III. Antimetabolites - Summary

Medical pharmacology diagram: Mechanism of action of Methotrexate (MTX) and Leucovorin Rescue. Show a detailed flowchart inside a target cancer cell. Step 1: Diet/Intestinal flora produces Folate. Step 2: Folate enters the cell via Active Transport Process. Step 3: Inside cell, Dihydrofolate Reductase (DHFR) converts Folate → Dihydrofolate (FH2) → Tetrahydrofolate (FH4). Step 4: FH4 converted to N5,N10-Methylene-FH4. Step 5: N5,N10-Methylene-FH4 used for: dUMP→dTMP (thymidylate synthase) and synthesis of Adenine, Guanine, Thymidine, Methionine, Serine. MTX shown entering cell via active transport, blocking DHFR enzyme with a large red X/inhibition symbol. Show dashed red arrows for blocked pathways. Leucovorin Rescue box on the side: "Administer N5-formyl-FH4 (leucovorin/folinic acid) → converted to N5,N10-Methylene-FH4 → bypasses the inhibited reductase". Use pink/salmon background for the cell, blue arrows for normal pathway, red dashed arrows for blocked steps, green box for leucovorin rescue. Clean medical textbook style with clear labels.

Medical education infographic: Antimetabolites Overview - Anticancer Drugs Chapter 35. Title at top: "ANTIMETABOLITES - Cell Cycle S-Phase Specific". Four colored sections side by side: 1) ANTIFOLATES (blue) - MTX inhibits DHFR, Pemetrexed inhibits DHFR + thymidylate synthase + other enzymes, Pralatrexate inhibits DHFR. Show folic acid structure. 2) PURINE ANALOGS (green) - 6-Mercaptopurine (thiol analog of hypoxanthine), Fludarabine (purine nucleotide analog prodrug), show purine ring. 3) PYRIMIDINE ANALOGS (orange) - 5-Fluorouracil (fluorine at position 5 of uracil), Cytarabine, Gemcitabine, Capecitabine. Show pyrimidine ring with F atom highlighted. 4) OTHER (purple) - Azacitidine, Cladribine. Bottom row: Key concept box "All antimetabolites structurally resemble normal purines/pyrimidines and interfere with DNA/RNA synthesis". Clean colorful medical infographic style with icons, arrows, molecular structure sketches.

Medical pharmacology visual summary table: "Antimetabolites - Key Drug Profiles" for exam study. Organized as a visual grid with 8 drug cards. Each card has drug name in bold header, mechanism arrow diagram, therapeutic uses, and adverse effects. Cards: 1) METHOTREXATE - inhibits DHFR - leukemia/lymphoma/psoriasis/RA - myelosuppression/renal/mucositis. 2) 6-MP - inhibits purine synthesis - ALL maintenance - myelosuppression/hepatotoxicity, reduce dose 50-75% with allopurinol. 3) FLUDARABINE - incorporated into DNA/RNA - CLL/hairy cell leukemia/NHL - immunosuppression/myelosuppression. 4) 5-FU - blocks dUMP→dTMP - colorectal/breast/GI cancers - hand-foot syndrome/mucositis. 5) CAPECITABINE - oral 5-FU prodrug - breast/colon - hand-foot syndrome. 6) CYTARABINE - inhibits DNA polymerase - AML/CNS - conjunctivitis with high dose. 7) GEMCITABINE - blocks DNA synthesis, radiosensitizer - lung/pancreas - flu-like syndrome. 8) AZACITIDINE - myelosuppression - MDS/leukemia. Color coded by drug class. Clean medical education poster style.

Medical pharmacology diagram: Mechanism of action of Methotrexate (MTX) and Leucovorin Rescue. Show a detailed flowchart inside a target cancer cell. Step 1: Diet/Intestinal flora produces Folate. Step 2: Folate enters the cell via Active Transport Process. Step 3: Inside cell, Dihydrofolate Reductase (DHFR) converts Folate to Dihydrofolate (FH2) to Tetrahydrofolate (FH4). Step 4: FH4 converted to N5,N10-Methylene-FH4. Step 5: Used for dUMP to dTMP and synthesis of Adenine, Guanine, Thymidine, Methionine, Serine. MTX blocks DHFR with a large red X. Leucovorin Rescue box: bypasses blocked enzyme. Pink cell background, blue arrows for normal pathway, red dashed arrows for blocked steps, green box for leucovorin rescue. Clean medical textbook style.

Medical education infographic: Antimetabolites Overview for pharmacology students. Title: "ANTIMETABOLITES - S-Phase Specific Anticancer Drugs". Four color-coded sections: 1) ANTIFOLATES in blue - MTX inhibits DHFR, Pemetrexed inhibits DHFR plus thymidylate synthase, Pralatrexate inhibits DHFR. 2) PURINE ANALOGS in green - 6-Mercaptopurine thiol analog of hypoxanthine, Fludarabine purine nucleotide analog prodrug for CLL. 3) PYRIMIDINE ANALOGS in orange - 5-Fluorouracil fluorine at position 5 blocks dUMP to dTMP, Cytarabine, Gemcitabine radiosensitizer, Capecitabine oral prodrug. 4) OTHER in purple - Azacitidine for MDS, Cladribine for leukemia. Bottom concept box: All antimetabolites resemble normal purines/pyrimidines and disrupt DNA/RNA synthesis. Colorful medical poster style with icons and arrows.

Medical pharmacology study card grid: "Antimetabolites Drug Profiles" - 8 drug summary cards arranged in a 2x4 grid. Each card has colored header with drug name, a small mechanism arrow, uses, and adverse effects listed. Card 1 METHOTREXATE yellow: inhibits DHFR, uses leukemia lymphoma psoriasis RA Crohn, adverse myelosuppression renal mucositis, leucovorin rescues. Card 2 6-MERCAPTOPURINE green: purine analog inhibits synthesis, uses ALL maintenance Crohn, adverse myelosuppression hepatotoxicity jaundice, reduce dose 75 percent with allopurinol. Card 3 FLUDARABINE blue: incorporated into DNA RNA, uses CLL hairy cell leukemia NHL, adverse immunosuppression myelosuppression, IV only. Card 4 5-FLUOROURACIL orange: blocks thymidylate synthase dUMP to dTMP, uses colorectal breast gastric ovarian pancreatic, adverse hand-foot syndrome mucositis coronary vasospasm. Card 5 CAPECITABINE pink: oral 5-FU prodrug, uses breast colon cancer, hand-foot syndrome, take with meal. Card 6 CYTARABINE purple: inhibits DNA polymerase, uses AML CNS lymphoma, conjunctivitis high dose give steroid eye drops. Card 7 GEMCITABINE teal: blocks DNA synthesis potent radiosensitizer, uses lung pancreatic, flu-like syndrome thrombocytopenia. Card 8 AZACITIDINE red: myelosuppression, uses MDS leukemia, stability IV only 60 minutes. Clean colorful medical exam study poster.

Medical pharmacology diagram: 6-Mercaptopurine and Fludarabine mechanism of action. Two side-by-side panels. Left panel: 6-MERCAPTOPURINE (6-MP) - show hypoxanthine structure alongside 6-MP structure with SH group highlighted, arrow showing 6-MP blocks purine synthesis pathway, blocks conversion steps in de novo purine synthesis, incorporated into DNA causing strand breaks. Note: Azathioprine converts to 6-MP in body. Allopurinol increases 6-MP toxicity so reduce dose by 50-75 percent. Right panel: FLUDARABINE - show it as prodrug, phosphate removed in plasma to form 2-F-araA, enters cells, phosphorylated by deoxycytidine kinase, triphosphate incorporated into DNA and RNA blocking S phase synthesis. Resistance mechanisms shown. Both panels with color-coded arrows, inhibition symbols as red X marks, DNA double helix shown as target. Clean medical textbook illustration style with blue and green color scheme.

Medical pharmacology mechanism diagram: 5-Fluorouracil (5-FU) mechanism of action. Show the pyrimidine ring of uracil with hydrogen atom at position 5 replaced by fluorine atom labeled clearly. Main pathway: 5-FU converted to FdUMP (fluorodeoxyuridine monophosphate) which forms stable ternary complex with thymidylate synthase enzyme and N5,N10-methylene-FH4 cofactor. This blocks conversion of dUMP to dTMP (deoxythymidine monophosphate). Result: NO thymidine available for DNA synthesis causing cell death. Secondary pathway: 5-FU also incorporated into RNA as FUTP disrupting RNA function. Show S phase cell cycle icon. Therapeutic uses listed: colorectal, breast, ovarian, pancreatic, gastric cancers, and topical use for basal cell carcinoma. Adverse effects: hand-foot syndrome (palmar-plantar erythrodysesthesia), mucositis, myelosuppression, coronary vasospasm. Orange and red color scheme, clean medical diagram style with molecular structures.