Pharmacology During Pregnancy Flashcards
(21 cards)
How does lipid solubility of drugs influence pregnancy?
- lipophilic drugs cross placenta faster and cross BBB easier
- highly ionized drugs cross more slowly
What are the drugs used for Cesarean section?
- Bupivacaine (spinal anesthesia)
- Midazolam (pre-spinal anesthesia)
- Fentanyl/Remifentanil (analgesia)
- acetaminophen/NSAIDs (post-op pain)
What is a positive of using Remifentanil during a C-section?
has a low risk for crossing placenta
What is the correlation between MW and placenta crossing of drugs?
- MW of 250-500 can easily cross
- MW of 500-1000 cross with difficulty
- MW greater than 1000 cross poorly
why is Heparin preferred over Warfarin?
- heparin has greater MW and more polarized —> less cross ability –> preferred
- warfarin is teratogenic and has hemorrhagic effect
What is the effect of protein binding and placenta crossing?
- degree to which a drug is bound to plasma proteins (particularly albumin) may also affect the rate of transfer and the amount transferred
- higher affinity = slower transfer rate = slower to cross placenta
How does lipid solubility affect protein binding?
highly lipid soluble compounds will not be greatly affected by protein binding
What role does the placenta play in fetal drug metabolism?
- it is a site of metabolism for some drugs
- drugs that cross the placenta enter via the umbilical vein —> enters fetal liver (40-60%)
***slower than maternal
What are the categories for FDA Teratogenic risks of drug exposure?
A: not shown to have increased fetal risk of abnormalities
B: no adequate or well controlled studies OR animal studies shown adverse effects BUT failed to show risks in fetus of in pregnant women
C: no studies or animal studies show risk
D: risk to fetus but benefits may outweigh potential risk
X: risk to fetus –> use contradicted
What do toxic drug actions depend on in pregnant women?
- stage of development
What are examples of toxic drug actions?
- Thalidomide can cause Phocomelia
- fetal alcohol syndrome
- child is thinner with less body fat –> nicotine/cocaine can cause
vasoconstriction —> less blood flow –> less development
What are the fetal therapeutics used during pregnancy and what are they used for?
- Corticosteroids –> stimulate fetal lung development (also for pre-mature newborns)
- Phenobarbital –> induce fetal hepatic enzymes
- Digoxin, Flecainide, Verapaml –> fetal cardiac arrhythmias
- Antivirals –> decrease/eliminate transmission to fetus
What must be considered when taking drugs during breastfeeding?
- most drugs are detectable in breast milk
- breast milk has lower pH (6.8) than plasma (7.4) –> weak bases can accumulate in milk
- weak acids can cause major effects on newborns but do not accumulate as easily in BM
When should a nursing mother take medication?
- 30-60 min after nursing and 3-4 hours before the next feed
What is the correlation of antibiotics and breastmilk and what are examples of contradicted antibiotics?
- most antibiotics are detected in BM
- tetracyclines –> high concentrations (70% mothers serum)
- Isoniazid –> reaches equilibrium fast —> pyridoxine deficiency (B12)
what are the effects of CNS depressants in breastmilk?
sedatives/hypnotics can sedate the nursing infant
What are examples and the adverse effects of CNS depressants on nursing infants?
- barbs: lethargy, sedation, poor suckle reflex
- diazepam: sedation
- opioids: neonatal dependance
- ethanol: excessive amounts cause sedation
what are the effects of stimulants in breastmilk?
- nicotine is found in low amounts –> minimal effects
- caffeine –> small amounts
what are the effects of Chloramphenicol on lactation?
bone marrow sepression (DO NOT USE)
what are the effects of oral contraceptives on lactation?
may suppress lactation in high doses
what are the effects of Propylthiouracil on lactation?
may suppress thyroid function
