Analgesics 3: Opioids Flashcards
(20 cards)
Opioids
what does the change in functional groups display in heroin and morphine do?
they serve to decrease the time of onset of effect
opioids
what awre 4 semi-synthetic opioids
- heroin
- codeine
- oxycodone
- diamorphine
opioids
what type of opioid drug is Naloxone
naloxone is an opioid receptor antagonist
opioids
what are 4 synthetic opioids
- pehtidine
- fentanyl
- methadone
- buprenorphine
opioids
what are the 4 opioid receptors opioids act on
- µ
- δ
- κ
- NOP (ORL1)
analgesic action of opioids
via what opioid receptor does analgesic action occur?
occurs through µ opioid receptors
analgesic action of opioids
where can µ receptors be found in the body and thus where can opioids provide analgesic action
can be found:
- in periphery
- in spinal column
- supraspinal areas (I.e brain)
analgesic action of opioids
what are opioids useful for and what are they not useful for
- acute pain
- “end of life” pain
- not useful for neuropathic or chronic pain
analgesic action of opioids
what type of receptors are opioid receptors and what does this lead to
g-protein couple receptors
- specifically coupled to Gi protein
- leads to decreased cAMP and increase in potassium conductance, which leads to decreased neurotransmitter release
opioids
what are 4 other uses of opioids other than as analgesics
-sedation
-treatment of diarrhoea
- anti-tussive (stops coughing)
- treament of opioid addictions
opioid- potencies
what are the weak opioids?
tramadol
codeine
opioids
what are the strong opioids
methadone
buprenorphine
fentanyl
opioid- adverse effects
what are 11 unwanted effects of opioids
think: MORPHINE SCT
- Miosis
- Orthostatic hypotension
- Respiratory depression
- Pain suppression/Pruritis
- Histamine release
- increased intracranial tension
- Nausea
- euphoria
- sedation
- constipation
- tolerance
opioids- codeine vs morphine
what molecule converts codeine to morphine
the isoform of CYP called CYP-2D6
opioids - codeine vs morphine
what are the 2 phases of metabolism that allow codeine to become an active opioid?
Phase 1: metabolism of codeine via CYP3A4 and CYP2D6 (this one mainly)
Phase 2: metabolism of the newly converted morphine via glucuronyl transferase (UGT) to make morphine more water soluble
opioids- codeine vs morphine
how are all forms of bioactive converted codeine excreted
renal excretion
Opioids - Tramadol
what is the dual action of Tramadol
- opioid receptor agonist
- Noradrenaline and 5HT reptake inhibitor
Opioids - Tramadol
what is tramadol metabolised by?
- CYP2D6
- CYP2B6
- CYP2A4
opioids - Tramadol
where does tramadol act and what is its potent metabolite?
- active at µ receptors
- potent metabolite: O-desmethyl-tramadol
Principles of Drug therapy
what are the 7 principles of drug therapy regarding analgesics
- continous pain requires continuous relief
- use oral route when possible
- parenteral route if vomiting or dysphagia occurs
- dose for each patient should be individually determined
- reassess pain at each change of analgesia
- explain each change of mediation and reassure patient
- follow the analgesic ladder
