Comprehensive Nursing Pharmacology Q 27
The chemotherapeutic DNA alkylating agents such as nitrogen mustards are effective because they:
A. Cross-link DNA strands with covalent bonds between alkyl groups on the drug and guanine bases on DNA.
B. Have few, if any, side effects.
C. Are used to treat multiple types of cancer.
D. Are cell cycle-specific agents.
Correct Answer: A. Cross-link DNA strands with covalent bonds between alkyl groups on the drug and guanine bases on DNA.
Alkylating agents are highly reactive chemicals that introduce alkyl radicals into biologically active molecules and thereby prevent their proper functioning, replication, and transcription. Nitrogen mustard derivatives form one of the major classes of anti-cancer agents in the USFDA approved drugs list. These are polyfunctional alkylating agents which are distinguished by a unique mechanism of adduct formation with DNA involving cross-linking between guanine N-7 of one strand of DNA with the other. The generated cross-linking is irreversible and leads to cell apoptosis. Hence it is of great interest to explore this class of anticancer alkylating agents.
Option B: Alkylating agents have numerous side effects including alopecia, nausea, vomiting, and myelosuppression. Typically, signs and symptoms of nitrogen mustard exposure do not occur immediately. Depending on the severity of the exposure, symptoms may not occur for several hours.
Option C: Nitrogen mustards have a broad spectrum of activity against chronic lymphocytic leukemia, non-Hodgkin’s lymphoma, and breast and ovarian cancer, but they are effective chemotherapeutic agents because of DNA cross-linkage. HN-2 was designed as a military agent but was later used in cancer treatment. Other treatment agents now have replaced it.
Option D: Alkylating agents are noncell cycle-specific agents. Nitrogen mustards come in different forms that can smell fishy, musty, soapy, or fruity. They can be in the form of an oily-textured liquid, a vapor (the gaseous form of a liquid), or a solid. Nitrogen mustards are liquids at normal room temperature (70ºF).