Opioids Flashcards
Describe the major opioid receptors in the following regards:
- neuron expression
- tissue expression
- fxn
DELTA
- pre-synaptic
- brain
- analgesia, sedation, dependence
KAPPA
- pre-synaptic
- brain, spinal cord
- spinal analgesia, sedation, miosis, inhibition of ADH, dysphoria
MU
- pre- and post-synaptic
- brain, spinal cord, GI
- supraspinal analgesia, respiratory depression, miosis, euphoria, reduced GI motility, dependence
NOCICEPTIN
- brain, spinal cord
- anxiety, depression, appetite
Describe the effects of opioid receptor agonists on the response to pain. Describe the MOA by which opioid receptor activation promotes analgesia.
MOA - inhibit pain pathway at various levels (peripheral tissue, spinal cord, or cortex)
- presynaptic (mu, kappa, delta) => decreased Ca2+ influx, increased K => decreased transmitter release
- postsynaptic (mu) => increase K conductance => increase IPSP
Describe the following for morphine:
- MOA
- indications
- side effects
MOA
- mu receptor agonist
INDICATION - severe analgesia
- prototype
SIDE EFFECTS
- constipation
- addiction
- tolerance (desensitization, downregulation)
- withdrawal
- overdose (antidote = naloxone)
Describe the following for meperidine:
- MOA
- indications
- side effects
MOA
- k receptor agonist
- also bind to K channels, dopamine receptors, and muscarinic receptors
INDICATION - analgesia (strong)
SIDE EFFECTS
- due to metabolite norpethidine
- serotonin syndrome
- seizure
- dysphoria
- tremor
- respiratory depression
- CANNOT be countered by naloxone
Describe the following for codeine:
- MOA
- PD
- indications
- side effects
- drug interactions
MOA
- mu receptor agonist
INDICATIONS
- moderately strong analgesic
- cough suppressant
- diarrhea
- IBS
- narcolepsy
SIDE EFFECTS
- euphoria
- itching
- urinary retention
- depression
- constipation
- erectile dysfunction
- withdrawal
NOTE: active metabolite is codeine
Describe the following for naloxone:
- MOA
- indications
- side effects
- drug interactions
MOA
- mu, kappa, delta ANTagonist
INDICATIONS
- antidote
SIDE EFFECTS
- change in mood
- trembling
- change in heart rhythm
- blocks endorphine action
NOTE
- overdose can come back once naloxone wears off b/c the opioid is still around the system
Describe the CNS effects of opioids.
- analgesia of sensory and emotional pain
- euphoria (sometimes dysphoria)
- sedation
- cough suppression (maintain ventilation during endotracheal intubation)
- miosis
- temperature
- respiratory depression
List the opioids that belong in each category:
- strong
- moderately strong
- receptor agonist-antagonist
- antagonist
STRONG
- morphine
- methadone
- meperidine
MODERATELY STRONG
- codeine
- oxycodone
AGONIST-ANTAGONIST
- pentazocine
- buprenorphine
ANTAGONIST
- naloxone
Describe the following for hydrocodone:
- MOA
- indications
- side effects
- drug interactions
MOA
- mu receptor agonist
- delta receptor agonist
INDICATION
- moderate analgesic (moderately strong)
- cough suppression
SIDE EFFECTS
- sleepiness
- respiratory depression
- constipation, N/V
- loss of consciousness
- miosis
- overdose
DRUG INTERACTIONS
- can be combined with aspirin or ibuprofen for enhanced effect
How do opioids lead to euphoria?
- opioid binds to mu receptor
- inhibits release of GABA
- GABAb receptor is not inhibited =>
- release of dopamine
Describe the following for pentazocine:
- MOA
- indications
- side effects
- drug interactions
MOA
- mu antagonist
- kappa agonist
- delta agonist
INDICATION
- analgesic
- dental extraction
SIDE EFFECTS
- weak antagonist of morphine and meperidine
- hallucinations
- psychotomimetic effects
- CV effects
- withdrawal
Describe the following for methadone:
- MOA
- indications
- side effects
- drug interactions
MOA
- mu agonist
- delta agonist
- decreased desire for opioid intake
- inhibitory effect that stops withdrawal manifestation
INDICATION
- partial treatment of opioid dependence
- used in heroin addicts (high lasts longer, less societal damage)
Describe opioid overdose.
- sedation
- stupor, coma
- decreased HR, blood flow
- cough suppressant
- respiratory depression
- hyperventilation
- constipation, N/V
- loss of sexual interest
