Chapter 8: Drug Therapy During Pregnancy and Breastfeeding Flashcards
drug therapy during preg and breastfeeding
There is a shortage of reliable data regarding toxicity from drug use during pregnancy or breastfeeding
In 2009, the U.S. Food and Drug Administration (FDA) launched the Medication Exposure in Pregnancy Risk Evaluation Program (MEPREP)
preg pt medications
Two thirds of pregnant patients take at least one medication; most take more
For pregnancy-related problems such as nausea, constipation, and preeclampsia
For chronic disorders such as hypertension, diabetes, and epilepsy
For infectious diseases or cancer
Drugs of abuse such as alcohol, cocaine, and heroin
Physiologic changes during pregnancy and their impact on drug disposition and dosing
Third trimester: Renal blood flow is doubled and renal excretion is accelerated
Tone and mobility of bowel decrease
Prolongation of drug effects
placental drug tranfer
All drugs can cross the placenta
Some can cross more easily than others -lipid soluble cross easily
teratogenesis
birth defects:
Gross malformations -Cleft palate, clubfoot, and hydrocephalus
Neurobehavioral and metabolic anomalies
incidence and causes of congenital anomalies
Less than 1% of all birth defects caused by drugs
Identification of teratogens very difficult
Birth defects are rare
Animal tests may not apply to humans
As a result, only a few drugs are considered proven teratogens
Characteristic set of malformations
Act during specific window
Incidence of malformations increase with dose or duration
Minimizing the risk for teratogenesis
Pregnant patients should avoid unnecessary drug use (e.g., alcohol, cocaine)
Responding to teratogen exposure
Identifying details of exposure
Ultrasound scans
teratogenesis and stage of development
Development occurs in three stages:
Conception through week 2
Embryonic period: Weeks 3 through 8 -Gross malformations produced by teratogens
Fetal period: Week 9 through delivery -Functions disrupted with teratogen exposure
Not every exposure = birth defect.
May have delayed effect: diethyl stilbrdterol -> vaginal cancer in the offspring that develops years later
FDA Pregnancy RF
A: Safest, remote risk for fetal harm. No evidence of harm in the trimesters
B: More dangerous than A, Animal studies showed some risk, no studies in women or animals stuies do show a risk for fetal harm, bt controlledstudies in women have failured to demo a risk during first trimester or no evidence of risk for later trimesters
C: More dangerous than A and B, Animal studies showed risk, no studies in women Or maybe no studies in either
D: More dangerous than A, B, and C, Proven risk of fetal harm, Studies in women showed proof of fetal harm but the benefit of the medication may outweigh the risk to the developing fetus (ex. tx of life-threatening diseae fo which safer drugs are ineffective). statement appears in waring section of drug label.
X: Most dangerous; known to cause fetal harm, Proven risk for fetal harm , + in animals and women, Very definite results . or ADR reports evidence of fetal risk. risk outweighs benefit. statement appears in he contraindication section of drug labels.
created in 1979, Obsolete in 2020
FDA came out with preg and lactation labeling rule
Drugs that were in use before 1983 are not required to be classified with preg RF
drug therapy during BF
Drugs can be excreted in breast milk, and effects can occur in the infant
ex. anti-cancer and immunosuppressants
how to decrease risk to the infant
Take drugs immediately after breastfeeding
Avoid drugs that have long half-lives
Choose drugs that tend to be excluded from milk and that are least likely to affect the infant
Avoid drugs that are known to be hazardous
anticancer/immunosuprpressant drugs and their teratogenic effects
cyclophsphamide: CNS malformation, seconardy cancer
methotrexate: CNS and limb malformations
thalidomide: shortened limbs, internal organ defects
antiseizure drugs and their teratogenic effects
carbmazepine: NTD, craniofacial defects, malformation of heart, and hypospadias
phenytoin: growth delay, CNS defects
topiramate: growth delay, cleft lip with chelf palate
valporic acid: NTD, cranialfacial defects, malfomation of heart and extrimities, hypospadias
sex hormones and their teratogenic effects
androgens (danazl): masculinization of the femsld fetus
diethylstilbestrol: vaginal carcinoma in female offspring
estogens: congenital defects of female reproductive organs
antimicrobial drugs
tetracycline: tooth and bone abnormalities
tri-sulf: NTD, CV malformations, celft palate, culbfoot, and rinary tract abnormalities
alc teratogenic effects
FAS, still birth, spon abortion, low birth weight, intelluctual abilities,
5-a-reductase inhibitors (dutasteride, findsteride) eratogenic effets
maformation of external geneitals in men
