Opioids

Question 1

4 opioid receptors

Answer 1

Mu
Kappa
Delta
Gamma

Question 2

Opioid MOA

Answer 2

all are G-protein coupled receptors -> hyperpolarization -> inhibition of adenylyl cyclase -> decreased cAMP
-> decreased Ca channel opening

*inhibits pre and postsynaptic responses to ACh and substance P

Question 3

Receptors and their purpose

Answer 3

Mu 1 - supraspinal analgesia
Mu 2 - respiratory depression and dependence
Kappa - sedation and analgesia
Gamma - analgesia and epileptogenic

Question 4

Fentanyl

Answer 4

very lipid soluble and lowest molecular weight

- very readily absorbed

Question 5

Morphine

Answer 5

relatively low solubility and slow onset of action

• slow passage thru BBB = prolonged duration
• M6G metabolite = ACTIVE

Question 6

Sufentanil

Answer 6

Fast acting, quick off as well

Question 7

Alfentanil

Answer 7

most rapid onset (nonionized fraction)

Question 8

Redistribution of opioids

Answer 8

can be retained in the lungs

• uptake decreased: prior drugs or inhalation
• uptake increased: tobacco use

Question 9

Biotransformation

Answer 9

All opioids depend on CytoP450 except Remifentanil

- high hepatic extraction ratio = dependent on blood flow

Question 10

Remifentanil

Answer 10

metabolized by plasma esterases, immediately comes off when infusion is stopped

Question 11

Codeine and Meperidine

Answer 11

must be metabolized to become active

Question 12

Opioid effects on organ systems

Answer 12

CV: large doses can sympathectomy => vagal bradycardia
Resp: dose dependent resp depression (blunts hypercapnic resp drive)
CNS: decrease CMRO2, CBF, ICP
- N/V
GI: slows gut motility (cannot develop tolerance to)