Opioid drugs Flashcards
What are opioids
They are substances which act at opioid receptors in rtes central and peripheral nervous system
Name the 3 families of naturally occurring opioids
- Beta-endorphins
- Enkephalins
- Dynorphins
What are opioids also known as
neuropeptides” aka “endogenous endorphins”
When were opioids discovered
in the 1970s
What properties do endorphins have
They have morphine like properties
What are endorphins responsible for
Responsible fro the feelings of euphoria elicited from physical or emotional pleasure, pleasure or stress
What are endorphins described as
Natural painkillers that are very potent
What roles do opioids play
Selective roles in:
- Pain modulation
- Neurotransmission
- Stress responses
- Reward processing
- Autonomic function regulation
In which system do opioid act in
CNS and PNS at the pre and post synaptic membranes to trigger their responses
Name the 3 families of opioid receptors
- Mu
- Delta
- Kappa
Where are Mu receptor found
Found in the brainstem and media thalamus
What do Mu receptors control
- Super spinal analgesia,
- respiratory depression
- Euphoria
- Sedation
- Decreased GIT motility
- Physical dependence
Where are delta receptors found
In the brain
Where are kappa receptors found
In the limbic system, diencephalon, brainstem, spinal cord
What are Kappa receptors responsible for
- Spinal analgesia
- Sedation
- Dyspnoae
- Dependence
- Dysphoral
- Respiratory depression
Describe all opioid receptors
They are G protein couples
What do opioid receptors cause
cAMP inhibition at intracellular targets which then act as second messenger to activate protein kinases and affect gene transcription
How do opioid receptors act on presynaptic membranes of A delta and C fibres neurones
They will inhibit voltage gated calcium channels decreasing cAMP levels blocking the release of pain transmitters like glutamate, substance p and calcitonin with the end result being analgesia
Name the 4 chemical classes of opioids
- Phenanthrenes
- Benzomorphans
- Phenylpiperidines
- Diphenylheptanes
Give examples of Phenanthrenes
- Morphine
- Codeine
- hydromorphone
- Oxycodone
- buprenorphine
Describe morphine
Is a hydroxyl containing opioid which has a higher incidence of nausea and hallucinations
Descrive codeine
Is a hydroxyl containing opioid which has a higher incidence of nausea and hallucinations
Give examples of Benzomorphans
Pentazocine
Give examples of Phenylpiperidines
- fentanyl,
- alfentanil,
- sufentanil,
- meperidine
Give examples of Diphenylheptanes
propoxyphene and methadone
Name the one opioid drug that is unique
Tramadol
Why is Tramadol unique
It doesn’t fit into the standard opioid classification system