Pharm - Pregnancy Flashcards
What are the three timeframes that impact the likelihood of teratogenic effect
- Pre-embryonic period (0-14 days)
- Embryonic period (14-56 days)
- Fetal period (57 days to delivery)
What is impact of teratogen exposure during pre-embryonic period
exposure usually all or none effect; either dies or is damaged and then regenerates completely (sub-lethal exposure)
What is impact of teratogen exposure during embryonic period
organogenesis takes place, embryo must susceptible to teratogens; major structural changes or damage can occur
What is impact of teratogen exposure during fetal period
histogenesis and functional maturation, minor structural changes can occur but most anomalies are more likely to involve growth and functional aspects such as development of the brain and reproductive organs
Do most meds cross the placenta?
yes
List the 11 teratogenic drugs we need to know AND their FDA class
- ACE Inhibitors and ARBS: D
- Methimazole: D
- Atenolol: D
- Carbamezepine: D
- Methotrexate: X
- Paroxetine: D
- Phenytoin: D
- Systemic retinoids: X
- Tetracycline: D
- Valproic Acid: D
- Warfarin: X
Why is iron important during pregnancy
Required to expand maternal red cell mass and for the fetus and placenta
What two pregnancy related supplements are based on the elemental content?
iron
calcium
Which form of iron supplement is most common, why?
- ferrous sulfate (20% elemental iron)
- least expensive and MC used form of iron
What is supplementation recommendation for
- a non anemic woman?
- a woman with iron deficient anemia or risk of iron deficiency
- 15-30 mg/day
- 60-120 mg/day
RF for iron deficiency during pregnancy
- multiple gestation
- closely spaced pregnancies
- diet low in red meat and ascorbic acid
- chronic aspirin/NSAID use
- donate blood > 3/year
Why is folic acid important during pregnancy?
plays role in neural tube closure (by 6 weeks gestation)
Folic acid recommendations
- normal pregnancy
- high risk
- 0.4 mg/day
- 4 mg/day (starting 1 month prior to conception and at least 3 months into pregnancy)
How to supplement 4 mg of folic acid
- Can’t just take extra prenatal pills, will risk toxicity of other vitamins.
- Must use a folic acid supplement
Calcium recommended supplementation during pregnancy
- ≥19 yo: 1,000 mg/D
* <19 yo: 1,300 mg/D
What is most commonly type of calcium supplement used
calcium carbonate - higher amt of elemental calcium
Treatment of mild n/v during pregnancy
- Reassurance, lifestyle changes or medication. Want to avoid dehydration, hypokalemia, metabolic alkalosis
- Frequent small meals, avoid strong smells. Bland fods higher in carbs and lower in fats usually better tolerated (French baguette and white potatoes!!)
First line therapies for n/v in pregnancy if lifestyle isn’t working
- Vitamin B6 (pyridoxine)
- Add doxylamine if not well controlled on pyridoxine alone
- Combo product: Diclegis: pyridoxine/doxylamine delayed release. Scheduled doses, not PRN
- Ginger (helps with nausea, not vomiting)
Second line therapies for n/v in pregnancy
- DC pyridoxine and doxylamine
- Start antihistamines (H1 antagonists)
• Meclizine (also for vertigo)
• Dimenhydrinate or diphenhydramine (drowsiness)
Third line therapies for n/v in pregnancy
- Dopamine receptor antagonist if antihistamines are inadequate
• Phenothiazine: Prochlorperazine
• Benzamide: Metoclopramide (Reglan) - ADR: sedation
Fourth line therapies for n/v in pregnancy
- 5-HT3 serotonin receptor antagonists
• Ondansetron (Zofran)
• Small risk of congenital anomalies – use with caution.
• Can cause QT prolongation, esp with arrhythmia RF
Hyperemesis gravidarum
- risk
Dehydration and malnutrition
Hyperemesis gravidarum
- tx
- hospitalization
- IV fluid
- electrolytes
- antiemetics
- sedation
- parenteral nutrition support
First line treatment for constipation in pregnancy
Nonpharm:
- increase exercise
- fluids
- fiber (cereals, fruits, vegetables, beans, wheat bran)
Second line treatment for constipation in pregnancy
laxatives
List the laxatives used in pregnancy in order of preference
- Bulk-producing
- Osmotic
- Stimulant
*most not absorbed out of gut so considered safe with ST use
Bulk-producing laxatives used in pregnancy
- Psyllium, calcium polycarbophil, methylcellulose
- Dilute in water and take before meal or at bedtime
- Increase fecal water content/volume, decrease colonic transit time, improve stool consistency
Osmotic laxatives
- only use short term or occasionally
- Polyethylene glycol (Miralax) is best option for chronic constipation
- Lactulose or sorbitol other options
Stimulant laxatives
- Use if fail to respond to bulk or osmotic laxatives
- MoA: affects fluid changes in large intestine and/or GI motility, can result in diarrhea → dehydration and electrolyte disturbances
- 2-3 X week is safe and effective for most patients
List the three stimulant laxatives used in pregnancy
- senna (best option)
- bisacodyl
- cascara
List 4 laxatives to avoid in pregnancy
- Castor oil
- Saline osmotic laxatives (magnesium and phosphosoda)
- Mineral oil
- Aloe
use of stool softeners in pregnancy
- questionable efficacy, marginal value
- low risk
GERD in pregnancy - tx of mild sx
• Lifestyle changes and diet modifications
- Elevate head of bed 6”
- Avoid eating late at night/close to bedtime
- Avoid salicylates, caffeine, alcohol (duh!), nicotine, and foods that cause reflux
GERD - first line threapy
Antacids
- calcium containing are best option
- don’t take with iron, need normal gastric pH to absorb iron
What antacids should be avoided during pregnancy
- magnesium containing antacids late in pregnancy d/t tocolytic properties
- magnesium trisilicate
- sodium bicarbonate (Na+ overload, alkalosis and fluid overload)
What is alternative to antacids for GERD in pregnancy
sucralfate - binds to erosions, stays local
What is next step if antacids/sucralfate dont’ control GERD
use systemic meds. Avoid during 1st trimester if possible
List the systemic meds used to treat GERD in pregnancy in order of preference
- H2-receptor antagonists
- Promotility drugs
- PPI
What H2-receptor antagonists are used to great GERD in pregnancy
- Ranitidine first (documented safety - Famotidine (limited data but appears safe)
What H2-receptor antagonists should be avoided in the tx of GERD in pregnancy
nizatidine (axid)
What promotility drug should be used to treat GERD in pregnancy
Metoclopramide - increases lower esophageal sphincter tone
What PPIs can be used in pregnancy
- Limited data on safety in pregnancy
- Avoid during first trimester
- Lansoprazole and pantoprazole Class B
- Omeprazole class C
What are 4 conservative treatment of hemorrhoids in pregnancy
- Fiber supplements
- Fluids
- High fiber diet
- Switch iron supplements to slow release formulation
What ingredients are skin protectants used in meds to treat hemorrhoids
- aluminum hydroxide
- cocoa butter
- glycerine
- kaolin
- lanolin
- mineral oil
- petrolatum
- zinc oxide
- calamine
What ingredients are topical anesthetics used in meds to treat hemorrhoids
-caines and pramoxine
What ingredient is an astringent used in meds to treat hemorrhoids
witch hazel
What ingredient is an anti-inflammatory used in meds to treat hemorrhoids
hydrocortisone
What products should be avoided to treat hemorrhoids in pregnancy
products containing local vasoconstrictors (epinephrine or phenylephrine)
What is the role of methyldopa in the treatment of HTN in pregnancy
- Widely used for many years but rarely used anymore
* Con: slow onset of action, most women don’t reach bp goals
What is the best beta blocker to use to treat HTN in pregnancy
Labetalol
• Both alpha and beta adrenergic blocker
• May preserve uteroplacental blood flow better than traditional BB
• Faster onset than methyldopa
• Generally safe in pregnancy, associated with hepatotoxicity
• Avoid other BB due to adverse effects on fetus
What is the CCB recommended for use to treat HTN in pregnancy
Nifedipine
- use the sustained release, not the regular release
What four classes of drugs should NOT be used to treat HTN in pregnancy
- ACE inhibitors
- ARBs
- direct renin inhibitors
- mineralocorticoid receptor antagonists
What is the goal of glucocorticoid use in pregnancy? What two meds are used?
- Reduce the incidence and severity of respiratory distress syndrome in the infant
- Betamethasone and dexamethasone
What are two antihypertensive drugs of choice for the acute treatment of severe hypertension
- IV Hydralazine (drug of choice)
* IV Labetalol
What is magnesium sulfate used for in pregnancy?
- prevention and treatment of eclamptic seizures (also as a tocolytic)
Loading and maintenance dose of mag sulfate
- Loading dose: 4-6 g IV
* Maintenance dose: continuous infusion 2 g/hour (via controlled pump to avoid accidental OD)
What are three monitoring parameters for toxicity of mag sulfate, at what drug level will toxicity occur
• Deep tendon reflex (first sign usually)
- 8-12 mg/dL
• Respiratory rate (arrest is risk)
- >13 mg/dL
• Urine output
What organ function is necessary for the use of magnesium sulfate
renal function
What is used to reverse magnesium sulfate toxicity?
calcium gluconate
- Can reverse hypocalemia and hypocalcemic tetany d/t elevated magnesium levels
First line therapy for GDM
diet and lifestyle (move)
Glycemic goals for GDM
- <140 mg/dL 1 hour post-prandial
* <120 mg/dL 2 hours post-prandial
What is the preferred drug to treat GDM
insulin
How to start insulin therapy for GDM
• Start with postprandial rapid or fast acting
- Humalog and Novolog have been investigated in pregnancy
- Regular is ok too
- Analogs preferred over regular
What to do if fast/rapid acting insulin not sufficient to control postprandial glycemia
add basal
- Levemir or NPH
- NOT Lantus
What two oral meds to use to treat GDM, what is downside to oral meds in general?
• Glyburide – sulfonyurea (Higher rates of maternal and neonate hypoglycemia)
• Metformin (Less macrosomia and lower gestational weight gain vs. glyburide)
* In general, might not be powerful enough to control glycemia
What two situations do not create Rh factor related risk
- Mom is Rh+
- Mom and Dad are both Rh-
When to administer RhoGAM
- Mom is Rh- and baby is Rh+
- Any antepartum fetal-maternal hemorrhage
- Actual/threatened pregnancy loss at any stage of gestation
- Ectopic pregnancy
*goal - prevent Rh immunization
List the 3 agents used to ripen the cervix and when to terminate use prior to starting oxytocin
Prostaglandins E2
• Prepidil Gel: (delay oxytocin min 6-12 hours after last dose of Prepidil)
• Cervidil Vaginal insert (remove 30-60 min prior to oxytocin)
Prostaglandins E1
• Misoprostil (delay oxytocin min 4 hours after admin of misoprostil)
Why treat asymptomatic bacteriuria in pregnancy?
- 30-40% will develop symptomatic UTI and pyelonephritis
- Risk if untreated: preterm birth, low birth weight, perinatal mortality
7 Treatment options for UTI in pregnancy. Note times to avoid if applicable
- Amoxicillin/clavulanate
- Cephalexin
- Cefpodoxime
- Amoxicillin – resistance may limit use
- TMP/SMX – avoid 1st trimester and at term
- Nitrofurantoin: don’t use if suspect pyelonephritis, avoid at term
- Fosfomycin: don’t use if suspect pyelonephritis
Treatment of pyelonephritis in pregnant women
- Parenteral, broad spectrum beta-lactams (ceftriaxone, cefepime, aztreonam)
- Can use low dose suppressive therapy for remainder of therapy to prevent recurrence: nitrofurantoin or cephalexin
