Drug Use In Pregnancy (Part 1 Of Pregnancy And Lactation)

Front 1

Characteristics of Absorption in Pregnancy
1.
2.
3.
4.

Back 1

1. Decreased GI motility
2. Decreased gastric acid secretion
3. Nausea and vomiting
4. Increased skin absorption

Front 2

Blood volume increase __-__% during pregnancy

Back 2

30-50%

Front 3

Adipose tissue percentage (increases/decreases) during pregnancy.

Back 3

Increases

Front 4

How does nausea and vomiting during pregnancy affect protein stores?

Back 4

Protein stores can be decreased

Front 5

How do increased progesterone levels in pregnancy affect metabolism?

Back 5

They cause hepatic enzyme induction

Front 6

How does increased blood volume in pregnancy affect renal elimination?

Back 6

Increased blood volume leads to increased renal blood flow and increased GFR.

Front 7

How can substances be transferred across the placenta?
1.
2.
3.
4.
5.

Back 7

1. Simple diffusion (most drugs)
2. Facilitated diffusion (glucose)
3. Active transport (vitamins, amino acids)
4. Pinocytosis (immune antibodies)
5. Breaks between cells (erythrocytes)

Front 8

What factors influence drug transfer across the placenta?
1.
2.
3.
4.
5.
6.

Back 8

1. Molecular weight
- <600 (most drugs) easy
- >1,000 (ex: heparin); difficult
2. Lipid solubility (lipid soluble transfers easily)
3. Ionization
-drugs ionized at physiologic pH cross slowly (quatemary amines)
-weak acids and bases with pKa 4.3-8.5 transfer rapidly
4. Protein binding
-free, unbound drugs cross the placenta
5. Uterine and umbilical blood flow
-maternal blood pressure, cord compression, drug therapy
6. Maternal diseases
-PIH, diabetes, erythroblastosis change the permeability of the placenta

Front 9

What are some examples of the benefits of placental transfer of drugs?

Back 9

1. PCN administered to a pregnant woman with syphilis will cross the placenta and is highly concentrated in fetal blood

2. Zidovudine can prevent vertical transmission of HIV from mother to child

Front 10

What is a teratogen?

Back 10

A substance (drug or environmental agent) that leads to birth of a malformed baby

Usual manifestations of teratogenesis are restricted growth, death of the fetus, carcinogenesis, and defects in organ structure or function

Front 11

Common teratogenic effects of medications:

Back 11

1. Spontaneous abortion
2. Developmental defects
3. Malformations
4. Intrauterine growth retardation
5. Mental retardation
6. Carcinogenesis
7. Mutagenesis

Front 12

What are congenital malformations?

Back 12

Structural abnormalities of prenatal origin that are present at birth and seriously interfere with viability or physical well-being

Front 13

What is a congenital anomaly ("birth defect")?

Back 13

Malformation or functional defect (mental or physical growth retardation, CNS depression, deafness, etc)

Front 14

What are the causes of malformations?

Back 14

1. Monogenic
2. Chromosomal
3. Multifactorial
4. Environmental
5. Uknown

Front 15

Most commonly used drugs during pregnancy:

Back 15

analgesics, antimicrobials, antiemetics

Front 16

True or False: The placenta is NOT a barrier.

Back 16

TRUE - almost all drugs will cross the placenta; concentration may range from 0-100% of mother's level

Front 17

What effect does drug/substance exposure have on an embryo at the time of conception and implantation (first 2 weeks)?

Back 17

"all-or-none effect" - embryo will either die without realization of pregnancy or cells will regenerate and the embryo will not be damaged.

Front 18

When is the classic teratogenic period?

Back 18

31-70 days from last menstrual period (critical 6 weeks)
-first trimester; period of organogenesis (physical abnormalities)

(exposure > 70 days from LMP may result in functional or behavioral defects)

Front 19

FDA pregnancy risk categories apply to drugs marketed after:

Back 19

December 1983

Front 20

True or False: FDA pregnancy risk categories are easy to interpret.

Back 20

FALSE: statements are often ambiguous and difficult to interpret. The FDA may develop a more meaningful, evidence-based, narrative system for classification.

Front 21

What drug prescribed during the 50-60's caused severe limb defects (phocomelia) and other organ dysgenesis (heart, kidney, etc) and was a precursor to the Kefauver Harris Amendment?

Back 21

Thalidomide

Front 22

What should always be considered in selecting drugs for pregnant women?

Back 22

maternal morbidity and mortality; treat each case on an individual basis

Front 23

True or False: If a woman smokes during her pregnancy, there is always a risk to the fetus even if she stops.

Back 23

FALSE: If a woman stop smoking by the end of her first trimester, she is not more likely to have a low birth weight baby than a woman who never smoked.

Front 24

ACE Inhibitors

FDA Risk:

Avoid:

Complications:

Back 24

FDA Risk: C/D

Avoid: in second and third trimesters

Complications: structural changes like decreased ossification of skull and possible renal tubular dysgenesis
Other complications: oligohydramnios, craniofacial deformity, limb contractures, pulmonary hypoplasia, fetal hypotension, renal failure, anuria, death (fetal/neonatal)

Front 25

Aspirin

FDA Risk:

Complications

Back 25

(may be beneficial in low doses (81mg), avoid chronic or high doses, few associations of congenital malformations with occasional use)

FDA Risk: C/D if full dose in 3rd tri

Complications: Near term - may prolong gestation and labor
Increased risk of bleeding in the newborn (especially intracranial hemorrhage in preemie or low-birth weight infants)
Closure of ductus arteriosus may occur if used in high doses in 3rd tri

Front 26

NSAIDS

FDA risk:

Effects:

Back 26

FDA risk: D if in the 3rd tri near delivery

Effects: decrease uterine contractions
-little evidence linking these drugs with congenital malformations in the 1st tri
-3rd tri use may result in closure of the ductus arteriosus result in persistent pulmonary HTN, may also inhibit labor and prolong pregnancy

Front 27

Retinoids - Accutane

FDA Risk:

Effects:

Recommendations

Back 27

FDA Risk: X

Effects: critical period of exposure 4-7 weeks after LMP
-defects including cardiovascular and nervous systems and craniofacial abnormalities have been reported

Recommendations: 2 negative pregnancy tests before starting therapy and 2 reliable methods of contraceptive during therapy and for a month after last dose

Front 28

True or False: Epilepsy is a contraindication for pregnancy.

Back 28

FALSE: >90% of women with epilepsy have normal pregnancies

Front 29

Preconception management measures when taking anticonvulsants:

Back 29

-interactions with AED and hormonal contraceptives (recent studies show that malformations are most likely due to AED therapy)
-folic acid supplementation may decrease the risk of malformation in some women (neural tube defects)

Front 30

True or False: It is probably best to continue treatment with current drug if seizures controlled and woman becomes pregnant.

Back 30

TRUE

Front 31

True or False: Valproic acid may be associated with higher teratogenicity than other AEDs.

Back 31

TRUE: higher umbilical concentrations than maternal concentrations (perhaps because of increased placental transfer)

Front 32

What is the most studied drug in the anticonvulsant class?

Back 32

Phenytoin (catergory D) causing Fetal Hydantoin Syndrome (FHS)

Front 33

What is FHS?

Back 33

Generally associated with a variety of craniofacial defects as well as hypoplasia of the distal phalanges and small or absent fingernails.
May be due to decreased levels of epoxide hydrolase, an enzyme which increases the clearance of some potentially toxic metabolites (epoxides)

Front 34

What 2 anticonvulsants are associated with malformations seen in FHS, neural tube defects, growth and mental retardation, impaired physical-mental development, congenial heart defects, and cleft lip and palates?

Back 34

Carbamazepine (Category D) and Valproic Acid (Category D)

Front 35

Warfarin

Category:

Effects:

Avoid:

Back 35

Category: X/D

Effects: Fetal warfarin syndrome (FWS) - critical period of exposure seems to be 6th-9th week of gestation; characterized by nasal hypoplasia, depressed bridge of the nose and poorly calcified axial skeleton and proximal femur
Other features: low birth weight, congenital heart disease, deafness, optic atrophy, micropthalmia, shortened fingers, etc

Avoid: 2nd and 3rd trimesters - use may produce various CNS abnormalities resulting in blindness, deafness, hydrocephalus, seizures, spasticity, etc
Other problems: spontaneous abortion, stillbirth, prematurity and hemorrhage

Front 36

True or False: Low molecular weight heparin has a molecular weight > 3500 and does not cross the placenta.

Back 36

TRUE: Data suggests LMWH does not increase the risk of adverse birth outcomes.

(Lovenox safe for use in pregnancy)

Front 37

What are some examples of safe OTC meds to use in pregnancy?

Back 37

1. Diphenhydramine, chlorpheniramine
2. Acetaminophen
3. Pseudoephedrine
4. Guaifenesin, dextromethorphan
5. Docusate, senna, MOM
6. Loperamide
7. Calcium carbonate

Front 38

What are the 2 questions to consider when determining risks vs. benefits in taking OTC meds in pregnancy?

Back 38

1. What would happen if this condition were not treated?

2. Would the patient get well without treatment?

Front 39

What are some considerations when counseling in pregnancy?

Back 39

1. Careful not to make recommendations that cannot be supported by at least some scientific data
2. Try to provide the patient with as much detail as possible
3. Make time for your patient and give yourself time to prepare/obtain information

Front 40

What characteristics should be considered in improving communication with patients?

Back 40

1. The willingness of the pharmacist to answer questions
2. Tone of voice
3. Interest shown in the matter at hand
4. Confidence in which questions are answered
5. Terminology used