Opioid Analgesics

Question 1

δ receptor location and function

Answer 1

Brain - analgesia/antidepressant/physical dependence

Question 2

κ receptor location and function

Answer 2

Brain/Spinal Cord - sedation/spinal analgesia/miosis

Question 3

µ receptor location and function

Answer 3

Brain/Spinal Cord - supraspinal analgesia/physical dependence/respiratory depression/euphoria/

Question 4

What is the role of the brain stem in pain?

Answer 4

It plays a role in the anticipation and perception of pain

Question 5

What does tissue damage release to relay the pain message?

Answer 5

It releases histamine and bradykinin which lead to the release of prostaglandins and substance P

Question 6

Where is pain elaborated on the spinal cord?

Answer 6

Pain goes to the dorsal horn of the spinal cord and up the STT to the reticular formation and limbic systems

Question 7

How do opioids induce analgesia?

Answer 7

They reduce the amount of information reaching the brain which induces the analgesic effect

Question 8

How do opiods act on pre-synaptic neurons?

Answer 8

They act by blocking Ca2+ which leads to the decreased release of NT

Question 9

How do opiods act on post-synaptic neurons?

Answer 9

They stimulate K+ channels which will hyper polarize and result in decreased action potentials

Question 10

Morphine target and function

Answer 10

µ receptor

Use for extreme pain found in MI or chronic cancer for example

Question 11

Morphine toxicity

Answer 11

Constipation
Addiction
Tolerance

Question 12

Morphine antidote

Answer 12

Naloxine

Question 13

Meperidine target and function

Answer 13

κ receptor

Used for severe pain like that in biliary spasm

Question 14

Meperidine toxicity

Answer 14

Side effects caused by its metabolite norpethidine

Respiratory Depression

Question 15

Is naloxone an antidote for meperidine?

Answer 15

NO. Meperidine has anticholinergic activity whichi likely makes naloxone ineffective

Question 16

Hydrocodone target and function

Answer 16

µ and δ

Used for moderate pain in coughing and it works similarly to morphine

Question 17

Hydrocodone toxicity

Answer 17

Constipation
Respiratory Depression
Nausea

Question 18

What receptor is euphoria mediated via?

Answer 18

µ. It inhibits the inhibition of DOPA which leads to increased DOPA

Question 19

Pentazocine target and function

Answer 19

δ agonist
κ agonist
µ antagonist

Used as a mild to moderate analgesic for dental extraction

Question 20

Pentazocine toxicity

Answer 20

Hallucination

CV effects

Question 21

What is the antagonistic effect of pentazocine?

Answer 21

Antagonizes the analgesic effects of morphine and meperidine

Question 22

Naloxone target and function

Answer 22

δ antagonist
κ antagonist
µ antagonist

Prevents and reverses the effects of opioids like respiratory depression/sedation/hypotension

Question 23

Naloxone toxicity

Answer 23

Change in mood
Trembling
Change in heart rhythm

Question 24

Methadone target and function

Answer 24

δ agonist
µ agonist

Strong opioid analgesic used to treat coughing and dependence on opioid drugs

Question 25

Methadone toxicity

Answer 25

Dependence