ANTINEOPLASTIC AGENTS

• Antineoplastic drugs are cytotoxic by virtue of their ability to interfere with normal cellular growth by a variety of mechanisms preventing cell division & proliferation

• They have a particularly affinity for dividing cells:

1) Malignancies that respond best to chemotherapy are the more rapidly growing ones

2) Principle adverse reactions involve body’s cells that are rapidly dividing [bone marrow, hair follicles, mucous membranes]

• Alkylating Agents eg Cyclophosphamide

- Alkylate [form linkages] with nucleic acids thereby interefering with DNA synthesis

• Antimetabolites eg Methotrexate, 5-fluorouracil (5-FU)

- Exert cytotoxic activity by virtue of structual similarity to metabolites required by cells for normal growth & metabolism

- Include analogues of folic acid, pyrimidine and purine

• Antitumour antibiotics eg Bleomycin

- Isolated from fungi streptomyces

- Bind selectively with DNA, forming complexes which block formation of DNA dependent RNA

• Mitotic inhibitors eg Vinblastin

- block cell mitosis