Pharmacology 2 Sulfonamides, Quinolones, chemo

  1. Sulfadiazine
    • Orally absorbed
    • Protein bound
    • CYP2C9
    • Concentration in urine higher than plasma
    • weak acid, more soluble in alkaline urine
  2. Mafenide (Sulfamylon)
    • insoluble
    • topical
    • prevents wound infection
  3. sulfasalazine (Azulfidine)
    • insoluble
    • prodrug
    • poor oral absorption
    • hydrolyzed to active form (5ASA and sulfapyridine)
    • used for intestinal infections
  4. Sulfisoxazole (Sulfafurazol)
    • more soluble than sulfadiazine in urine
    • achieves high concentration in urine
    • excreted unchanged
    • used for UTI
  5. Trimethoprim (Proloprim, Trimpex)
    • Inhibitor of DHFR
    • highly selective for bacterial DHFR (>5000-fold)
    • used for UTI
  6. Trimethoprim/sulfamethoxazole (trimplex/gantanol)
    • combo blocks folate metabolism
    • synergistic effect: MIC of combo is 1/4 of MIC for either drug alone
  7. What is the role of folic acid?
    supports synthesis of thymidine by dividing cells
  8. What inhibits folic acid synthesis?
  9. Bacteria synthesize folic acid from what?
    P-aminobenzoic acid (PABA)
  10. How to vertebrates get folic acid?
    ingest it
  11. Sulfonamides block which step of folic acid synthesis?
    Pteridine + PABA --> dihydropteroic acid

    enzyme: dihydropteroate synthase
  12. Trimethoprim blocks which step of the folic acid synthesis?
    Dihydrofolic acid --> tetrahydrofolic acid

    enzyme: dihydrofolate reductase
  13. Methotrexate (rheumatrex, trexall)
    • Tight binding inhibitor of DHFR from all sources
    • no selectivity for microorganisms
    • selective toxicity for cancer cells; high demand for nucleic acid
    • resistance due to elevated levels of DHFR in resistant cells
    • Used in rheumatoid arthritis and psoriasis
  14. What medications target cell wall syntheis?
    penicillin, cephelosporins, bacitracin, vancomycin
  15. What medications target protein syntheis?
    chloramephenicol, erythromycin, tetracycline, streptomycin
  16. what medication target plasma membrane?
    Polymyxin B
  17. What medications inhibit synthesis of essential metabolites?
    sulfanilamides, trimethoprim
  18. Nalidixic acid (nevigramon, Neggram)
    • Early quinolone antibiotic
    • relatively weak activity and susceptible to bacterial resistance
    • Used for lower UTI
  19. Fluoroquinolones
    • Ciprofloxacin (cipro, proquin)
    • ofloxacin (floxin)
    • Much more effective than nalidixic acid
  20. Cyclophosphamide (cytoxan, Neosar)
    • For lymphoma, breast cancer, ovarian cancer
    • IV or oral
    • decrease in blood cell counts
    • N/V, ab pain
    • decreased appetite
    • hair loss
    • bladder damage
    • fertility impairment
    • lung or heart damage (with high doses)
    • secondary malignancies (rare)
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Pharmacology 2 Sulfonamides, Quinolones, chemo
Pharmacology 2, Sulfonamides, Quinolones, chemo