Multicyclic Opioids 3

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Multicyclic Opioids 3
2014-04-05 21:52:27
Multicyclic Opioids
Multicyclic Opioids 3
Multicyclic Opioids 3
Show Answers:

  1. What receptor do these drugs work at and what structure indicates this?
    • Pentacyclic
    • “Antagonism”
    • Mu antagonists:
    • N-allyl or N-cyclopropylmethyl on the nitrogen atom
    • 7,8 dihydro-6-one
    • 14  B-OH
    • (Naloxone and Naltrexone)

  2. By what mechanism do these drugs cause high affinity mu antagonism?
    • Induce conformational changes that uncouples the receptors from their G-proteins
    • (Naloxone and Naltrexone)

  3. If you had a patient on a mu agonist,what considerations would need to be made prior to staring one of these drugs?
    • To prevent withdrawal:
    • Must be agonist free for 7-10 days before one of these antagonists can be administered
    • Unless trying to rescue a patient from fatal overdose (Ggive STAT)
    • (Naloxone and Naltrexone)

  4.  How does the potency of these two drugs compare?
    • Naltrexone is twice as potent as naloxone
    • Due to an enhanced lipophilicity of Naltrexone and distribution to CNS

  5. Is this drug orally active?

  6. Why is this drug useful for opioid addiction therapy?
    • Mu antagonist
    • Blocks opioid receptors in opioid-free patients = thwarts euphoria of agonists if patient relapses

  7. (True/False) Naltrexone has shown efficacy in the treatment of alcoholism.

  8. Low doses (4.5 mg daily) naltrexone has shown efficacy in what ailment?
    Bowel ulcerations and enhancing immunity in active Crohn’s disease

  9. Why would you choose an IM version over an oral version of Naltrexone for opioid addiction therapy?
    • IM contains a slow release polymer that makes it last for 4 weeks
    • Increases convenience and adherence
  10. How would the daily exposure to Naltrexone compare between an IM Q4weeks and a 50 mg tablet QD and why?
    • Greater exposure with the IM version
    • Avoids 1st pass metabolism so: Much less metabolite is formed IM

  11. What is the primary metabolite of this drug and what enzyme produces it?
    • 6B-naltrexo
    • Cytosolic enzyme dihydrodiol dehydrogenase
    • (Naltrexone)

  12.  is this drug orally active?
    • No
    • (Naloxone)

  13. Why is this drug not orally active?
    • Due to inactivating pre-hepatic and first pass metabolism
    • Allyl group is oxidized and conjugated
    • (Naloxone)

  14. What is the primary urinary metabolite of this drug?
    • C3 glucuronide
    • (Naloxone)

  15. In what form is this drug available?
    • IV
    • (Naloxone)

  16. What is this drug used for?
    • Reverse life-threatening opioid overdose, respiratory and CNS depression
    • (Naloxone)

  17. Will this drug precipitate withdrawal in mu agonist users?
    • Yes, mu Antagonist
    • (Naloxone)

  18. Why will symptom of withdrawal be short lived when this drug is given to a mu agonist user?
    • 1-2 hour half-life
    • (Naloxone)

  19. What was this drug used for?
    • IV use in reversing life-threatening opioid overdose
    • Mu antagonist
    • (nalmefene)

  20. Why was this drug likely taken off the market?
    • Excessively long DOA (11 hours) to be used for reversing opioid overdose
    • Caused prolonged withdrawal symptoms
    • (nalmefene)

  21.  Is this drug orally active?
    • Yes
    • (nalmefene)

  22. Why does this drug have such a long half life (11 hours)?
    • High affinity binding as a mu antagonist due to the 6-exocyclic methylene moiety
    • (nalmefene)

  23. Other than treating life threatening overdose, what other uses could this drug have due to its long half life and high oral bioavailability?
    • Preventing relapse in recovering alcoholics
    • Blocking mu agonist effects of fentanyl