Table 1.

Chemotherapeutic agents: classification and mechanisms of action.

	Mechanism of Action	Site of Action	Examples
Antimetabolites	Interfere with DNA/RNA synthesis by inhibiting purine ring synthesis, ribonucleotide reductase or DNA monomers synthesis normally causing cell death during the S phase of cell growth.	Purines and pyrimidines synthesis	Thioguanine Mercaptopurine Methotrexenate
		Ribonucleotides	Hydroxycarbamide
		DNA monomers	Methotrexate 5-Fluorouracil
		DNA synthesis	Cytarabine Bleomycin
Intercalating agents	Interfere with DNA/RNA synthesis, preventing cell duplication		Topoisomerase inhibitors (Etoposide Topotecan, Irinotecan) Antibiotics (anthracyclines, Chromomycin, Doxorubicin)
Cross-linking agents	Cross-link two DNA bases together preventing DNA from being separated during DNA synthesis or transcription. Nucleotide mispairing, leading to mutations.		Alkylating agents Nitrosoureas Platinum-based coordination complexes
Enzyme	Protein synthesis inhibition, leading to cell death by apoptosis	Protein synthesis	L-Asparaginase
Microtubule damaging agents	Anti-mitotic agents that inhibit cell proliferation by disrupting the normal function of the mitotic spindle.	Microtubules	Taxanes Vinca alkaloids Taxol Colchicine
Enzyme inhibitors	Interfere with normal cell metabolism, leading to cell death	Enzyme activity	Methotrexate Kinase inhibitors
Angiogenesis inhibitors	Inhibit endothelial cells’ proliferation and tumor growth	Angiogenesis	Endostatin