Antimetabolites: Nursing pharmacology

Antimetabolites are medications used primarily for cancer treatment. They are most effective against hematologic malignancies, like leukemia, lymphoma, and myelodysplastic syndrome; but they can also be effective against solid tumors, like breast cancer, head and neck cancer, and osteosarcoma.

Based on the specific substance with which they interfere, antimetabolites can be classified into folic acid analogs, like methotrexate, which can be administered orally, subcutaneously, intramuscularly, intravenously, or intrathecally; pyrimidine analogs, like fluorouracil, which can be administered topically or intravenously, and cytarabine, which can be administered subcutaneously, intravenously, or intrathecally; purine analogs, like mercaptopurine, taken orally, as well as cladribine and fludarabine, administered intravenously; and ribonucleotide reductase inhibitors, such as hydroxyurea, which can be administered orally or intravenously.

Okay, the reason antimetabolites are effective for cancer treatment is that they disrupt DNA synthesis.

They do that either by mimicking folic acid, or nucleobases, such as pyrimidines and purines; or by inhibiting enzymes that are involved in the pathway, such as adenosine deaminase and ribonucleotide reductase.

As a result, they stop DNA replication and cell proliferation, eventually leading to cancer cell death. Unfortunately, this action can also increase the risk of serious side effects.