cell cycle. There is a risk of suffering peripheral nerve damage when using these drugs. They include taxanes, epothilones, and estramustine (Thomas, 2009, p. 248).

Platinums

The natural metal products have also been known to assist in cancer chemotherapy since they work by cross-linking the DNA sub-units. The crosslinking can occur amongst one thread or two threads of DNA and this prevents DNA combination, function and transcription. They work during any phase of the cell cycle and this makes them good for lung as well as testicular cancer and they include carboplatin and oxaliplatin (Warrell, Cox & Firth, 2003, p. 246).

Similarities between the Drugs

In essence, some of the agents such as Alkylating Agents and Platinums work in the same way by triggering cross-linking DNA. This process causes abnormal coupling and combination of DNA that destroys the cancer cells. Camptothecins and Vinca Alkaloids hinder the production of enzymes that trigger the creation of DNA. In most cases, most of these agents have serious side effects to the body after the treatment begins (Iqbal & Leichman, 2009).

Conclusion

The chemotherapy cancer drugs function differently based on their chemical composition, their functions, and how they act with other drugs. The major categories of cancer chemotherapy drugs include alkylating agents, antimetabolites, Anthracyclines, Topoisomerase Inhibitors, Vinca Alkaloids and Platinums. In essence, some of these drugs function in the same way while others work differently to kill cancer cells.

Bibliography

DeAngelis, L, & Poster, J 2008. Neurologic Complications of Cancer. Oxford, UK: Oxford University Press.

Iqbal, S, & Leichman, L 2009, ‘Chapter 28: Principles of Chemotherapy’, Esophageal Cancer: Principles & Practice pp. 243-253 n.p.: Academic Search Premier, EBSCOhost, viewed 13 May 2014.

López-Miranda, V, Herradón, E, González, C, & Martín, M 2010, ‘Vascular Toxicity of Chemotherapeutic Agents’, Current Vascular Pharmacology, 8, 5, pp. 692-700, Academic Search Premier, EBSCOhost, viewed 13 May 2014.

Thomas, C 2009. Esophageal Cancer: Principles and Practice. New York: Demos Medical Publishing.

Warrell, D, Cox, M, & Firth, J 2003. Oxford Textbook of Medicine, Volume 1. Oxford, UK: Oxford University Press.