Opioids Flashcards
Through what method of relieving pain do opioids work?
Modulate central pain awareness
What is the source of opioid analgesics?
Seed pods of the opium poppy
What are 2 principal alkaloids of opioid analgesics?
- Morphine
2. Codeine
What are the 2 classifications of opioids?
- Full agonists (strong)
2. Partial agonists (weak)
Name 2 places where natural opioids occur
- Juice of the opium poppy
2. Endogenous endorphins
What 2 ways can opioids be prepared if they are not natural?
- Prepared from morphine to form semisynthetic opioids e.g. heroin
- Synthesized from precursor compounds to form synthetic opioids e.g. fentanyl
Name 8 primary pharmacological effects of opioids
- Sedation / Anxiolytic
- Depression of respiration
- Cough suppression
- Pupillary constriction
- Nausea and vomiting
- GIT symptoms
- Release histamines causing allergic reaction
- Affect white blood cell and immune function
What 4 ways is the sedation effect of opioids seen?
- Drowsiness
- Apathy
- Cognitive impairment
- Sense of tranquillity
What is the main life threatening pharmacological effect of opioids?
Depression of the respiratory system, especially if opioids taken with alcohol
How do opioids affect the GIT?
Cause constipation
Give an overview of an opioid’s mechanism of action
Act presynaptically to inhibit substance P release, which is caused by activation of peripheral nociceptive fibres and other pain-signalling neurotransmitters from nerve terminals in the dorsal horn of the spinal cord
What is the target of opioids?
G-protein coupled opioid mu receptors in the CNS and PNS
What is the cellular effect of opioids agonising G-protein coupled opioid mu receptors?
- Closure of calcium channels on the presynaptic membrane
- Opening of potassium channel on postsynaptic membrane
Name 3 opioid pain receptors
- Mu
- Kappa
- Delta
What are 2 types of mu receptors?
- Mu-1
2. Mu-2
What is the location and function of Mu-1 receptors?
Located outside spinal cord and responsible for central interpretation of pain