opioids Flashcards
endogenous opioid peptides
enkephalins endorphins dynorphins
endogenous ligands for mu receptor
enkephalins, B-endorphin
drug ligands for mu receptor
morphine, fentanyl, methadone, meperidine, buprenorphine
endogenous ligands for kappa receptor
dynorphins
drug ligands for kappa receptor
butorphanol, pentazocine, nalbuphine
endogenous ligands for delta receptor
enkephalins, B-endorphin
drug ligands for delta receptor
none
opioid pharmacology
analgesia, cough suppression, antidiarrheal effect/constipation, euphoria, sedation, respiratory depression, nausea, endocrine effects, pupillary constriction
mu agonist, low oral to parenteral potency ratio (3/4:1); IV/oral/sustained oral/suppository available, 4-5 hr analgesia
morphine
mild to moderate pain, some metabolized to morphine, often used with NSAID/acetaminophen
codeine
more efficacious than codeine, used alone for moderate to severe pain, available as sustained release oral
oxycodone
moderate to moderate/severe pain, usually combined with NSAID/acetaminophen, sustained release available
hydrocodone
diacetyl morphine, more lipophilic than morphine, converted to 6-mono-acetyl morphine and morphine
heroin
phenylheptylamine, mu agonist, equipotent with morphine, good oral availability, longer duration of action, used in treatment of opioid abuse and pain, long half life (a day)
methadone
phenylpiperidine, shorter duration of analgesia, forms toxic metabolite that can accumulate, interactions with MAO inhibitors
meperidine
related to meperidine, mu agonist, 100X potency of morphine, short acting (1-1.5 hr), injectable, transdermal patches, soluble buccal film, used for conscious procedures
fentanyl
other opioid agonist, 2-3X potency of morphine
hydromorphone
mu antagonist, kappa agonist, similar in efficacy/potency to morphine, little euphoria, low abuse potential can precipitate withdrawal in opiate-dependent patients; only injection
nalbuphine
partial mu agonist, 25-50X greater potency than morphine, moderate to severe pain, transdermal patch available
buprenorphine
oral buprenorphine + naloxone used to treat opioid dependence
suboxone
antagonist w/ high affinity for mu receptor (less for K and D), parenteral > oral activity, short duration (1-2 hr), treatment of opioid overdoses, combined with opioids to decrease parenteral abuse liability, component of suboxone
naloxone
orally active with long half-life ( >24 hrs), used in treatment of alcoholism & opiate addiction, competitive antagonist
naltrexone
D-isomer of levorphanol, cough suppressant, also NMDA receptor antagonist
dextromethorphan
weak mu agonist activity, blocks NE and serotonin uptake, mild-moderate pain, oral, sustained release available
tramadol
clinical problems with opioids
respiratory depression, sedation, interactions with CNS-depressant drugs, constipation, nausea, vomiting, endocrine disturbances, tolerance to analgesic effect, physical dependence, abuse potential
tolerance to N/V vs miosis & constipation
rapid tolerance to nausea/vomiting, little to no tolerance to miosis and constipation
morphine withdrawal symptoms 6-12 hr
drug seeking behavior, restlessness, lacrimation, sweating, rhinorrhea
morphine withdrawal symptoms 12-24 hr
restless sleep, irritability, tremor, dilated pupils, anorexia, gooseflesh
morphine withdrawal symptoms 24-72 hr
increased intensity of symptoms, increased HR/BP, involuntary movements of arms and legs
morphine withdrawal symptoms later on
symptoms continue 7 to 10 days, alternating autonomic hyperactivity with brief periods of restless sleep delayed growth/devo in infants born to addicted mothers detected up to 1 year
treatment of opioid abuse
methadone, suboxone, naltrexone
