Opioids/Narcotics

Question 1

What mu agonists have the best oral bioavailability?

Answer 1

Methadone and Levophanol

Question 2

What mu agonists are much more potent then morphine?

Answer 2

Hydromorphone, Oxymorphone, Levorphanol (all -orph)

Question 3

What mu agonist has a low potency?

Answer 3

Meperidine

Question 4

What is the inactive metabolite of morphine? What forms it?

Answer 4

Nomorphine

Formed by CYP3A4

Question 5

What are the active metabolites of morphine? What forms them?

Answer 5

UGT 1A1/2B7 form M-3 and M-6-glucuronide

Dehydrogenase converts morphine-> hydromorphone

Question 6

How does the half life and oral bioavailability of Methadone different from Morphine? This makes it useful for what?

Answer 6

Methadone- longer half life (27hrs vs 2 for morphine)
Better oral bioavailability (90% vs 20% for morphine)
Useful for withdrawal/maintenance and Detox

Question 7

What is the Methadone MOA?

Answer 7

Independent of Opioid receptors

Direct effect on IRK channels

Question 8

What distinguishes Meperidine from the other mu agonists?

Answer 8

Causes mydriasis instead of miosis

Has toxic metabolite normeperidine-> seizures

Question 9

What is the shortest acting High Potency Full mu Agonist, often used in childbirth?

Answer 9

Remifentanil

Question 10

What mu agonist acts on kappa, delta, and mu receptors?

Answer 10

Sufentanil

Question 11

Suffix for high potency full mu receptor agonists?

Answer 11

-entanil (anyl)

Question 12

What anti-tussive agent receives cough independently of opioid receptors?

Answer 12

Dextromethophan

Question 13

What kind of agonists are codeine, hydrocodone, and oxycodone? How does it dictate strength of response?

Answer 13

Codeine/Hydrocodone= partial agonists
Oxycodone= full agonists-> higher efficacy

Question 14

What breaks down codeine to morphine?

Answer 14

CYP2D6

Question 15

What gene duplication will an ultrafast codeine metabolizer have?

Answer 15

CYP2D6 gene duplicaiton-> more morphine then expected

Question 16

What OTC opioids are used as antidiarrheals?

Answer 16

Loperamide and Diphenoxylate

Question 17

What opioid acts as both a moderate mu agonist and inhibits catecholamine repute?

Answer 17

Tramadol

Question 18

What does a partial mu agonist do when taken with morphine? Clinical use?

Answer 18

Displaces morphine-> causes withdraw
Used for office-based detox/maintenance
Classic example-> Buprenorphine

Question 19

What is the MOA for mu receptor antagonists? What are they called?

Answer 19

Occupy/competitively inhibit other mu agonists from receptors
Antidote for opioid overdose
Naloxone IV and Naltrexone po

Question 20

What drug can be used as a peripheral acting opioid antagonist to decrease opioid-induced constipation?

Answer 20

Methylnaltrexone