OB Pharmacology Flashcards
3 Ways Products of Conception are Evacuated
Surgical
medical
Expectant
Reasons for Surgical Removal of Product of Conception
Unstable
Significant bleeding
Infection
Want immediate treatment
Reason for Medical Removal of Products of Conception
Do not want to wait for spontaneous passage
Define Expectant Evacuation of Products of Conception
Will eventually pass naturally
Days to weeks
Main Drug for Medical Management of Spontaneous Abortion
Misoprostol
Uses of Misoprostol
Missed abortion
Incomplete abortion
Cervical ripening (unlabeled use)
Postpartum hemorrhage (unlabeled use)
What is misoprostol?
Prostaglandin E1 analog
Induces uterine contractions
Route of Misoprostol Administration
Vaginally
Every 4 hours x 4
Medication Classes for Preterm Labor
Tocolytics
Corticosteroids
Goals of Tocolytics
Delay delivery by at least 48 hours
Provide transport time for mother
Stop labor to clear underlying medical condition
Benefits need to Outweigh Risks for Administration of Tocolytics
NOT for >34 weeks
Controversial
Contraindications for Tocolytics
Baby or mother unstable Fetal demise Lethal fetal anomaly Non-reassuring fetal status Severe pre-eclampsia or eclampsia Maternal hemorrhage Intra-amniotic infection Maternal contraindication to drug
Drug of Choice for 24-32 Weeks of Gestation (Preterm Labor)
Indomethacin
MOA of Indomethacin
Decreases prostaglandin production through inhibition of cyclooxygenase
Administration of Indomethacin
PO
PR
Maternal SE of Indomethacin
Nausea GE reflux Gastritis Emesis Platelet dysfunction
Fetal SE of Indomethacin
Constriction of ductus arterioles
Oligohydramnios
Neonatal complications
When does indomethacin constrict the ductus arteriosus?
If given for >48 hours
Give past 32 weeks
Why oligohydramnios with use of indomethacin?
Decreases fetal urine output
Decreasing amniotic fluid volume
Neonatal Complications with Indomethacin Use
Bronchopulmonary dysplasia Necrotizing enterocolitis PDA Periventricular leukomalacia Intraventricular hemorrhage
Maternal Contraindications of Indomethacin
Platelet dysfunction Bleeding disorders Hepatic dysfunction GI ulcers Renal dysfunction Asthma if sensitive to ASA
Second Line Therapy of Tocolytics
Nifedipine
MOA of Nifedipine
Myometrial relaxation
Peripheral vasodilation
Maternal SE of Nifedipine
Nausea Flushing Headache Dizziness Palpitations Can cause severe hypotension
Contraindications of Nifedipine
Hypotension
Preload dependent cardiac lesion
Cautious with LV dysfunction or CHF
Precaution with Nifedipine
Do not use with magnesium sulfate
Act synergistically & result in respiratory depression
Pharmacokinetics of Nifedipine
Half life: 2-3 hours
Peak plasma concentrations: 30-60 minutes
Metabolized: liver
Excreted: kidney
Drug of Choice for 32-34 Weeks Gestation (Preterm Labor)
Nifedipine
2nd Line Therapy for 32-34 Weeks Gestation (Preterm Labor)
Beta-adrenergic receptor agonists
Terbutaline
Maternal SE of Terbutaline
Tachycardia Palpitations Hypotension Tremor SOB Chest discomfort Hypokalemia Hyperglycemia
Contraindications of Beta Adrenergic Receptor Agonists
Tachycardia sensitive cardiac disease
Uncontrolled hyperthyroidism or DM
Caution in placenta previa or abruption due to hypovolemia & shock
Administration Routes of Terbutaline
SubQ
IV
Monitoring with Terbutaline
I/Os
Maternal symptoms: SOB, CP, tachycardia
Stop drug if maternal HR >120
Blood glucose & K+ every 4-6 hours
Why do we need to check potassium with terbutaline?
Potassium moves intra-cellularly
3rd Line Therapy for Prevention of Preterm labor
Magnesium sulfate
Corticosteroids Reduces Incidence of What in the Neonate?
Respiratory distress syndrome Intraventricular hemorrhage Necrotizing enterocolitis Sepsis Neonatal mortality
Antenatal Corticosteroids
Betamethasone**
Dexamethasone
When can you give mom antenatal corticosteroids to help lung development of the fetus?
23-34 weeks
Indications for Antibiotic Prophylaxis for Group B Strep
Positive rectovaginal culture
Positive history of birth of an infant with early onset GBS disease
GBS bacteriuria during current pregnancy
Unknown culture status AND maternal fever >100.4 OR preterm labor 18 hours)
Antibiotic Regimen for Group B Strep
Penicillin G or Ampicillin
PCN Allergy: cephazolin (Ancef), clindamycin, or vancomycin
Antibiotic Prophylaxis of Premature Rupture of Membranes
Azithromycin on admission
+ ampicillin x 48 hours
+ amoxicillin x 5 days
PCN allergy: clindamycin x48 hours + gentamicin x48 hours + clindamycin x5 days
Additional Medical Therapy for Premature Rupture of Membranes
Tocolytics: delay delivery
Corticosteroids as indicated
Medications for Postpartum Hemorrhage
Oxytocin
Misoprostol
Carboprost tromethamine
Methylergonovine maleate
Oxytocin Routes of Administration
IV
IM
Response time of IV Oxytocin
1 minute