Uterus Drugs Flashcards
___: goal of labor induction is to stimulate uterine contractions before the spontaneous onset of labor, resulting in vaginal delivery
Oxytocics: goal of labor induction is to stimulate uterine contractions before the spontaneous onset of labor, resulting in vaginal delivery
Drugs used for cervical ripening and purpose?
Dinoprostone, Misoprostol (prostaglandins)
reduces the rate of failed induction, used when induction is indicated but status of cervix is unfavorable
- *Dinoprostone** ( __ analog)
- *Misoprostol** ( __ analog)
- Dinoprostone: PGE2
- vaginal insert, and cervical gel
- Misoprostol: PGE1
- intravaginally, orally or sublingually
- ripens cervix
- stimulates uterine contractions
- these alone initiate labor in many women, and obviates need for oxytocin
Prostaglandins AEs
- Tachysystole
- Fever
- Chills
- Vomiting
- Diarrhea
___ is the preferred drug for inducing labor when the cervix is favorable or ripe
(ripening agent should be used ___ oxytocin in women with unfavorable cervixes)
Oxytocin is the preferred drug for inducing labor when the cervix is favorable or ripe
(ripening agent should be used before oxytocin in women with unfavorable cervixes)
Oxytocin
- elicits milk ejection in lactating women
- 2nd half of pregnancy: uterine smooth muscle becomes increasingly sensitive to stimulant action of endogenous oxytocin
- exogenously given to induce uterine contractions and maintain labor
Oxytocin signaling pathway
GQ → GOAT HAG
GnRH
Oxytocin
ADH (V1-receptor)
TRH
Histamine (H1-receptor)
Angiotensin II
Gastrin
Oxytocin MOA
- Gq - activates voltage-gated Ca2+ channels → myometrial contraction
- also increases prostaglandin synthesis → further stimulating uterine contractions
oxytocin is most commonly given as ___ for labor induction
oxytocin is most commonly given as IV infusion for labor induction
Oxytocin AEs
- Serious toxicity is rare
- excessive stimulation of uterine contractions before delivery can cause fetal distress, placental abruption, or uterine rupture
- High concentrations can activate vasopressin receptors → excessive fluid retention → hyponatremia, HF, seizures, death
____ = MC cause of postpartum hemorrhage
Managed with uterine massage and oxytocic drugs (3)
Uterine atony = MC cause of postpartum hemorrhage
Managed with uterine massage and oxytocic drugs:
- *Oxytocin** (first-line, given IV or IM)
- *Ergot alkaloids**
- *Prostaglandins**
Methylergonovine
- Ergot Alkaloid
- Partial agonist at a-adrenergic receptors and some serotonin receptors
- uterus sensitvity to stimulant effects of ergot alkaloids increase dramatically during pregnancy
Methylergonovine AEs
- HTN
- headache, nausea, vomiting
- chest pains
Methylergonovine contraindications
- Angina pectoris
- Myocardial infarction
- Pregnancy
- Cerebrovascular accident
- Ischemic attack
- Hypertension
Carboprost Tromethamine
PGF2a analog
Given IM
Misoprostol
PGE1 analog
Given vaginally or orally
Tocolytics: given if going into labor < __ weeks of gestation
- Uterine Relaxants
- preterm labor <37 weeks of gestation
- preterm birth = leading cause of neonatal mortality in US
- Management:
- Bed rest
-
Tocolytics
- magnesium sulfate
- indomethacin
- nifedipine
- Glucocorticoids
Glucocorticoids can be given if gestational age is < ___ weeks
Glucocorticoids can be given if gestational age is < 34 weeks
primary purpose of tocolytic therapy is to ____ to allow ____ given to the mother to achieve their maximum effect
primary purpose of tocolytic therapy is to delay delivery to allow glucocorticoids given to the mother to achieve their maximum effect
Glucocorticoids accelerate ____ and decrease risk of neonatal ____, intracranial bleeding, and mortality
Glucocorticoids accelerate maturation of fetal lungs and decrease risk of neonatal respiratory distress syndrome, intracranial bleeding, and mortality
MC tocolytic agents used for treating preterm labor
magnesium sulfate
indomethacin
nifedipine
(Atosiban and B2-agonists as well)
Magnesium Sulfate
- primary tocolytic agent
- uncouples excitation-contraction in myometrial cells through inhibition of cellular action potentials
- AEs
- mother should be monitored for respiratory depression or cardiac arrest
- crosses placenta and may lead to respiratory and motor depression of the neonate
Prostaglandins ___ uterine contractions during normal labor
NSAIDs are used to ___ preterm labor, ___ is the main NSAID for this use
Prostaglandins stimulate uterine contractions during normal labor
NSAIDs are used to delay preterm labor, Indomethacin is the main NSAID for this use
Indomethacin can cause premature closure of ____
effect is mc after ___ weeks of gestation → not recommended to be given after this time
Can also cross placenta and cause ____ d/t decreased fetal renal blood flow if used >48 hrs
Indomethacin can cause premature closure of ductus arteriosus
effect is mc after 32 weeks of gestation → not recommended to be given after this time
Can also cross placenta and cause oligohydraminos d/t decreased fetal renal blood flow if used >48 hrs
