9.2: Narcotic Analgesics Flashcards
What neurotransmitter do opioids inhibit the release of?
Substance P
What neurotransmitter is released by interneurones involved in the descending inhibitory control of pain?
GABA
What ascending tract carries pain?
Lateral spinothalamic tract
What is the name of the area of the spinal cord that contains many opioid receptors?
Substantia gelatinosa
What type of receptors are opioid receptors?
GiPCRs
What is the effect of an opioid receptor being stimulated?
Aims to reduce release of neurotransmitter substance P across the synaptic cleft so less pain signal is propagated to the brain
(Reduce Ca influx, increases K efflux, reduces cAMP synthesis)
What type of opioid receptor are there?
u (mew)
d (delta)
k (kappa)
What are some ADRs of opioids?
Nausea Constipation Vomiting Miosis (pin prick pupils) Respiratory depression Drowsiness Hypotension Confusion Psychosis
Tolerance!
What is an example of a partial opioid agonist?
Buprenorphine
What is an opioid antagonist and when would it be indicated?
Naloxone
Can reverse opioid overdose
Why is morphine and diamorphine given IV?
As it is not very lipid soluble so has low oral bioavailability
What opioid is used in maintenance of opioid dependence?
Methadone
Has a very long half life so given once a day and has good oral bioavailability so stops them from infecting
What are all opioids metabolised to?
Morphine
What is a very potent opioid that can be used in anaesthetics?
Fentanyl
Which opioid receptor is involved in mediating most of the therapeutics effects of opiates?
The mew receptor, u
