ANTINEOPLASTIC AGENTS

The chemotherapeutic agents which are used to treat cancer are called antineoplastic agents. Cancer is a tumour produced due to abnormal growth of some cells. It is not clear how cancer is caused. Generally cancer is produced by heavy smoking, constant physical irritation of any tissue of the body, chewing of tobacco. exposure to x-rays, ultraviolet rays and other ionizing radiation and by viruses. 

Antineoplastic agents, also known as cytotoxic agents, are used to treat malignant disease when surgery or radiotherapy is not possible or remained ineffective. They are used as an adjunct to surgery or radiotherapy and in the treatment of leukaemia. Direct contact of cytotoxic agents may cause irritation of the skin, eyes and mucous membranes.

The two main types of antineoplastic drugs are the alkylating agents and the antimetabolites. Nitrogen mustards, ethyleneimine compounds and alkyl sulphonates are the main alkylating agents. The antimetabolites include some enzymes.

Majority of antineoplastic agents act by interfering with cell division. No cytotoxic agent has complete tumor selectivity and most will damage all rapidly dividing cells. Major adverse effects include bone marrow depression, alopecia, nausea, vOmiting, stomatitis, dysphagia and diarrhoea. Hepatotoxicity, metabolic abnormalities, urinary tract, cardiac and nervous system toxicities are also reported with these drugs. Menstrual irregularities and premature menopause occur with long-term use of alkylating agents.

Combinations of antineoplastics are superior to single drug therapy leading to higher response rates and increased duration of remissions. Improved response may be due to use of agents which work by different mechanisms..