The National Cancer Institute defines an alkylating agent as a type of drug that is used to treat cancer by interfering with the cell's deoxyribonucleic acid (DNA) and inhibiting cancer growth. Let's explore the mechanism of action further. 

How Do Alkylating Agents Work?

Alkylating agents prevent cells from dividing and replicating by damaging the DNA. They work in all phases of the cell cycle and attack DNA in two ways.

1. Bifunctional alkylation: the drug becomes inserted between two base pairs in the DNA chain, forming an irreversible bond between them. It causes cytotoxic effects capable of destroying or poisoning cells.
2. Monofunctional alkylation: the drug reacts with just one strand of a pair, separating it from its partner and eventually causing it and its attached sugar to break away from the DNA molecule. It may eventually cause permanent cell damage.

Types and Examples of Alkylating Agents (Colvin, 2003)

Alkylating drugs are prescribed to treat a variety of cancers including brain, lung, breast, ovary, and testicular cancer; leukemia;lymphoma; Hodgkin disease; melanoma; multiple myeloma; and sarcoma (American Cancer Society, 2019). The following list includes categories and examples of alkylating agents but is not all inclusive.

• Nitrogen mustards: bendamustine, chlorambucil, cyclophosphamide, ifosfamide, mechlorethamine, melphalan
• Ethylenimines: altretamine, thiotepa
• Expoxides: dianhydrogalacititol, dibromodulcitol
• Alkyl sulfonates: busulfan, hepsulfan
• Nitrosoureas: carmustine, lomustine, streptozocin
• Triazenes: dacarbazine, temozolomide

Nursing Considerations (Colvin, 2003)

Alkylating agents may cause serious adverse effects, particularly at higher doses.

• Hematopoietic toxicity: suppression of granulocytes and platelets, immunosuppression
• Gastrointestinal toxicity: mucositis, stomatitis, esophagitis, diarrhea, nausea and vomiting
• Cardiac toxicity: rapid onset of severe heart failure
• Pulmonary damage: interstitial pneumonitis and fibrosis, nonproductive cough, dyspnea, tachypnea, and cyanosis
• Hepatotoxicity: jaundice, ascites, liver failure
• Renal toxicity: elevated serum creatinine, severe kidney failure
• Bladder toxicity: hemorrhagic cystitis, may progress to massive hemorrhage
• Gonadal damage
• Neurotoxicity: convulsions, drowsiness, changes in consciousness
• Carcinogenesis
• Alopecia, hair loss

For complete information, please consult the drug’s specific package insert or the Nursing2022 Drug Handbook® + Drug Updates.

References
 
American Cancer Society. (2019, November 22). How Chemotherapy Drugs Work: Alkylating Agents. American Cancer Society.
https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/chemotherapy/how-chemotherapy-drugs-work.
 
Colvin, M. (2003). Alkylating Agents. Holland-Frei Cancer Medicine. 6^th Edition. Hamilton. https://www.ncbi.nlm.nih.gov/books/NBK12772/
 
National Cancer Institute (n.d). Alkylating agent definition. National Institute of Health. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/alkylating-agent