Monday - Uterine Drugs - Trachte Flashcards
Drugs that promote labor
Oxytosin (ptosin)
PGE - Dinoprostone, Misoprostol
Ergots - Ergonovine, Ergotamine (less blood loss after birth bc vasoconstriction)
Why does ptosin only work in last trimester
Estrogen upregulates oxytosin receptors and it’s high at the end of pregnancy
Drugs that suppress labor (tocolytics)
terbutaline - beta2 ag
magnesium sulfate
oxytosin receptor antagonist - atosiban
indomethacin - nsaid
What do tocolytics do
suppress uterine muscle contraction
What type of receptors cause smooth muscle contraction
Gq –> PLC–> IP3 –> Ca
Oxytocin structure
released from where
synthesized where
similar to ADH
from posterior PIT
made in paraventricular and supraoptic nuclei in hypothal
Why does Oxtocin work faster than thyroid hormone?
it doesn’t cause transcription
What inhibits oxytocin release
ethanol
what is oxytocin used for pharacologically
promotes uterine contractions (in3rd tri)
milk production
ADH like effects at high levels (similar structure)
kinetics of oxytocin
can’t give orally bc it’s a peptide
half life 12 minutes
degraded by oxytocinase from uterus and placenta
contraindications of oxytocin
big baby
already having uterine contractions
if previous c section, risk of uterine rupture
Protaglandins use in pregnancy
abortions
PGE2 contracts the uterus (also causes menstrual pain)
Prostaglandin drugs
Dinoprostone - natural PGE
misoprostone - synthetic PGE (use w/ mifepristone)
dinoprost - natural PGF2
carboprost - PGF2, can use in anytrimester
Ergots cause what
when do you se them?
vasoconstriction
- contarcts uterus. stops post partum bleeding. MOA - 5HT2 and adrenergic and dopanergic
after labor bc high fetal mortality
which adrenergic receptor is used by tocolytics (stop labor)
Beta 2 (terbutaline Gs -->cAMP --> inactivates MLCK (which normally phosphorylates myosin to cause contraction)
also increases heart rate –> increase O2 demand –> MI
