4.1 Opioids Flashcards
Activation of opioid mu receptors produces which effects? (4)
1) Euphoria
2) Respiratory Depression
3) Analgesia
4) Physiological Dependence
Delta and Kappa opioid receptors contribute to analgesia at which level?
Spinal
Opioid receptors couple to which G protein?
Gi
What is the action of opioids on presynaptic neurons?
Close voltage gated Ca2+ channels
What is the action of opioids on postsynaptic neurons?
Open K+ channels
The analgesic effects of opioids are due to which 2 abilities?
1) Inhibit ascending pain transmission
2) Activate descending pain-inhibitory circuits
The descending pain-inhibitory neurons are inhibited by what?
GABA(a)
What categories are the Opioid Analgesics classified into? (3)
1) Pure agonists
2) Mixed agonist-antagonists
3) Antagonists
How do pure opioid agonist act? (2)
1) High affinity for mu receptors
2) Lower affinity for gamma and kappa receptors
How do Mixed agonist-antagonist opioids act?
1) Agonist and antagonist act differently on different receptors
2) Analgesic ceiling effect
3) Some drugs cause psychomimetic effects
What are the CNS effects of opioid use? (8)
1) Analgesia
2) Euphoria
3) Sedation and drowsiness
4) Respiratory depression
5) Cough suppression
6) Miosis
7) Truncal rigidity
8) Nausea and vomiting
What is pathognomonic following toxic doses of mu agonist?
Pinpoint pupils (miosis)
What are the peripheral effects of opioid use? (6)
1) Hypotension
2) GI tract
3) Biliary tract
4) Genitourinary tract
5) Uterus
6) Pruritis
Opioids are converted to what? And excreted how?
- Glucuronides
- Excretion via kidney
What is morphine primarily conjugated to? And the smaller portion?
- Morphine-3-glucuronide (M3G) (primary)
- Morphine-6-glucuronide (M6G) (10%)
