NEURO - Opioids

Question 1

List of opioid analgesics

Answer 1

Morphine
Fentanyl
codeine
Loperamide
diphenoxylate
methadone
meperidine
dextromethorphan
pentazocin
nalbuphine
Buprenorphine

Question 2

Mechanism of tolerance of opioids

Answer 2

NMDA phosphorylation of opioid receptors via glutmate

*decrease this tolerance with glutamate antagonism i.e. ketamine

Question 3

mu ligand

Answer 3

beta-endorphin (form POM-C)

Question 4

kappa ligand

Answer 4

dyorphin

Question 5

delta ligand

Answer 5

enkephalin

Question 6

MOA of opioid analgesits

Answer 6

open K+ channels
Close Ca++ channels

.: Decreases synaptic transmission

Inhibits release of ACh, NE, 5-HT, glutamate, substance P

Question 7

Opioid for cough

Answer 7

dextromethorphan

Question 8

opioids for diarrhea

Answer 8

loperamide
diphenoxylate
(don’t cross BBB)

Question 9

opioids for heroin addicts

Answer 9

methadone 
Suboxone 
Naloxone 
Naltrexone 
Methylnaltrexone

Question 10

opioid analgesic that causes inhibition of muscarinic receptors

Answer 10

meperidine

.: classic s/s of opioid intoxication are REVERSED! i.e. dilated pupils

Question 11

Opioid analgesics that can cause serotonin syndrome

Answer 11

meperidine (via normeperidine metabolite)

Dextromethorphan

Question 12

Mixed agonist-antagonists

Answer 12

Nalbuphine
Pentazocin

kappa agonist
mu antagonist

Question 13

Methadone

Answer 13

methadone (long-acting agonist)

Question 14

Suboxone

Answer 14

(buprenorphine = partial agonist, SL; + naloxone = antagonist, IV)

Question 15

Naloxone

Answer 15

(antagonist; acute OD)

Question 16

Naltrexone

Answer 16

(antagonist; long t1/2, decrease alcohol and heroin cravings)

Question 17

Mehtynaltrexone

Answer 17

Treats opioid-induced constipation: antagonist that can’t cross BBB, so doesn’t induce withdrawal

Question 18

General use of opioids

Answer 18

Pain, acute pulmonary oedema

Question 19

Tolerance does NOT develop to:

Answer 19

miosis and constipation

Question 20

Opioids and head trauma

Answer 20

contraindicated; cause vasodilation and histamine release

Question 21

Opioids and smooth muscle effects

Answer 21

Longitudinal relaxation, 
but circular constriction:
- cramps, constipation, decreased peristalsis
- urinary retention
- sphincter of oddi constriction
- miosis

Question 22

Butorphanol

Answer 22

kappa agonist and mu partial agonist

Question 23

agonist-partial agonist

Answer 23

Butorphanol - kappa agonist and mu partial agonist

Question 24

Butorphanol use

Answer 24

severe pain i.e. labour, migraine

Causes less respiratory depression

Question 25

Butorphanol AE

Answer 25

withdrawal if they are on a full agonist

Not easily reversible with naloxone

Question 26

Tramadol MOA

Answer 26

weak opioid agonist

5HT and NE repute inhibitor

Question 27

Tramadol use

Answer 27

chronic pain

Question 28

Tramadol AE

Answer 28

Opioid stuff
Lowers seizure threshold
Serotonin syndrome