Opioids

Question 1

Opioid tolerance mechanism

Answer 1

phosphorylation and uncoupling
displacement of G proteins by arrestins
unable to get the same decrease in cAMP - higher dose required

Question 2

Opioid MoA

Answer 2

decrease cAMP, decrease K, hyperpolarization, decrease substance P
release dopamine and GABA

Question 3

Morphine MoA + excretion

Answer 3

U receptor strong agonist
renal excretion
Poor CNS (BBB)

Question 4

Opioid common ADR

Answer 4

Constipation
Nausea and vomiting
Respiratory depression

Question 5

Fentanyl MoA + metabolism

Answer 5

Strong agonist, x100 of morphine
High affinity u receptors
crosses BBB
CYP34A

Question 6

Codeine MoA

Answer 6

Moderate agonist (1/10 of codeine)

Question 7

Codeine uses

Answer 7

Cough depressant

mild-moderate analgesia

Question 8

Buprenorphine MoA

Answer 8

U receptor partial agonist- high affinity for receptor, not easily displaced
K receptor antagonist

Question 9

Buprenorphine metabolism

Answer 9

CYP34A

Biliary excretion

Question 10

Buprenorphine uses

Answer 10

Opioid addiction due to mixed effects

Question 11

Naloxone MoA

Answer 11

Competitive U antagonist
Doesn’t displace buprenoprhine
Short T1/2 - give slow infusion so patient doesnt withdraw
use for opioid OD