B7.005 Prework 3: Opioids Flashcards

1
Q

what is an opioid

A

any drug, natural or synthetic that acts at opioid receptors

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2
Q

mu receptors

A

produce analgesic, sedative, and euphoric effects of opiates as well as side effects

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3
Q

delta receptors

A

contribute to analgesia at spinal levels

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4
Q

kappa receptors

A

may contribute to analgesia, but primarily result in dysphoria

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5
Q

action of opioid drugs at the different receptors

A

various opioid compounds have different affinities for these sites and may be full or partial agonists, antagonists, or have mixed activity

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6
Q

clinical uses of opioids

A

analgesics
cough suppressants
antidiarrheal

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7
Q

where are opioid receptors located

A

brain
spinal cord
various peripheral tissues

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8
Q

CNS pharmacological effects of prototype drug: morphine

A
analgesia
euphoria/dysphoria
sedation
resp depression
cough suppression
miosis (parasympathetic activation)
truncal rigidity (impairs ventilation)
nausea and vomiting
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9
Q

peripheral pharmacological effects of prototype drug: morphine

A
arterial and venous dilation
decreased gut motility (constipation)
biliary colic (cholinergic)
decreased renal blood flow
decreased uterine tone
endocrine alterations
-increased ADH, PRL, somatotropin
-decreased LH
histamine release
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10
Q

toxicity of opioids

A
resp depression (primary cause of death)
dysphoria 
nausea and vomiting
constipation
seizures
tolerance / withdrawal / addiction
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11
Q

important differences between opioid drugs

A

potency
efficacy
duration of action
oral bioavailability

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12
Q

equianalgesic dose

A

equal to 10 mg morphine

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13
Q

low efficacy opioids

A

low efficacy for analgesia and produce only “side effects”
don’t cross the BBB
used as anti-diarrheals

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14
Q

high efficacy analgesic opioids

A
used for severe pain (trauma, post surgical, MI)
morphine
methadone
meperidine
fentanyl
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15
Q

morphine

A

prototype drug
poor oral bioavailability due to 1st pass effect
duration: 4-5 hours
hepatic metabolism, renal excretion

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16
Q

morphine metabolite

A

glucuronidated metabolite M-6G is even more potent, but has poor BBB penetration

17
Q

methadone

A

longer acting than morphine: 6 hrs, plasma t1/2 24 hr
good oral bioavailability
used as maintenance in addicts, but also for pain

18
Q

meperidine

A

duration: 2-4 hr
antimuscarinic > may cause tachycardia
metabolized to an active metabolite that is psychoactive and can cause seizures

19
Q

fentanyl

A
short acting
duration: 1-1.5 hr
100x more potent than morphine
primarily acts at mu receptors
poor oral bioavailability
transdermal available
20
Q

low to medium efficacy analgesic opioids

A

administered orally
used for moderate pain (broken bones, dental procedures)
often formulated with aspirin, APAP, or ibuprofen
codeine
hydrocodone
oxycodone
tramadol

21
Q

codeine

A

low efficacy
metabolized to morphine by CYP2D6
ineffective in people with decreased enzyme levels

22
Q

hydrocodone

A

moderate efficacy

23
Q

oxycodone

A

moderate-high efficacy
available in ER formation
high levels of addiction (esp with ER)

24
Q

tramadol

A

low efficacy
also inhibits NE and 5HT reuptake
may have efficacy for neuropathic pain

25
partial agonist or mixed agonist-antagonist analgesic opioids
believed to have less addictive potential and risk of resp depression used for moderate to severe pain used for opioid addiction
26
buprenorphine
mu partial agonists
27
pentazocine
kappa agonist | mu partial agonist or antagonist
28
antidiarrheal opioids
poor permeation of the BBB diphenoxylate loperamide (OTC) eluxadoline
29
eluxadoline
mu and kappa agonist delta antagonist used for IBD with diarrhea
30
antitussive opioids
poor permeation of the BBB codeine dextromethorphan (OTC)
31
opioid drug of abuse
heroin | no medical uses
32
opioid antagonists
naloxone naltrexone reverse the effects of opioids after overdose prevent opioids from having an effect can induce withdrawal when administered IV or in high dose
33
naloxone
IV | intranasal
34
naltrexone
oral | depot injection
35
opioid antagonists for constipation
poor BBB penetration increase risk of bowel perf -methylnaltrexone (subQ) -naloxegol (oral)
36
contraindications / interactions associated with opioids
head injuries -vasodilation can increase intracranial pressure pregnancy -fetal addiction, sedation impaired pulmonary function (except acute pulmonary edema) hepato- or renal compromised patients increased sedation and resp depression with sedatives or antipsychotics