OPIODS DRUGS-- Morphine Flashcards
how many receptors are there for opiods?
3
mu
kappa
delta
what nociception in mu involved in?
Thermal
chemical
mechanical
what nociception is kappa involved in?
thermal
chemical
what process is delta involved in?
interaction with enkephalins
what type are all three of them
g protein coupled receptors— inhibits adenylyl cyclase
what is their effect on ion channels
post synaptic potassium efflux that causes hyperpolarization
presynaptic calcium influx is inhibited that decreases the release of NT such as glutamate
what is the prototype strong mu receptor agonist?
morphine
what is the prototype weak agonist
codeine
which points does morphine acts on the mu receptors?
CNS
GI TRACT
URINARY TRACT
does morphine acts on the kappa receptor?
yes
in the dorsal horn 1 and 2 of the spinal cord
by what other effects does morphine exert its effect by?
by inhibiting the release of substance P
also inhibits release of many excitary NT’s
how does morphine produces analgesia?
by altering the perception of pain in the brain
by inc pain threshold in the spinal cord
how does morphine produce euphoria?
by disinhibiting of dopamine containing neurons in the ventral tegmental area
effect on respiration?
resp depression— dec sensitivity to co2 for resp center neurons
how can morphine be used diagnostically?
It causes miosis– pinpoint pupil— users of morphine do not develop tolerance to this effect
effect on gi
constipation
effect on cvs
at lower doses– no major effect
at higher doses– dec HR, dec BP
which phase of labor does it act on
prolong the second phase
effect on mast cells
histamine release— urticaria, vasodilation
can also cause bronchoconstriction— so with caution in asthma pts
effect on hormones
growth hormone release is inc
inc ADH— URINARY RETENTION
MODE OF ADM
AS it has a significant 1st pass— so IV, SC, IM are mostly preferred
orally for extended release
metabolites
M3G— no analgesic action but neuroexcitary
M6G— 2 to 4 times more potent than morphine —- resp depression
adrs ( common with almost all opiods)
hypotension
dysphoria
sedation
constipation
urinary retention
resp depression
inc intracranial pressure( with morphine mostly— with caution in pts with head injury)
tolerance
rep use— tolerance to — resp dep, analgesia, euphoria, sedation
not tolerance to — pinpoint, constipating effects
