| Noun | 1. | cytotoxic drug - any drug that has a toxic effect on cells; commonly used in chemotherapy to inhibit the proliferation of cancerous cellsantineoplastic, antineoplastic drug, cancer drug - any of several drugs that control or kill neoplastic cells; used in chemotherapy to kill cancer cells; all have unpleasant side effects that may include nausea and vomiting and hair loss and suppression of bone marrow function | |