Anticancer Drug Classification – Notes for GPAT, Pharmacist, Drug Inspector, NEETPG, NORCET and Nursing Exams

Anticancer Drug Classification – Notes

Anticancer drugs (antineoplastic agents) are used to treat malignancies by inhibiting cell growth and proliferation. They are classified based on their mechanism of action:

1. Alkylating Agents

• Mechanism: Add alkyl groups to DNA → DNA cross-linking → inhibition of replication & transcription

• Examples:

  • Cyclophosphamide

  • Busulfan

  • Melphalan

  • Nitrosoureas (e.g. Carmustine)

2. Antimetabolites

• Mechanism: Mimic natural metabolites → interfere with DNA/RNA synthesis

• Subtypes:

  • Folate analogs – Methotrexate

  • Purine analogs – 6-Mercaptopurine, Fludarabine

  • Pyrimidine analogs – 5-Fluorouracil, Cytarabine

3. Natural Products

a. Plant Alkaloids

• Vinca Alkaloids (Vincristine, Vinblastine) – inhibit microtubule polymerization

• Taxanes (Paclitaxel, Docetaxel) – stabilize microtubules

b. Topoisomerase Inhibitors

• Topoisomerase I inhibitors: Topotecan, Irinotecan

• Topoisomerase II inhibitors: Etoposide, Teniposide

c. Antitumor Antibiotics

• Bind DNA → inhibit RNA synthesis, strand breakage

• Examples: Doxorubicin, Daunorubicin, Bleomycin, Mitomycin

4. Hormonal Agents

Used in hormone-sensitive cancers (breast, prostate)

• Anti-estrogens – Tamoxifen, Fulvestrant

• Aromatase Inhibitors – Anastrozole, Letrozole

• Anti-androgens – Flutamide, Bicalutamide

• GnRH agonists/antagonists – Leuprolide, Degarelix

5. Targeted Therapy

• Target specific molecular pathways/proteins in cancer cells

• Examples:

  • Tyrosine kinase inhibitors – Imatinib, Erlotinib

  • Monoclonal antibodies – Rituximab, Trastuzumab, Bevacizumab

6. Immunotherapy

• Enhance immune system to fight cancer

• Checkpoint inhibitors: Nivolumab (PD-1), Ipilimumab (CTLA-4)

• CAR-T cell therapy

7. Miscellaneous

• Hydroxyurea

• Procarbazine

• Asparaginase

8. Supportive Agents

• Used to manage chemotherapy side effects:

  • Filgrastim (G-CSF) – neutropenia

  • Mesna – protects bladder from cyclophosphamide toxicity

  • Leucovorin – rescue for methotrexate

❓ MCQs on Anticancer Drugs

Q1. Which of the following is a purine analog?
A. Methotrexate
B. 6-Mercaptopurine
C. 5-Fluorouracil
D. Cyclophosphamide
✅ Answer: B

Q2. Paclitaxel acts by:
A. Inhibiting DNA synthesis
B. Stabilizing microtubules
C. Inhibiting thymidylate synthase
D. Alkylating DNA
✅ Answer: B

Q3. Which drug is a monoclonal antibody targeting HER2/neu?
A. Bevacizumab
B. Rituximab
C. Trastuzumab
D. Cetuximab
✅ Answer: C

Q4. Leucovorin is used as a rescue agent with:
A. Cyclophosphamide
B. Methotrexate
C. 5-Fluorouracil
D. Bleomycin
✅ Answer: B

Q5. Bleomycin’s dose-limiting toxicity is:
A. Myelosuppression
B. Nephrotoxicity
C. Pulmonary fibrosis
D. Cardiotoxicity
✅ Answer: C

Q6. Which of the following is a topoisomerase II inhibitor?
A. Irinotecan
B. Topotecan
C. Etoposide
D. Vinblastine
✅ Answer: C