Drugs Acting on the Uterus Flashcards
what pharmacological intervention is used for cervical ripening
Misoprostol (PGE-1)
Dinoprostone (PGE-2)
Misoprostol is not FDA approved for obstetrics. What is it FDA approved for?
reducing risk of NSAID induced gastric ulcer
AE of prostaglandins
Tachysystole Fever Chills Vomiting Diarrhea
what drug is most common used for inducing labor? What must be ready before use of the drug
Oxytocin - labor induction
Cervix must be ripened/favorable; If not, cervix ripening drug must be given before oxytocin
mechanism of oxytocin
- binds to its receptor and couples with Gq –> activates phospholipase C (PLC) –> hydrolyzes PIP2 to IP3 and DAG –> IP3 release Ca from SR while DAG activates Phophokinase C (PKC) –> Ca activates MLCK –> myometrial contraction
- activating oxytocin receptor –> activation of MAPK and cPLA2 –> prostaglandin synthesis –> uterine contracton
AE of oxytocin
- excess stimulation of uterine contraction –> fetal distress, placental disruption, uterine rupture
- activate vasopressin receptor –> excessive fluid retention or water intoxication –> hyponatremia –> heart failure, seizure, death
what is most common cause of post partum hemorrhage and how is it treated
uterine atony (loss of tone in uterine musculature)
Tx: COMM Carboprost Tromethamine (prostaglandin) Oxytocin (first line) Methylergonovine (ergot alkaloid) Misoprostol (prostaglandin)
mechanism of methylergonovine
partial alpha receptor agonist and serotonin receptor agonist
acts on SM of uterus to increase the tone, rate, and amplitude of rhythmic contraction
contraindication of methylergonovine
- Angina Pectoris
- MI
- Pregnancy
- Cerebrovascular Accident
- TIA
- Hypertension
caution if breast feeding because methylergonovine can be found in breast milk and can lead to ergot poisoning and gangrene in nursing infant
how is pre term labor managed
Bed rest
Tocolytics
Glucocorticoids
why are tocolytic given in women about to give birth to a preterm baby
to delay delivery for 48 hours to allow glucocorticoids given to mother to achieve their maximal effect –> mature fetal lungs so as to prevent respiratory distress syndrome
what are the tocolytics
MINAT
Magnesium Sulfate Indomethacin Nifedipine Atosiban Terbutaline
Contraindications of tocolytics
M-FACE
Maternal Hemodynamic instability
Fetal demise and Fetal Maturity
Acute fetal distress
Chorioamnionitis
Eclampsia or Severe Pre eclampsia
mechanism of magnesium sulfate
uncouples excitation-contraction in myometrial cells through inhibition of cellular action potentials
contraindicated in myasthenia gravis and renal failure
AE for magnesium sulfate/what should the mother be monitored for
Mother should be monitored for respiratory depression or cardiac arrest
could also cross placenta and lead to respiratory and motor depression in neonate
