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14 Cards in this Set
- Front
- Back
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what is the cause of death in opioid overdose?
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respiratory failure
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activation of opioid receptors:
mu: kappa: delta: where are opioid-Rs mostly located? |
mu: analgesia, resp depression, miosis, reduced GI motility, euphoria, sedation (most of morphine's actions)
kappa: similar to mu delta: binds leu-enkephalin. All are associated with Gi (thus lower cAMP) or K channel efflux (hyperpolarize cell); both limit NT release and response -mostly in CNS and GI tract |
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how does morphine block pain?
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causes IPSP in pain sensory neurons. also inhibits the inhibitor of, thus stimulating descending neurons which normally inhibit ascending pain transmission.
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how long will morphine remain in the plasma?
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3 hours
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what is the most efficacious opioid agonist?
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morphine, fentanyl, as well as most others, all have very high efficacy. however, some may be much more potent, eg fentanyl.
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how does meperidine relate to morphine?
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more rapid onset, shorter duration.
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how do diphenoxylate and loperamide relate to morphine?
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they are insoluble, act mainly only in GI to reduce diarrhea and GI secretions and motility. obviously they are only oral
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how is methadone dif than morphine?
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better oral uptake. it remains in plasma longer than morphine
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how does propoxyphene relate to morphine?
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very low potency. can lead to pulmonary edema. often combined with aspirin. not for severe pain
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what are the two opioid-R antags? difs
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naloxone - IV
naltrexone - oral, longer duration |
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list two mixed opioid agonist/antag. what are their use?
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pentazocine (agonist at kappa)
buprenorphine (agonist at mu) -both can be used as an analgesic in someone naive to opioids -used to produce withdrawal in an opioid abuser |
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discuss dif mechanisms to treat opioid dependence
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Methadone (either acutely, with a gradual reduction, OR in very high doses, leading to cross-tolerance, reducing the psychological dependence on heroin)
-or using antagonists, Naltrexone , or partial agonists, buprenorphine, which will lead to more violent, yet more quickly resolved withdrawal episodes |
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signs of opioid overdose
signs of withdrawal, will also occur on antagonist-precipitated withdrawal |
overdose: miosis, constipation, sedation, resp depression, no cough reflex
-withdrawal: mydriasis, diarrhea, hyperventilate, anxiety, |
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would meperidine be a good choice for helping wean a chronic opioid abuser?
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no, it has a shorter duration than morphine. the better choice is methadone, which has a longer duration
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