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OBSTETRICAL DRUG REVIEW
Teratogens
 Definition: A drug, agent, or influence that
adversely affects fetal growth, development,
or health
Benefit-to-Risk Ratio
 Estimates if the benefit of the medication to
the fetus is greater than the known or
unknown risk of side effects of the drug on
mother and baby
Distribution
 Not all drugs in breast milk are well absorbed
by the neonate
 Breastfeeding baby ingests only 1-2% of
mother’s total dose
 Most narcotics such as morphine and
demerol are not harmful to infants of
C-section breastfeeding mothers
 However, tobacco and alcohol should be
avoided as these substances enter breast
milk in large doses
Prostaglandins
Prostaglandin Gel (Cervidil or Prepidil)
-used to “ripen” or soften the cervix prior to induction of
labor. May also stimulate uterine contractions
Prostin 15M/Carboprost (Hemabate)
-used for postpartum hemorrhage. Dose is 250 mcg IM or
intramyometrically (directly into the musculature of the
uterus)
Misoprostol (Cytotec)
-used to treat postpartum hemorrhage. Dose is 800 or
1,000 mcg per rectum
Oxytocics: Uterine Stimulants
Pitocin (Oxytocin)
 Uses
 Before Birth: For induction and augmentation of labor
 After Birth: Used to prevent postpartum hemorrhage
 Administered by IV; IM in emergencies
 Induction: Infuse slowly via pump @ 0.5 mU/min; increase rate
every 20-30 minutes until contraction pattern established. Close
monitoring of fetal and uterine status is necessary
 Postpartum: After placental expulsion, mix 20 units in 1,000 mL
LR. Bolus immediately after birth then run at 125 mL/hr
 Side effects: Hypertension; water intoxication (due to anti-
diuretic effect); hyponatremia
Oxytocics: Uterine Stimulants
Methergine (Methylergonovine)
 Oxytocic; induces uterine contractions
 Routinely used for postpartum hemorrhage or
postpartum uterine atony
 0.2 mg given IM or PO
 Side effect: Hypertension (therefore not
given to patients with preeclampsia)
Tocolytics: Contraction Inhibitor
Terbutaline (Brethine)
 Inhibits contractions by affecting smooth
muscle action
 Used after 20 weeks gestation and up until
34-35 weeks gestation to stop preterm
labor/contractions
 0.25 mg SQ; usually repeated in 20 minutes.
Up to 3 doses if necessary. No oral
terbutaline r/t adverse side effects
 Common side effect is tachycardia. Hold if
HR is > 120 bpm!
Tocolytics: Contraction Inhibitor
Magnesium Sulfate (MgSO4)
 Competes with calcium entry into muscle,
thus reducing contraction intensity
 Used to stop preterm labor
 Therapeutic range 4-7 mEq/L
 Administered IV; always on a pump
 Toxic level may occur if renal functioning is
poor
Tocolytics: Contraction Inhibitor
Indomethacin (Indocin)
 Non-steroidal, anti-inflammatory used to control
preterm labor. Also reduces amniotic fluid in
patients with polyhydramnios. Also aids in
closing patent ductus arteriosis (PDA) in
newborns
 Anti-prostaglandin; decreases effect of
prostaglandin, thus relaxing smooth muscle
 Has slight anti-coagulant effect so not given to
women with bleeding potential or peptic ulcers
Corticosteroid
Betamethasone (Celestone)
 Long-acting corticosteroid
 Stimulates maturity of fetal lungs and production
of surfactant between 28 and 34 weeks to lessen
chance of respiratory distress syndrome
 12 mg given IM every 24 hours X 2 doses
 For maximum benefit, the delivery should be
delayed for at least 48 hours after administration
Drugs Used in Pre-eclampsia
Magnesium Sulfate (MgSO4)
 Depresses neuromuscular transmission
 CNS depressant; depresses CNS activity and
decreases CNS irritability
 Prevents seizure or eclampsia
 Toxic levels can cause respiratory arrest;
death
 Dose: Bolus 4-6 grams/hr; maintenance dose
1-2 grams/hr
 Critical drip therefore always on a pump!
Narcotic Antidote
Naxolone (Narcan)
 Used to reverse the effects of opioids
including respiratory depression, sedation,
and hypertension
 Causes severe withdrawal in substance
abusers
 Do not administer to the newborn of a drug
abuser or patients on methadone
Anesthetics or Locals
 Spinals
 Epidurals
 Regional Blocks
 Generals
 Marcaine
 Xylocaine (Lidocaine)
Neonatal Drugs
 Erythromycin Ophthalmic Ointment

Prevents gonorrhea and chlamydia eye infections in the newborn.
Parents can refuse
 Vitamin K

Aids with clotting. Parents can refuse
 Hepatitis B Vaccine (Heptavax)



3-shot series. First dose at birth; second dose a month later
followed by last shot at 6 months of age
Requires a signed consent!
Why? Some parents believe the vaccine will cause autism.
Extensive research confirms no relationship