Pharmacology Flashcards
How does administration of a drug change in pregnancy?
delayed gastric emptying, nausea and vomiting, decreased esophageal sphincter tone
How does dispersion of a drug change in pregnancy?
increase volume distribution (increase TBW, ECF, fat)
decrease serum protein
How does metabolism of drugs change in pregnancy?
decrease in CYP 1A2 and 2C19 activity
increase in CYP 3A4, 2D6, 2C9, UGT activity
How does elimination of a drug change during pregnancy?
GFR increases by 50% (increased CO and renal blood flow)
What type of medications are likely to cross the placenta?
lipophilic
unionized; weak bases
low MW < 600 Da
not highly protein bound
When in pregnancy is the fetus most sensitive to teratogens?
first 8 weeks
If a drug is pregnancy category A, what does this mean?
studies in pregnant women show no risk to fetus
If a drug is pregnancy category X, what does this mean?
risk of using in pregnant women outweighs the possible benefit
Medications to avoid in pregnancy
carbamazepine, VPA, lithium, phenytoin, barbituates, opiods/benzodiazepines, statins, ACEi/ARBs/allskiren, warfarin, NSAID, tetracycline, Isotretinoin, chemotherapy, methotrexate, misoprostol, thalidomide
Women taking ___ at time of fertilization are less likely to develop serious nausea and vomiting
multivitamin
Nausea and vomiting usually begins around ____ and usually resolves around
4-6 weeks
16-20 weeks
first line for treating nausea and vomiting in pregnancy
B6, switching prenatal vitamin to folic acid, nausea bands, unisom
what causes GERD in pregnancy?
increase in progesterone resulting in relaxation of LES
First line management for GERD in pregnancy
lifestyle modifications
If lifestyle modifications are not effective in female patient with GERD, what medications do you want to try?
antacids (Mg, Ca) → H2 blockers (ranitidine) → PPI (omeprazole)
GERD drugs to avoid in pregnancy
sodium bicarbonate, magnesium trisilicate
first line for managing constipation in pregnancy
moderate physical activity, increase dietary fiber and fluid intake
Why do pregnant women experience constipation?
uterus compresses colon and increase in progesterone levels
second line for managing constipation in pregnancy
bulk forming laxatives (psyllium) or stool softener (docusate)
Third line for constipation in pregnancy
non saline osmotic laxative (PEG)
Fourth line for constipation in pregnancy
short term use of stimulant laxatives (bisocodyl, senna)
Constipation medcations to avoid in pregnancy
magnesium citrate, sodium phosphate, castor oil, mineral oil
Why do pregnant women get hemorrhoids?
increased abdominal pressure by large uterus → vascular engorgement and venous stasis
Medications for hemorrhoids a pregnant woman should avoid
NSAID
First line for treating hemorrhoids in pregnancy
increase dietary fiber and fluid intake
second and third line treatments for hemorrhoids in pregnancy
stool softeners, sitz baths
topical anesthetic, skin protectant and astringent
4th and last line for hemorrhoids in pregnancy
hydrocortisone suppositories
surgery
what percent of women have improvements in migraines in pregnancy?
60-70%
What can you use for headaches during pregnancy?
acetaminophen
Use to treat migraine headaches in pregnancy
sumatriptan
why do pregnant women experience allergic rhinitis?
nasal congestion due to vascular engorgement of nasal passages and hormonal effects on mucus secretion
what drugs can you use to treat allergic rhinitis in pregnancy?
intranasal steroid (intranasal cromolyn) → oral antihistamine → intranasal decongestant (oxymetazoline)
Drugs for allergies to avoid in pregnancy
oral decongestants, initiating or altering immunotherapy, systemic budesonide and triamicinolone, fexofenadine
women who are not diagnosed with diabetes should undergo screening with OGTT @
24-28 weeks
first line therapy for gestational diabetes
insulin
2nd and 3rd line drug therapy for gestational diabetes
metformin
glyburide
what do you use to treat hypothyroidism in pregnant patient?
levothyroxine (may need to increase dose)
Drugs used to treat hyperthyroidism in pregnancy
propylthiouracil → 1st trimester
methimazole → 2nd and 3rd trimesters
Thyroid medication to avoid in pregnancy
iodine 131
4 categories of hypertension in pregnancy
preeclampsia-eclampsia
chronic
chronic with superimposed preeclampsia
gestational
Goal BP in pregnancy
120-160/80-105
Pharmacotherapy safe for hypertension in pregnancy
labetolol
nifedipine
methyldopa
hypertension meds to avoid in pregnancy
ACE inhibitors, ARBs, renin inhibitors, mineralocorticoid receptor antagonists
anticoagulation therapy safe in pregnancy
LMWH or UFH
anticoagulation therapy to avoid in pregnancy
warfarin, DOAC, fondaparinus, lepirudin, bivalirudin
Drugs approved for UTI in pregnancy
penicillins and cephalosporins
antibiotics to avoid for UTI in pregnancy
sulfa drugs (3rd trimester), trimethoprim (1st trimester), fluoroquinolones, tetracycline Nitrofurantoin (caution in 1st trimester & last month)
Definition of preterm labor
cervical dilation or effacement with regular uterine contractions between 20 and 37 weeks gestation
administered to preterm baby to promote maturation of fetal lungs and other organ systems
antenatal corticosteroids → betamethasone or dexamethasone
Who should receive antenatal steroids in pregnancy?
women 24-34 weeks gestation at risk for delivery within 7 days
administered to preterm baby to provide fetal neuroprotection (reduces risk for cerebral palsy)
magnesium
drug used to prolong delivery
tocolytic
why would you administer a tocolytic in preterm labor?
allow for administration of antenatal steroids or magnesium
transportion of mother to another facility
ADE of nifedipine (CCB) in preterm labor
hypotension or reduction in uroplacental blood flow
ADE of prostaglandin inhibitors (NSAID) in preterm labor
increased risk of premature closure of PDA if used > 32 weeks for > 48 hours
ADE of B-adrenergic receptor agonists in preterm labor
tachycardia, arrhythmia, hyperkalemia, hyperglycemia, hypotension, pulmonary edema
ADE of magnesium sulfate in preterm labor
rare (unless at toxic levels) tetany, cardiac arrest, respiratory depression
indications for labor induction
post term pregnancy, maternal medical conditions (DM, renal disease, COPD, HTN, pre-eclampsia, infections), fetal compromise or demise
Drugs that cause cervical ripening/labor induction
misoprostol and dinoprostone
this drug is synthetic PGE1 analogue that is administered intravaginally that causes cervical ripening
misoprostol
This drug is PGE2 vaginal gel or insert that causes cervical ripening
dinoprostone
This drug induces labor by stimulating uterine contractions
oxytocin (pitocin)
nonpharmacological ways to induce labor
mechanical cervical dilator, membrane stripping, amniotomy, nipple stimulation
medications to avoid in breastfeeding
amphetamines, cocaine, chemo, lithium, benzo, ergotamine, nicotine
medications that can decrease milk produciton in breast feeding women
alcohol, dopamine agonists, estrogen, testosterone, pseudophedrine, high dose steroids, strong antihistamines
medications that can increase milk production (galactagogues)
metoclopramide and fenugreek
medicaitons likely to be excreted in breast milk
lipophilic, unionized; weak bases, low MW, not highly bound, high maternal plasma concentration