US Pharm. 2013;38(9):43-46.
than 80% of pregnant women take OTC or prescription drugs during
pregnancy, with only 60% of these patients consulting a health care
professional when selecting a product. Common pregnancy-associated
conditions include cough, cold, allergies, gastrointestinal disorders,
and pain. The cough, cold, and allergy products most widely used during
pregnancy are antihistamines, decongestants, antitussives, and
expectorants. Current updates to the immunization schedule include
administering tetanus, diphtheria, and acellular pertussis (Tdap)
vaccine with each pregnancy. Influenza vaccination should also be
recommended for all pregnant women and can be given in any trimester.
The decision to treat pregnancy-associated conditions should be based on
a number of factors, including safety, symptom severity, and potential
for quality-of-life improvement.
The prevalence of medication use during pregnancy is
widespread and on the rise. More than 80% of pregnant women take OTC or
prescription drugs during pregnancy, with only 60% of these patients
consulting a health care professional when selecting a product.1
There is a delicate risk-benefit estimation concerning the health of
both the mother and the fetus that must be considered in the use of
drugs during pregnancy.
A study investigating the use of prescription, OTC, and
herbal medicines in a rural obstetric population of 578 participants
found that over 90% of the patients took either prescription and/or OTC
medication.2 A larger cohort study (multicenter, urban) found
that 64% of expectant mothers had been prescribed a drug other than a
vitamin or mineral supplement at some point during their pregnancy.3
Medication use during pregnancy can generally be
attributed to preexisting conditions such as hypertension or cardiac
problems, pregnancy-associated conditions such as nausea and vomiting,
or acute conditions such as seasonal allergies or bacterial infections.
Among the most frequently used medications in pregnancy are antiemetics,
antacids, antihistamines, analgesics, antimicrobials, diuretics,
hypnotics, and tranquilizers.4
Do the Benefits Outweigh the Risks?
Drug use during pregnancy continues to remain a major
concern due to the unknown effects on mother and fetus. Physicians are
faced with difficult situations as they have very little information to
help them decide whether the potential benefits to the mother outweigh
the risks to the unborn fetus. To help guide physicians in their
selection and interpretation of the risks associated with the drug, the
FDA introduced a drug classification system in 1979 (TABLE 1).4-7
Most information provided in this classification is derived from animal
studies and uncontrolled studies in humans such as postmarketing
surveillance reports. To date, very few well-controlled studies have
been conducted in pregnant women, most likely due to ethical
considerations. Two important limitations of the classification include5-7:
- All new FDA-approved medications are classified as Category C
- There are no FDA regulations requiring further studies
or seeking more data; therefore, changes in the classification are rare.
In addition, the classification is often not changed when new data
Approximately 20 to 30 of the most commonly used drugs are
identified as teratogens, with 7% of the more than 1,000 medications
listed in the Physicians’ Desk Reference classified as Category X.7
Some of the commonly used drugs with proven teratogenic effects in
humans are warfarin, isotretinoin, valproic acid, and tetracycline
antibiotics. The timing of fetal exposure to a drug is critical to the
likelihood of an adverse effect occurring. Most of the major body
structures are formed during the first trimester, and exposure during
this time could lead to structural teratogenic effects.8 Some drugs have different FDA categorizations based on the trimester of pregnancy.
As pharmacists, we play a vital role in educating and
counseling pregnant women on the risks associated with a drug. Informing
a pregnant woman of the risks and possible fetal defects can reduce the
number of complications. Furthermore, it is our responsibility to
ensure that other health care professionals are familiar with the
current literature available on the safety of drugs administered during
pregnancy. This article will present a concise discussion of common
medications used to treat pregnancy-associated conditions, including
cough, cold, and allergies; pain; and gastrointestinal (GI) disorders;
as well as provide an update on the current immunization recommendations
Cough, Cold, and Allergy
It is very common for women to experience cough, cold, or
allergy symptoms during pregnancy. The use of multiple OTC medications
to treat these symptoms increases from the first to the third trimester.
According to one study, 92.6% of the obstetric population interviewed
self-medicated with OTC medications.2 The common cold is
typically caused by numerous viruses and, therefore, is usually
self-limiting. Pregnant women should be advised to first try
nonpharmacologic treatments such as a saline nasal spray, the use of a
humidifier, and increased hydration.9,10 The most commonly
used cough, cold, and allergy products include antihistamines,
decongestants, antitussives, and expectorants (TABLE 2).1
It appears that the older sedating antihistamines, also known as first-generation agents, are safe in pregnancy. The recommended
agent is chlorpheniramine (Chlor-Trimeton), which is Category B.
According to the Collaborative Perinatal Project, chlorpheniramine use
during pregnancy was not associated with an increased risk of
malformations.7 Diphenhydramine (Benadryl) is also an option
in patients who need symptomatic relief from allergy or cold symptoms.
It is also Category B and was not associated with an increased risk of
malformations; however, it can cross the placenta and has been reported
to have possible oxytocin-like effects at high doses when used during
The newer nonsedating or second-generation
antihistamines, such as loratadine (Claritin), fexofenadine (Allegra),
and cetirizine (Zyrtec), have not been extensively studied. Cetirizine
may be alternative to chlorpheniramine in the second or third trimester
if a first-generation antihistamine is not tolerated.9,10
Administration of both inhaled and oral decongestants
occurs during pregnancy. Pseudoephedrine (Sudafed) and phenylephrine
(Sudafed PE) are the most common oral OTC decongestants used, with 25%
of pregnant women using pseudoephedrine as their oral decongestant of
choice.11 However, its use should be avoided during the first
trimester due to associated risk of defects from vascular disruption
known as gastroschisis. Inhaled decongestants such as
oxymetazoline (Afrin) and phenylephrine (Neo-Synephrine) are both
Category C and appear to be safe for use.
The primary cough remedy used during pregnancy is
dextromethorphan (Delsym). Many studies suggest that there is no
association between dextromethorphan use and an increased risk of birth
defects.9,10 However, many of the OTC products containing dextromethorphan also contain alcohol and should be avoided during pregnancy.
Guaifenesin (Mucinex) is the expectorant typically found
in most OTC cold medications. Its use appears to be safe during
pregnancy, with the exception of the first trimester.9
Acetaminophen is the most commonly used OTC analgesic in
pregnancy, with at least 65.5% of women taking it at some point during
pregnancy and 54.2% taking it during the first trimester.12
The use of single-ingredient acetamino-phen products during pregnancy
has not been associated with increased risk of a broad range of birth
defects.13-15 Due to its antipyretic effects,
single-ingredient acetaminophen products have been associated with a
decreased risk of some birth defects arising from febrile infection
Aspirin and other nonsteroidal anti-inflammatory drugs
(NSAIDs) should be avoided if possible during pregnancy. A recent study
found that although the use of NSAIDs in early pregnancy does not appear
to be a major risk factor for birth defects, there were a few moderate
associations between NSAIDs and specific birth defects.16
Another major concern is the increased risk of miscarriage that has been
associated with the use of nonaspirin NSAIDs during pregnancy.17
The use of NSAIDs during pregnancy is also associated with premature
closure of the ductus arteriosus, fetal renal toxicity, and inhibition
of labor.4,15,18 Although there are limited reproductive
studies involving the use of narcotic analgesics in human pregnancies,
these drugs have been used in therapeutic doses for many years by
pregnant women without a link to an elevated risk of birth defects.15,19
The use of opioids should be reserved for pain that is not managed with
acetaminophen and, when possible, the lowest effective dose should be
The most common GI problems that occur during pregnancy
include nausea, vomiting, acid reflux, diarrhea, and constipation. Drug
therapy may be required when lifestyle modifications cannot provide
adequate relief of symptoms.
While nausea and vomiting are common indicators of early pregnancy, an extreme manifestation of the condition is termed hyperemesis gravidarum.
Severe hyperemesis gravidarum complications—including weight loss
>5% of initial body weight, electrolyte imbalance, and dehydration—
are the second most common reason for prenatal hospitalization.20
A variety of medications with different mechanisms of action that have
been used to treat nausea and vomiting of pregnancy are listed in TABLE 3.20-22
Acid reflux is another common problem estimated to occur in 30% to 50% of all pregnancies.23
Due to the pressure on the uterus, acid reflux during pregnancy is less
likely to respond to lifestyle modifications such as elevation of the
head when sleeping, eating small frequent meals, or avoiding eating
within 3 hours of bedtime.24 OTC antacids are considered the
agents of first choice with the exception of magnesium trisilicate
(Gaviscon) and sodium bicarbonate (Neut), which should be avoided during
pregnancy. Long-term use of high-dose magnesium trisilicate has been
associated with increased risk of fetal nephrolithiasis, hypotonia, and
respiratory distress; sodium bicarbonate has been associated with
metabolic acidosis and fluid overload.23 A variety of agents that have been used to treat acid reflex during pregnancy are listed in TABLE 3.20-22
Diarrhea and constipation are also frequent problems associated with pregnancy. TABLE 3 lists agents used to treat these conditions.20-22
Castor oil and mineral oil should be avoided for the treatment of
constipation. Alosetron (Lotronex) is only indicated for irritable bowel
syndrome (IBS)–associated diarrhea. Bismuth subsalicylate
(Pepto-Bismol, Kaopectate) should be avoided in pregnancy because the
salicylate moiety can lead to increased perinatal mortality.21
Women who are considering pregnancy or those already
pregnant should be advised on the importance of receiving vaccines.
Informing these patients of the benefits of receiving certain
vaccinations can significantly reduce the occurrence of preventable
diseases. With the many vaccines available, and pharmacists at the front
lines as immunizers, it is important to discuss the agents utilized for
specific groups of patients. The following are a few of the current
recommendations for vaccine use during pregnancy.
The most current update to the immunization schedule was
the recommendation to administer tetanus, diphtheria, and acellular
pertussis (Tdap) vaccine with each pregnancy during the 27th to 36th
week of gestation. This is different from prior recommendations that
were dependent upon previous vaccination history. Waiting until the
second trimester is reasonable to minimize concerns about possible
adverse reactions.25 Healy et al concluded that the infants
of mothers immunized either before their pregnancy, or in early
gestation, displayed insufficient antibodies to aid in infant protection
from disease.26 Furthermore, the antibodies that were
transferred were lost within a 6-week period, which could possibly place
the infant at risk of infection.26
Influenza vaccination should be recommended for all
pregnant women for prevention of seasonal influenza and can be
administered in any trimester. It is most beneficial when given as early
as available in the flu season.27 The immunizations
contraindicated during pregnancy are live vaccinations, which include
influenza (LAIV); measles, mumps, and rubella (MMR); varicella; and
Most women will take medications at some point during
pregnancy. It is important to consider the risks and benefits of drug
therapy to both mother and fetus. The decision to treat should be based
on a number of factors, including the safety profile of the drugs in
question, symptom severity, and potential for quality-of-life
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