alkylating agent /al″kilā′ting/ , any substance that contains an alkyl radical and is capable of replacing a free hydrogen atom in an organic compound, or one that acts by a similar mechanism. This type of chemical reaction results in interference with DNA synthesis and RNA transcription, which in turn results in interference with mitosis and cell division, especially in rapidly proliferating tissue, causing cell death. Alkylating agents are radiometric in that their action is similar to that of irradiation. The agents are useful in the treatment of cancer and are a common class of chemotherapy agents. Agents include cyclophosphamide, mechlorethamine, thiotepa, busulfan, carmustine, lomustine, streptozocin altretamine, and procarbazine. Adverse effects include myleosuppression, particularly anemia and nausea, vomiting, and alopecia.
