Chemotherapy involves the use of cytotoxic drugs that target rapidly dividing cancer cells by interfering with DNA replication, cell division, or other vital cellular processes. These agents are systemic and can affect both malignant and normal rapidly dividing cells.
Key Points:
- Classes: Includes alkylating agents, antimetabolites, anthracyclines, taxanes, vinca alkaloids, topoisomerase inhibitors, and others.
- Mechanism: Varies by class but generally disrupts DNA synthesis/repair or mitosis to induce cancer cell death.
- Use: Curative, adjuvant, neoadjuvant, palliative, or in combination regimens to improve efficacy and reduce resistance.
- Adverse Effects: Myelosuppression, nausea/vomiting, mucositis, alopecia, neuropathy, organ-specific toxicities (e.g., cardiotoxicity with anthracyclines).
- Pharmacist Role:
- Verify appropriate dosing and regimen.
- Monitor and manage adverse effects.
- Educate patients on administration, side effects, and supportive care.
- Check for drug interactions and renal/hepatic dose adjustments.
- Support adherence and coordinate multidisciplinary care.
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| Chemotherapy Class | Examples | Mechanism of Action | Key Indications | Key Toxicities | Monitoring & Pharmacist Role |
|---|---|---|---|---|---|
| Alkylating Agents | Cyclophosphamide, Ifosfamide, Melphalan | Cross-link DNA strands → inhibit replication | Breast cancer, lymphoma, multiple myeloma, ovarian cancer, sarcomas | Myelosuppression, hemorrhagic cystitis (ifosfamide), infertility, secondary malignancies | CBC, hydration, mesna for ifosfamide, counsel on fertility |
| Antimetabolites | Methotrexate, 5-Fluorouracil, Cytarabine, Capecitabine | Mimic nucleotides → inhibit DNA/RNA synthesis | Leukemias, breast cancer, colorectal cancer, head and neck cancers | Myelosuppression, mucositis, diarrhea, hepatotoxicity | CBC, liver function tests, leucovorin rescue (methotrexate), hydration |
| Anthracyclines | Doxorubicin, Epirubicin | Intercalate DNA, inhibit topoisomerase II, generate free radicals | Breast cancer, lymphoma, sarcomas, leukemias | Cardiotoxicity, myelosuppression, mucositis, alopecia | Baseline and periodic LVEF, CBC, counsel on cardiac symptoms |
| Taxanes | Paclitaxel, Docetaxel | Stabilize microtubules → inhibit mitosis | Breast cancer, lung cancer, ovarian cancer, prostate cancer | Peripheral neuropathy, myelosuppression, hypersensitivity reactions | CBC, premedicate for hypersensitivity, neuropathy assessment |
| Vinca Alkaloids | Vincristine, Vinblastine | Inhibit microtubule formation → block mitosis | Leukemias, lymphomas, solid tumors | Neurotoxicity (peripheral neuropathy, constipation), myelosuppression | Monitor neurotoxicity, bowel function, dose adjustments |
| Topoisomerase Inhibitors | Irinotecan, Topotecan | Inhibit topoisomerase I → DNA damage | Colorectal cancer, lung cancer, ovarian cancer | Diarrhea (irinotecan), myelosuppression | CBC, diarrhea management, hydration |
| Platinum Agents | Cisplatin, Carboplatin, Oxaliplatin | Cross-link DNA → inhibit replication | Lung cancer, ovarian cancer, bladder cancer, testicular cancer, colorectal cancer | Nephrotoxicity (cisplatin), neuropathy, myelosuppression | Renal function, hydration, electrolytes, neuropathy monitoring |
| Others | Bleomycin, L-Asparaginase | Varied (free radicals, enzyme depletion) | Hodgkin lymphoma, testicular cancer, ALL | Pulmonary toxicity (bleomycin), hypersensitivity (L-asparaginase) | Pulmonary function, hypersensitivity monitoring |