pharmacology: opioids Flashcards
effects of morphine
- analgesia (increase pain tolerance and decrease -perception/reaction to pain)
- sedation
- respiratory depression
- vasodilation
- smooth muscle (longitudinal relaxes and circular contricts)
- cough suppression
- nausea and vomiting (stimualtion of chemoreceptor trigger zone)
- increase histamine release
what are the effects of morphine on smooth muscle
longitudinal relaxes and circular constricts causing :
GI: decreased peristalsis, constipation, cramping
GU: urinary retention and urgency to void
Biliary: increased pressure
Pupils: miosis
what can be used to avoid cramping with opiods?
antimuscarinic (atropine)
opiod mechanism
presynaptic and postsynaptic inhibition through Gi coupling (decreased cAMP)
-endorphins effects mu receptor
what is the prototype for mu agonist?
morphine
what are the full agonists of mu?
morphine, meperidine, methadone, fentanyl, codeine (weak), heroine lol
meperidine use
since an antimuscarinic as well - NO MIOSIS, tachcardia, NO spasm GI/GU/gallbladder
side effect of meperidine
metabolized by chtochrome P450 to normeperidine which is a serotonin reuptake inhibitors - may cause serotonin syndrome and seizures
methadone use
maintenance of opiate addict (long long halflife)
codeine use
cough suppressant and analgesia
what is the partial opiod agonist? what does it cause?
buprenorphine - causes precipation of withdrawal
what are the mixed agonists/antagonist opiods? mechanism and uses?
nalbuphine and pentazocine
kappa agonist for spinal analgesia and dysphoria
mu antagonist causing precipitation of withdrawal
what are the opiod antagonists
naloxone, naltrexone, methylnaltrexone
naloxone use
IV - reversal for respiratory depression
naltrexone use
PO causing decreased craving for alcohol and used in opiate addiction
methylnatrexone use
treatment for opioid induced constipation (does not cross BBB and won’t precipitate withdrawal)
side effects of opioids
acute toxicity: pinpoint pupils, respiratory depression, coma
management of acute toxicity of opioids
supportive and IV naloxone
tolerance of opioids
pharmacodynamic (NOT RECEPTOR - but increased cAMP signal transduction)
NO TOLERANCE TO MIOSIS AND CONSTIPATION
withdrawal symptoms of opioids
yawning, lacrimation, rhinorrhea, salivation, anxiety, sweating, goose bumps, muscle cramps, spasms, CNS-originating pain
management of opioid withdrawal
supportive, methadone, clonidine (alpha 2 agonist - taper down withdrawal symptoms by canceling sympathetic flare up)
what opiate-related drug is used for treatment of diarrhea?
loperamide
what opiate-related drug is used for treatment of cough?
dextromethorphan
