Chemotherapeutic drugs

Chemotherapeutic Drugs

Chemotherapeutic drugs, commonly referred to as chemotherapy, are a class of medications used primarily to treat cancer. These drugs work by targeting and killing rapidly dividing cells, a hallmark of cancerous tissues. However, they can also affect normal cells that divide quickly, leading to a range of side effects.

Mechanism of Action

Chemotherapeutic agents can be classified based on their mechanism of action:

• Alkylating Agents: These drugs work by adding an alkyl group to the DNA molecule, which prevents the DNA from replicating and ultimately leads to cell death. Examples include cyclophosphamide and ifosfamide.

• Antimetabolites: These mimic the building blocks of DNA or RNA, interfering with their synthesis. Common antimetabolites include methotrexate and 5-fluorouracil.

• Topoisomerase Inhibitors: These drugs interfere with the enzymes topoisomerase I and II, which help unwind DNA for replication. Examples are etoposide and irinotecan.

• Mitotic Inhibitors: These prevent cell division by inhibiting mitosis. Paclitaxel and vincristine are well-known mitotic inhibitors.

• Cytotoxic Antibiotics: These are not used to treat infections but to kill cancer cells. They work by intercalating DNA strands, thus preventing replication. Doxorubicin is a prominent example.

Administration

Chemotherapy can be administered in several ways, including:

• Intravenous (IV) Injection: The most common method, where drugs are injected directly into the bloodstream.
• Oral Administration: Some chemotherapeutic agents are available in pill form.
• Intramuscular Injection: Direct injection into a muscle.
• Intrathecal Administration: Injection into the cerebrospinal fluid, used for cancers affecting the central nervous system.

Side Effects

Due to their action on rapidly dividing cells, chemotherapeutic drugs can cause a variety of side effects, including:

• Myelosuppression: Decreased production of blood cells, leading to anemia, increased risk of infection, and bleeding.
• Gastrointestinal Disturbances: Nausea, vomiting, diarrhea, and mucositis.
• Alopecia: Hair loss due to the effect on hair follicle cells.
• Fatigue: A common and often debilitating side effect.

Resistance

Cancer cells can develop resistance to chemotherapy through various mechanisms, such as:

• Drug Efflux: Increased expression of proteins that pump drugs out of the cell.
• Drug Inactivation: Enhanced ability to detoxify the drug.
• DNA Repair: Increased ability to repair DNA damage caused by the drug.

Also see

• Cancer treatment
• Radiation therapy
• Targeted therapy
• Immunotherapy

Resources

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Source: Data courtesy of the U.S. National Library of Medicine. Since the data might have changed, please query MeSH on Chemotherapeutic drugs for any updates.

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