Opioid Pharmacology

Question 1

What type of opioid agonist is morphine
codeine
hydrocodone
meperidine?

Answer 1

Pure opioid agonist at the mu and Kappa receptor

Question 2

What is pentazocine MOA?

Answer 2

antagonist at mu

agonist at kappa

Question 3

What is butorphanol MOA?

Answer 3

partial agonist at mu

agonist at kappa

Question 4

What is buprenorphine MOA?

Answer 4

partial agonist at mu

antagonist at kappa

Question 5

What is mechanism of naloxone and naltrexone?

Answer 5

Antagonist at mu

antagonist at kappa

Question 6

Are oral or parenteral doses of morphine larger?

Answer 6

morphine undergoes significant first-pass metabolism (conjugation), so oral doses are larger than parenteral doses

Question 7

What is the triad of opioid overdose?

Answer 7

• coma
• respiratory depression
• pinpoint pupils

Question 8

How is fentanyl metabolized?

Answer 8

100X more potent, same adverse effects… CYP3A4 substrate, t1/2 2-4 hrs

Question 9

What is notable about fentanyl?

Answer 9

notable for multiple formulations including 
IM
 IV
transdermal
transmucosal
 nasal spray
 lozenge on stick
 buccal tablets

Question 10

What drugs are used for induction of anesthesia, maintenance of anesthesia in combination with other agents, and as sole anesthetic agents?

Answer 10

1. Alfentanil
2. Remifentanil
3. Sufentanil

Question 11

What drug is an IV opioid with rapid onset and brief duration due to rapid metabolism by blood esterases… effects begin in minutes and end 5-10 min after infusion is stopped, also used for immediate postoperative analgesia?

Answer 11

Remifentanil

Question 12

What drug is often abused by healthcare workers because it has anticholinergic effects, so lacks pinpoint pupils of other opioids, also contributing to eradication efforts

Answer 12

Meperidine (demerol)

Question 13

What is methadone MOA?

Answer 13

Shares properties with morphine, is an NMDA receptor antagonist with a long duration of action

Question 14

What has a higher lipid solubility than morphine and gives a greater high?

Answer 14

Heroin

Question 15

What is indicated for sever/moderate pain, is reversed by naloxone, and is more water soluble so can be diluted in a smaller volume for injections?

Answer 15

Hydromorphone (dilaudid)

-oxymorphone, levorphanol

Question 16

~10% of codeine is metabolized to morphine by what enzyme? What happens if this enzyme is absent?

Answer 16

10% of each dose of codeine is metabolized to morphine by CYP2D6 … required for analgesia
• some lack this gene so codeine is ineffective

Question 17

What opioid agonist is extremely effective as a cough suppressant?

Answer 17

Codeine

Question 18

What enzyme metabolizes oxycodone? Why is this significant?

Answer 18

CYP3A4 metabolizes oxycodone–> inducers (e.g., carbamazepine, phenytoin) can lower levels and inhibitors (e.g., “azole” antifungal drugs) can raise levels

Question 19

What is pentazocine MOA?

Answer 19

• agonist-antagonist opioid prototype

- Agonist of kappa opiate receptors and antagonist of mu opiate receptors in the CNS–> inhibits ascending pathway

Question 20

What is MOA of oxycodone

Answer 20

moderate to strong opioid agonist, similar to codeine

Question 21

What is MOA of hydrocodone?

Answer 21

moderate to strong opioid agonist, similar to codeine

• available only in combination with other drugs (acetaminophen, aspirin, ibuprofen

Question 22

What is MOA of butorphanol?

Answer 22

• agonist-antagonist opioid usted to treat mild to moderate pain
• kappa opioid receptor agonist
• mu opioid receptor partial agonist

Question 23

What drug differs significantly from other agonist-antagonists in that it is a kappa opioid receptor antagonist and partial agonist at mu opioid receptors?

Answer 23

Buprenorphine - used primarily to treat addicts

• prolongs QT interval, so risk of fatal dysrhythmias

• can cause spasm of sphincter of Oddi, poses risk for patients with pancreatitis or biliary disease

Question 24

What type of drug is naloxone? what is it used for?

Answer 24

Narcan in a pure opioid antagonist used for reversal of effects of most opioid agonists