Uterine Drugs Flashcards
Sm muscle contractile pathway
Gq-receptor mediated activation of phospholipase C IP3 formation release of calcium sm muscle contraction
Sm muscle relaxation pathway
Gs-receptor mediated adenylyl cyclase activated cAMP increased cAMP activates protein kinase A protein kinase A inactivates myosin light chain kinase contraction of sm muscle stops
Oxytocin receptors in myometrium
only present in myometrium during 3rd trimester
Oxytocin receptor type
Gq coupled receptor
Oxytocin
MOA
TU
Tox
MOA: bind oxytocin receptors, stimulate uterine contractions
TU: induction of labor, only in 3rd trimester when oxytocin receptors are present in myometrium
Tox: uterine rupture (prior Hx of C-sections), not to be used w/ hypertonic uterine contractions (will not help)
Prostaglandin receptors in sm muscle
Gq coupled receptors
usually PGE2 or PGF2α
Dinoprostone
MOA
TU
MOA: PGE2
TU: hydatiform mole
Misoprostol
MOA
TU
MOA: PGE1
TU: abortifacent, used w/ mifepristone (progesterone receptor antagonist)
Dinoprost
MOA
TU
MOA: PGF2α
TU:
Carboprost
MOA
TU
MOA: PGF2α
TU: abortifacent, labor induction
Ergonovine
MOA
TU
Tox
MOA: α-andrenergic, dopaminergic, 5HT2 receptors, ultimately induces uterine contractions -> blood vessel compression
TU: control post-pardum bleeding
Tox: not used before fetus is delivered
Ergotamine
MOA
TU
MOA: α-adrenergic, dopaminergic, 5HT2 receptors, ultimately causes cerebral vasoconstriction
TU: migraines
Magnesium sulfate
MOA
TU
MOA: competes w/ Ca2+ for binding sites in sm muscle cells, prevents sm muscle contraction
TU: prevents seizures associated w/ eclampsia
Terbutaline
MOA
TU
Tox
MOA: β2 agonist
TU: prevent/stop contractions
Tox: tachycardia (non-selective), pulmonary edema, headaches, hyperglycemia
Atosiban
MOA
TU
Tox
MOA: oxytocin receptor antagonist
TU: delays labor, rapid onset
Tox: increased fetal mortality
