Pharmacology Exam 2

  1. Efflux transporters
    • pump things out of the cells into the intestinal lumen
    • P-gp
    • BCRP
    • MRP2
    • OCT1? Cations
  2. P-glycoprotein (P-gp)
    • efflux pump for anticancer drugs
    • member of ATP binding cassette (ABC transporters)
  3. P-gp location
    • intestine
    • liver
    • kidney
    • BBB
  4. P-gp substrates
    • HIV Protease
    • Digoxin
    • Rifampin
    • Anticancer
    • Anticonvulsants
  5. use of P-gp inhibitors
    use inhibitor along with desired substrate to increase effect
  6. p-gp inducers
    • phenobarbital
    • clotrimazole
    • bad with desired substrates!
  7. Phase I reactions
    CYP increases hydrophilicity
  8. Phase II
    • conjugation reactions
    • use of transferases to increase water solubility
  9. CYP3A4/5/7
    40% of drug metabolism
  10. CYP Family
    • >40% identical genetic info
    • CYP1, CYP2...
  11. CYP Subfamily
    • 40-55% identical
    • CYP2A, CYP2B
  12. Withing CYP subfamilies
    • >55% identical
    • CYP2b1, CYP2b2
  13. CYP Characterstics
    • Heme protein
    • Supporting enzymes CYP reductase and cytochrom b5
    • 450nm in the reduced (Fe2+) form
    • 6000 proteins
  14. CYP System
    • requires cytochrome B5 and CYP reductase
    • important for e- transfer
    • outputs a more polar metabolite
  15. CYP catalyzed reactions
    • C-H bond hydroxylation
    • Epoxidation (causes oxidative stress)
    • S-Oxidation
    • N-Hydroxylation
    • O-Dealkylation
    • N-Dealkylation
  16. Unique characteristics of CYP
    • substrate diversity
    • enzyme diversity
    • substrate specificity
    • regio and stereoselectivity
    • atypical kinetics
    • enzyme cooperativeity
  17. Substrate diversity of CYP
    adjusts size of active site to fit multiple drugs
  18. Atypical kinetics
    one drug binding may facilitate binding of another drug (sigmoidal)
  19. Enzyme cooperativity
    • Increase kCat+Decrease S50=
    • Increased efficacy of drug
  20. CYP3A substrates
    • calcium channel blockers
    • HIV protease inhibitors
    • non sedating antihistamines
  21. CYP3A Inhibitors
    • ketoconazole
    • erythromycin
    • grapefruit juice
  22. CYP3A Inducers
    • rifampin
    • ritonavir
    • boosters for anti-retroviral therapies
  23. Why is CYP 3A4 involved in majority of drug interactions?
    responsible for metabolizing numerous drugs
Author
Rx2013
ID
39019
Card Set
Pharmacology Exam 2
Description
Enzymes of DI/ADR
Updated