Opioid Analgesics

Question 1

Morphine,
Hydromorphone &
Oxymorphone

Answer 1

Receptor:

• U, high
• d & K, low

Use:
- severe pain

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 2

Merperidine

Answer 2

Receptor:
- U agonist

Use:
- acute pain, short-term

Adverse:

• tremors
• muscle twitches
• seizures
• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 3

Fentanyl

Answer 3

Receptor:
- U agonist

Use:
- severe pain

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 4

Methadone

Answer 4

SNRI

Receptor:

• U agonist
• NMDA antagonist

Use:

• severe pain
• opioid withdrawl, addicted
• detoxification & maintenance

Adverse:

• QT prolongation
• Torsades de pointes
• death
• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 5

Levorphanol

Answer 5

SNRI

Receptor:

• U, d & K agonist
• NMDA antagonist

Use:
- severe pain

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 6

Oxycodone

Answer 6

Receptor:

Use:
- moderate to severe pain

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 7

Hydrocodone

Answer 7

• w/acetaminophen or NSAID

Receptor:

Use:
- moderate to severe pain

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 8

Codeine

Answer 8

• conv. to morphine via CYP2D6

Receptor:

Use:

• mild to moderate pain
• cough

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 9

Pentazocine,
Butorphanol &
Nalbuphine

Answer 9

Receptor:

• K agonist
• U antagonist

Use:
- opioid addiction

Adverse:

• psychomimetic effects
• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 10

Buprenorphine

Answer 10

Receptor:

• weak U agonist
• K antagonist

Use:
- opioid addiction

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 11

Tramadol

Answer 11

• SNRI

Receptor:
- weak U agonist

Use:

• mild to moderate pain
• neuropathic pain

Adverse:

• inc. risk seizure w/seizure disorder
• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 12

Naloxone

Answer 12

Receptor:
- U, d & K antagonist

Use:
- acute opioid overdose

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 13

Naltrexone

Answer 13

Receptor:
- U, d & K antagonist

Use:
- opioid & alcohol addiction

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 14

Dextrometorphan

Answer 14

Receptor:

Use:
- cough suppression, low dose

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 15

Diphenoxylate &

Loperamide

Answer 15

Receptor:
- U antagonist

Use:
- diarrhea (dec. SM motility intestinal wall)

Adverse:

• nausea
• vomiting
• sedation
• itching
• constipation
• urinary retention
• hypotension
• respiratory distress

Question 16

Opioid Mechanism of Action

Answer 16

• Activate receptors primarily located in brain & spinal cord involved in transmission & pain modulation
• U, d & K coupled
• Close Ca-channels presynaptically
• Close K channels postsynaptically
• Neural mechanisms:
• inhibit ascending pain transmission
• activate descending pain-inhibitory circuits
• Inhibit GABA receptors = enhanced pain inhibition