Chapter 36 Pain Management during Pregnancy and Lactation

Question 1

Diffusion

Answer 1

primarily passive and the drug concentration in the umbilical vein or breast milk depends on the concentration gradient, drug lipid solubility, degree of ionization and protein binding, and the diffusion capacity of the membrane (this may change as pregnancy progresses).

Question 2

The effects of the drugs on

the fetus or nursing child will depend on

Answer 2

the gestational or postconceptual age, as well as the amount and duration of
drug exposure, and the specific drug

Question 3

physiologic changes of pregnancy influence

drug absorption, distribution, and elimination

Answer 3

Changes in gastrointestinal function can alter oral drug absorption. Renal elimination is generally increased because of
an increase in glomerular filtration rate. Hepatic metabolism may be increased, unchanged, or decreased, and the increase in total body water may alter drug distribution
and peak concentrations. Protein binding is usually
decreased; however, the free drug concentration may be
unchanged because of increased drug clearance.

Question 4

The amount of drug that crosses the placenta depends on

Answer 4

maternal cardiac output, fetal cardiac output, placental binding, and placental metabolism, as well as factors that influence passive diffusion across the placenta

Question 5

Maternal plasma levels of a drug depend on

Answer 5

the site of administration
(e.g., oral, intravascular, or epidural space), the total dose,
the dosing interval, and other drugs that may be co-administered (e.g., epinephrine)

Question 6

The amount of drug to which

the fetus is exposed also depends on

Answer 6

fetal metabolism (fetal
blood carrying drugs away from the placenta passes first through the fetal liver), fetal protein binding (about half of
maternal protein binding), and the distribution of fetal
cardiac output (fetal distress results in redistribution of
blood flow to the vital organs).

Question 7

Possible adverse effects on the fetus of in utero drug exposure include

Answer 7

structural malformations, intrauterine fetal death, altered fetal growth, neurobehavioral teratogenicity, acute neonatal intoxication or neonatal abstinence syndromes

Question 8

A major determinant of the effect of a drug on the

fetus is the

Answer 8

gestational age of the fetus.

Question 9

The period of classic teratogenesis

Answer 9

corresponds with the critical period of organogenesis and begins approximately 31 days after the first day of the last menstrual period until about 71 days after the last period.

Question 10

fetal drug exposure at this

time is not risk free.

Answer 10

Fetal development, particularly the central nervous system,
continues into the second and third trimesters, and
indeed after birth.

Question 11

U.S. Food and Drug Administration Pregnancy Category System - A

Answer 11

Adequate, well-controlled studies in pregnant women have not shown
an increased risk of fetal abnormalities

Question 12

U.S. Food and Drug Administration Pregnancy Category System- B

Answer 12

Animal studies have revealed no harm to the fetus; however, there are no
adequate and well-controlled studies in pregnant women. Or animal studies
have shown an adverse effect, but adequate and well-controlled studies in
pregnant women have failed to demonstrate a risk to the fetus

Question 13

U.S. Food and Drug Administration Pregnancy Category System- C

Answer 13

Animal studies have shown adverse fetal effects and there are no adequate
and well-controlled studies in pregnant women. Or no animal studies have
been conducted and there are no adequate and well-controlled studies in
pregnant women.

Question 14

U.S. Food and Drug Administration Pregnancy Category System- D

Answer 14

Studies, adequate and well controlled or observational, in pregnant women
have demonstrated a risk to the fetus. However, the benefits of therapy may
outweigh the potential risk.

Question 15

U.S. Food and Drug Administration Pregnancy Category System- X

Answer 15

Studies, adequate and well controlled or observational, in animals and pregnant
women have demonstrated positive evidence of fetal abnormalities. The use of
the product is contraindicated in women who are or may become pregnant.

Question 16

U.S. Food and Drug Administration Pregnancy Category System- B
Drugs

Answer 16

Acetaminophen; butorphanol, nalbuphine; caffeine; fentanyl,* methadone,* meperidine,*
morphine,* oxycodone,* oxymorphone;* ibuprofen, naproxen, indomethacin;
prednisone, prednisolone

Question 17

U.S. Food and Drug Administration Pregnancy Category System- C
Drugs

Answer 17

Amitriptyline; aspirin, ketorolac; betamethasone, cortisone; codeine,* propoxyphene,* hydrocodone;* gabapentin; lidocaine; propranolol; sumatriptan; sertraline, fluoxetine; bupropion

Question 18

U.S. Food and Drug Administration Pregnancy Category System- D
Drugs

Answer 18

Imipramine; carbamazepine; diazepam; paroxetine; phenobarbital; phenytoin,
valproic acid

Question 19

U.S. Food and Drug Administration Pregnancy Category System- X
Drugs

Answer 19

Ergotamine

Question 20

Aspirin use during pregnancy may be associated with an

increased risk of

Answer 20

gastroschisis. Pregnant women should not use aspirin (.150 mg/day) regularly.

Question 21

Ibuprofen and

naproxen during the first trimester

Answer 21

do not appear to be

teratogenic

Question 22

Prostaglandin inhibitors have been associated with

Answer 22

narrowing of the ductus arteriosus in utero. Aspirin and
other prostaglandin inhibitors may decrease amniotic fluid
volume secondary to decreased fetal urine output, and they may prolong pregnancy and labor.

Question 23

An increased incidence

of neonatal intracranial hemorrhage has been found in premature infants whose mothers ingested

Answer 23

aspirin near birth. For these reasons, full-dose aspirin and nonsteroidal antiinflammatory
drug (NSAID) therapy should be avoided in the third trimester. If a mild analgesic is indicated during pregnancy, acetaminophen is the drug of choice.

Question 24

maternal opioid agonist or

agonist–antagonist exposure during pregnancy

Answer 24

There is no evidence that maternal opioid agonist or

agonist–antagonist exposure during pregnancy is teratogenic

Question 25

Chronic in-utero exposure to opioids may lead to

Answer 25

neonatal abstinence syndrome.

Question 26

treat mild or moderate pain during pregnancy

Answer 26

Acetaminophen combined

with hydrocodone or oxycodone may be used

Question 27

maternal steroid use associated with

Answer 27

orofacial clefts

Question 28

tricyclic

antidepressant drugs are

Answer 28

no evidence that tricyclic

antidepressant drugs are teratogenic

Question 29

Exposure to SSRIs in the third

trimester before delivery may lead to a

Answer 29

neonatal withdrawal syndrome, and transient QT interval prolongation. An increased risk of persistent pulmonary hypertension syndrome
of the newborn

Question 30

The anticonvulsants phenytoin, carbamazepine, and valproic acid all have been associated with

Answer 30

fetal dysmorphic
syndromes and should only be used when the risk
outweighs the benefit

Question 31

Why is Ergotamine is contraindicated in pregnancy,

Answer 31

it may

be teratogenic, and it also causes uterine contractions

Question 32

beta-blockers

Answer 32

they may be associated with intrauterine growth

retardation

Question 33

amount of drug to which an infant is exposed during

lactation- Maternal factors

Answer 33

maternal dose and dosing
interval, the elimination half-life of the drug, the infant
nursing pattern (volume and timing), and the amount of
drug that actually crosses into breast milk.

Question 34

The milk to plasma (M:P) ratio

Answer 34

is an index of the amount of drug that

is excreted into breast milk

Question 35

Breast milk is slightly more

acidic than plasma, and therefore

Answer 35

passive diffusion favors

drugs that are weak bases, lipid soluble, and have low protein binding

Question 36

volume of drugs in colostrum

Answer 36

Because the volume of colostrum is small, nursing neonates are exposed to minimal amounts of the drugs
administered to the mother in the postpartum period.

Question 37

minimize infant exposure.

Answer 37

Administration of drugs shortly after nursing, and avoiding long-acting drugs

Question 38

The following should
be considered when prescribing drugs to lactating
women

Answer 38

Is drug therapy really necessary?
The safest drug should be chosen, such as acetaminophen rather than aspirin for mild analgesia.
If there is a possibility of risk to the infant, then one should consider monitoring infant serum levels of the drug.
Having the mother take the medication just after she
has breast fed the infant or before the infant is due to
sleep can minimize drug exposure.

Question 39

Acetaminophen

Answer 39

considered the safest analgesic for nursing mothers. The infant of a mother taking acetaminophen 4 g/day was exposed to less than 5% the
therapeutic infant dose

Question 40

Opioid agonist and agonist–antagonists

Answer 40

cross freely into breast milk

Question 41

opioids

Answer 41

compatible with breastfeeding

Question 42

meperidine

Answer 42

Patient-controlled intravenous meperidine administered
for postcesarean delivery analgesia had a negative impact on neonatal neurobehavioral scores compared to morphine. The infants of nursing mothers ingesting opioids, particularly meperidine, should be monitored for adverse effects.

Question 43

prednisone

Answer 43

Less than 1% of the maternal dose of prednisone or
prednisolone is recovered in breast milk.2 Even at high
maternal doses, this is unlikely to be enough to suppress
infant adrenal function

Question 44

anticonvulsants

Answer 44

The anticonvulsants carbamazepine, phenytoin, and

valproic acid may be used safely during lactation

Question 45

Risk Categories for Drugs for Nursing Infants -Drugs for which the effect on nursing infants is unknown but may
be of concern

Answer 45

Benzodiazepines, tricyclic antidepressants, buproprion, fluoxetine

Question 46

Risk Categories for Drugs for Nursing Infants- Drugs that have been associated with significant effects on some
nursing infants and should be given to nursing mothers with caution

Answer 46

Aspirin, ergotamine

Question 47

Risk Categories for Drugs for Nursing Infants- Maternal medication usually compatible with breast-feeding

Answer 47

Acetaminophen, anticonvulsants, beta-blockers, local anesthetics,
nonsteroidal anti-inflammatory drugs, opioid agonists, opioid
agonists–antagonists, steriods, sumatriptan, sertraline, paroxetine

Question 48

Ergotamine

Answer 48

has been associated with neonatal convulsions and gastrointestinal disturbances and should not be used in nursing mothers

Question 49

The two factors that determine the possible effects of radiation exposure on the developing fetus

Answer 49

gestational age and fetal dose of absorbed radiation.

Question 50

Risks of fetal radiation exposure

Answer 50

abortion, genetic mutation,

and carcinogenesis

Question 51

At doses of less than 50 mGy,

Answer 51

the risk of abnormalities is thought to be negligible; significant risk of malformation is increased only at doses
greater than 150 mGy

Question 52

exposure should be avoided if possible until after

Answer 52

Although radiation exposure
from imaging studies generally falls below 50 mGy, exposure should be avoided if possible until after the 15th week of gestation since radiation can be lethal to the fetus or cause severe defects with doses as low as 50 mGy

Question 53

MRI is indicated during

pregnancy when

Answer 53

other nonionizing imaging methods, such as ultrasonography, are unsatisfactory, and the information obtained would otherwise require exposure to ionizing
radiation

Question 54

pelvic girdle pain

Answer 54

used to describe pain in the symphysis pubis and/or pain
in the regions of one or both sacroiliac (SI) joints and the
gluteal region, whereas pregnancy-related low back pain refers to pain in the lumbar region

Question 55

Risk factors of pelvic girdle pain

Answer 55

strenuous work, previous low back pain, or pain syndromes in a previous pregnancy.

Question 56

etiology of pelvic girdle pain

Answer 56

may be related to mechanical,
traumatic, hormonal, metabolic, or degenerative changes during pregnancy. Pain usually begins in the second trimester and resolves for most women
within several weeks to months of delivery.

Question 57

Pelvic girdle pain is usually located between

Answer 57

the posterior

iliac crests near the SI joints.

Question 58

treatments of pelvic girdle pain

Answer 58

Patient eduction, pelvic belts,
physiotherapy,and acupunture may be of benefit to some
patients

Question 59

Medication of pelvic girdle pain

Answer 59

Acetaminophen is the drug of choice for minor pelvic and back pain. The short-term use of NSAIDs may be appropriate during the first and second trimesters. Severe back pain may require opioid therapy.
Epidural steroid injection(s) may be indicated for acute radicular pain consistent with lumbar nerve root
compression