Opioids Flashcards
2 opioids used for diarrhea
1) loperamide
2) diphenyoxylate
lack analgesic effects at usual doses
coanalgesic for neuropathic pain
imipramine
meperidine AE
large doses given in short intervals - seizures, mydriasis
meperidine = short t 1/2 BUT its metabolite = normeperidine has a t 1/2 of 15-20 hours
fentanyl is metabolized by
CYP3A4
which opioids are metabolized by CYP2D6
codeine (used CYP2D6 to convert to morphine)
oxycodone
hydrocodone
combination of which two opioid types can cause withdrawal sxs
pure agonist + weak partial agonist - risk of diminishing analgesia OR inducing withdrawal
what is meperidine contraindicated with
MAOI, serotinergic agents
- meperidine can block reuptake of serotonin
what is tramadol contraindicated with
MAOI
epileptic patients: inc risk of seizures in pt with seizure disorders and those taking medications that lower seizure threshold
what are opioids contraindicated with
1) sedatives
2) anti psychotics
what clinical conditions are opioids contraindicated with
impaired: pulmonary, renal, liver, adrenal function
pregnancy
head injuries
opioids for severe pain
1) morphine
2) heroine
3) oxycodone hydrocodone
methadone AE
QT prolong - torsades
death
tramadol contraindications
serotinergic drugs –> serotonin syndrome
tramadol use
neuropathic pain
tramadol MOA
weak mu agonist AND NE/serotonin reuptake inhib
methadone MOA
strong mu agonist, NMDA antagonist, serotonin/NE reuptake inhibitor
pentazocine
mixed agonist and antagonist opioid
kappa agonist, mu antagonist/partial agonist
butorphanol
mixed agonist and antagonist opioid
kappa agonist, mu antagonist/partial agonist
nalbuphine
mixed agonist and antagonist opioid
kappa agonist, mu antagonist/partial agonist
buprenorphine
mixed agonist and antagonist opioid
partial mu agonist, kappa antagonist
ceiling effect in which drugs
1) pentazocine
2) butorphanol
3) nalbuphine
4) buprenorphine
mixed agonist and antagonist opioids AE
all cause psychomimetic effects except: buprenorphine
mixed agonist and antagonist opioids use
to reduce addiction potential of opioids
- potent in opioid naive pt
- can precipitate withdrawal in pt who are already physically dependent
buprenorphine use
management of opioid addiction
psychomimetic effect is uncommon
partial mu agonist and kappa antagonist
naloxone
used in tx of opioid OD
opioid antagonist at mu, delta, kappa receptors
naltrexone
used for opioid addiction – dec alcohol craving
opioid antagonist at mu, delta, kappa receptors
antitussives (2)
dextrometorphan
codeine
which receptors to antimotility opioids work at
mu and delta receptors on enteric nerves, epithelial cells, and muscle
topical and blocks VG sodium channels
lidocaine
loperamide and diphenoxylate act on which receptors
mu and delta on enteric nerves, epithelial cells, muscle
which drug decreases craving for alcohol in chronic alcoholics?
naltrexone
which drug is preferred for managing opioid withdrawal?
methadone
what makes methadone a good drug for managing opioid withdrawal
long t 1/2 = abstinence syndrome is prolonged BUT less severe
less profound sedation
euphoria
methadone vs morphine
equal in potency
less euphoria, longer duration
fentanyl MOA
mu agonist
rapid onset/short duration
100x more potent than morphine
meperidine MOA
mu receptor agonist
not recommended b/c of metabolite toxicity
heroin MOA
hydrolyzes to 6-MAM –> then to morphine
heroin vs morphine
heroin and its metabolite (6-MAM) more liposoluble than morphine = enter brain more readily
morphine MOA
strong agonist of mu, delta, kappa
high affinity at mu
low affinity at delta and kappa
which drugs are hydrolyzed by tissue esterases
heroin
remifentanil
opioid metabolism
convert to glucuoronides = excretd by kidneys
morphine conjugated
morphine-3-glucoronide = neuroexcitatory
also conjugates to M6G = more potent than morphine
ingestion of toxic doses of mu agonists presents with
pinpoint pupils - d/t PS excitation
where are mu receptors located
peripheral terminals of sensory neurons
opioids MOA
close VG Ca2+ channels of PRESYNAPTIC NT and open K+ on POSTSYNAPTIC neurons
receptors associated with supraspinal analgesia
mu, kappa, delta
receptors associated with spinal analgesia
mu, kappa, delta
receptors associated with respiratory depression
mu
receptors associated with dec GI motility
mu, delta
receptors associate with psychotomimesis
kappa
receptors associated with sedation
mu, kappa
G protein associated with opioid receptors
G(i)