Uterine Drugs Flashcards
What is a tocolytic?
Reduces uterine contractility -> suppresses preterm labor
Prostaglandin drug examples and which PG they mimic (3)
PGE: dinoprostone and misoprostol
PGF2a: dinoprost
Oxytocin drug (1)
Pitocin
2 Ergots
Ergonovine & Ergotamine
4 tocolytics and their classes
Terbutaline (b2 agonist), Magnesium Sulfate, Atosiban (Oxytocin receptor antagonist), Indomethacin (NSAID)
MOA and uses of oxytocics
Stimulate uterine smooth muscle contraction e.g. induce labor, control postpartum hem or atony
What intracellular second messenger stimulates Ca release from the SR?
IP3
How is [Ca] regulated (decreased) in the cell
Na-Ca antiporter utilizes Na gradient set up by Na-K ATPase to kick Ca out of cell
What happens to muscle below the Ca threshold?
Myosin light chains are dephosphorylated by MLC phosphatase -> relax
What are neurophysins, and how do they come into play?
Oxytocin and ADH carrier proteins, released from posterior pituitary with the hormones
3 triggers for oxytocin release
Cervical dilation, mechanical stim of vagina or uterus, suckling reflex
What type of receptor is the oxytocin receptor (OTR) and where is it found (3)
GCPR w phospholipase C. Found in 1. myoepithelial cells of mammary gland 2. pregnant myometrium esp late 3. CNS
What substance is an inhibitor of oxytocin release?
Alcohol
What is the caveat of oxytocin stimulating uterine contractions
Only works well during 3rd trimester of pregnancy
At high concentrations, OT can do what???
Act like ADH –> antidiuretic + vasoactive
OT being a peptide means what pharmacologically?
Can’t be given orally
Oxytocin removal by
liver or kidney