Perinatal Pharmacology Flashcards
(16 cards)
How do drugs cross the placenta?
Via maternal spiral arteries into the intervillous space, syncytiotrophoblast, fetal capillaries
This process is influenced by factors such as drug size, lipophilicity, ionization, and protein binding.
What factors influence placental drug transfer?
Drug size, lipophilicity, ionization, protein binding
Additionally, placental enzyme metabolism (CYP450) and transport mechanisms (active vs passive) are also influential.
What maternal physiological changes affect drug concentration during pregnancy?
Increased plasma volume, total body water, cardiac output; decreased drug concentration
These changes enhance placental perfusion and affect renal clearance.
What happens to drug clearance during pregnancy?
Increased renal clearance due to increased GFR and renal blood flow
This is also accompanied by decreased albumin leading to increased free drug fraction.
What are teratogens?
Substances that cause birth defects
Examples include thalidomide and alcohol.
What is the Pregnancy and Lactation Labeling Rule (PLLR)?
Replaced old FDA A/B/C/D/X categories for drug risk classification during pregnancy
This system provides more detailed information about the risks of medications.
What are some medications related to preterm birth?
Tocolytics: Nifedipine, Indomethacin, Terbutaline, Magnesium sulfate
Corticosteroids like betamethasone or dexamethasone are also used.
What defines chronic hypertension during pregnancy?
Present before 20 weeks gestation or persists more than 12 weeks postpartum
This condition is distinct from gestational hypertension and preeclampsia.
What is gestational hypertension?
Diagnosed after 20 weeks gestation
It is characterized by elevated blood pressure without proteinuria.
What characterizes preeclampsia?
Hypertension with proteinuria or end-organ damage
Severe features include blood pressure greater than 160/110 and signs of end-organ dysfunction.
What medications are used to manage hypertension in pregnancy?
Labetalol, nifedipine ER, methyldopa
For hypertensive emergencies, IV labetalol, hydralazine, or oral nifedipine IR may be used.
What is the purpose of magnesium sulfate in pregnancy?
Seizure prophylaxis
It is particularly used in cases of severe preeclampsia.
When should GBS screening occur during pregnancy?
At 36 weeks gestation
Treatment is necessary for unknown or positive cases.
What antibiotics are used for GBS prophylaxis?
Penicillin G, Ampicillin, Cefazolin
Alternatives include limited use of Clindamycin and Vancomycin.
What are the uses of misoprostol in obstetrics?
Labor induction, cervical ripening, miscarriage management, postpartum hemorrhage
It can be administered via vaginal, oral, buccal, or rectal routes.
What are the risks associated with misoprostol?
Hypertonia, fetal distress; boxed warnings apply
Caution is necessary due to potential severe side effects.
