Opioid Drugs Flashcards
What do opioids do overall?
Decrease conduction
Prevent centralisation
What are the 3 classification of opioids?
Naturally occurring
Semi-synthetic
Synthetic
What is examples of naturally occurring?
Morphine
Codeine
What are examples of semi-synthetic?
Diamorphine (heroin)
Oxycodone
What are examples of synthetic?
Fentanyl
Methadone
What are the 3 opioid receptors?
MOP = most affected
DOP
KOP
What parts of the NS does morphine act on?
Nociceptors
Spinal cord
Supraspinal
Limbic system
What are the pharmacological effects of opioids?
Sedation
Depression of respiration
Cough suppression
Pupillary constriction
Nausea + vomiting
GI symptoms
Why are opioids cough suppressants?
Suppress “cough centre”
Describe mechanism of action
Activation of peripheral nociceptive fibres
= release of substance P + pain-signalling neurotransmitters
Neurotransmitters regulated by exogenous opioid agonists
= by inhibiting substance P release
What is the binding of an opioid agonist?
G-protein coupled receptor
What are their common side effects?
Drowsiness
Dizziness
Nausea
Constipation
Itching
Breathing slows
What are their long term side effects?
Sleep apnoea
Hormone imbalance
Physical dependence
Tolerance
Addiction
Overdose
Opioid-induced hyperalgesia
Describe how morphine tolerance happens
Increase in Ca2+
= kinase activation following MOR receptor activation
= remove Mg2+ block of NMDA receptor
= morphine tolerance
Describe how to stop morphine tolerance
Decrease activation of pronociceptive processes
= NMDA receptor antagonists
= reduce hypersensitivity
= improve analgesic efficacy of morphine
