uterine drugs Flashcards
During pregnancy what hormone is of more abundance?
Progesterone> estridiol
What is the hormone of greater abundance during labor?
Estradiol> progesterone
What are the affects of high progesterone and low estridiol?
1. progesterone causes hyperplasia of the myometrium Decrease andenergic receptors Inhibits oxytocin receptor synthesis Inhibits estrogen receptor synthesis Promotes storage of prostaglandins
What are the physiological affects of estridiol>progesterone?
- Increases oxytocin receptors
- promotes cervical ripening
- Increase local prostaglandin release from the placenta cause myometrial contractions
what causes the stimulation release of oxytocin? What are the effects during labor?
Prostaglandins
- causes stronger myometrial contractions
What else induces the release of oxytocin?
Uterine contractions
- thus positive feedback
What tissues does oxytocin affect?
Breast and uterus
- causes smooth muscle contractions
What 2ndary pathway does oxytocin act through?
Binds to G-protein coupled receptor (OTR)
- causes increase in Phospholipase C
- leads to influx of Ca2+
- Release of Calcium from SR
Where are OTR’s found?
Myoepithelial cells of mammillary glands
Preggers myometrium
CNS
What affect does oxytocin have in relationships?
Release during orgasm
- needed for bonding with mates
what is the drug of choice for labor induction?
Pitocin
what and when is pitocin used?
Speed up labor for HTN and pre-eclampsia
- post due date
- augment labor
what can one give to reduce uterine contractions and how?
Indomethacin
- reduced Prostaglandins
What affect does Prostaglandins have on the cervix?
Ripens it
- cervix thins, softens and relaxes and dilates in response to uterine contractions
Thus ahat drugs can be used to ripen cervix as well as abortifacients?
Dinoprostone
Misoprostol
What are dinoprostone and minoprostol commonly used for?
Hydrataform mole
What are the PGF2a and what are they used for?
Dinoprost
Carboprost
- induce labor and abortifacient
What are ergots and where do they come from?
Alkaloids of fungus from rye, wheat and other cereal grasses
What is the MOA of ergots?
potent smooth muscle stimulator
what type of ergot mediates uterius contraction?
erognovine
Ergometrine
How does ergots and oxytocin and prostaglandins lead to reduction of uterine bleeding?
Contraction of the uterus leads to constriction of the blood vessels
What ergot leads to contraction of blood vessels?
Ergotmine
What are tocolytics?
any drug used to suppress uterine smooth muscle contraction and there by suppress premature labor
What is the MOA of tocolytics?
selective B2 agonists
- activate adenylyl cyclase and raise cAMP levels which interfere with myosin light chain kinase
- Gs pathway