US Pharm. 2007;32(7)(OTC suppl):8-12.

The American Academy of Pediatrics (AAP) policy statement on breast-feeding recommends that women breast-feed their infants exclusively for at least the first six months of life and suggests trying to breast-feed for the first 12 months of life.1 One of the many objectives of Healthy People 2010 is to have 75% of mothers initiating breast-feeding, 50% of mothers breast-feeding for the first six months, and 25% of mothers breast-feeding for the first 12 months.2 According to the 2005 National Immunization Survey, only five states have achieved all three of these objectives, with 21 states achieving the goal of mothers initiating breast-feeding.2 As health care professionals encourage more women to breast-feed, medication use while breast-feeding will increase. It is important for pharmacists to understand the effects of OTCmedications in women who are breast-feeding in order to make appropriate recommendations.

Transfer of Drugs into Breast Milk
Most medications will transfer into breast milk; however, the degree of transfer depends on several factors. Drugs may transfer into milk if they attain high concentrations in maternal plasma, have a low molecular weight (<500 Da), are low in protein binding, and are lipid soluble.3 During the first week of breast-feeding, when colostrum is produced, there are large gaps between the alveolar cells that enhance the passage of drugs into milk. However, the quantity of milk produced at this time is low (<30 to 100 mL/day), so the absolute dose transferred is minimal.3 After the first week, the presence of prolactin closes the gaps, reducing the entry of most maternal drugs and other substances into the milk compartment.3

Safety Data and Breast-feeding
Unlike pregnancy, which has established FDA categories for medications, breast-feeding lacks standardized risk categories. Most of the data on medications and breast-feeding are from scientific literature. More information on lactation risk categories can be found in Tables 1 and 2.

Given the lack of safety standardization, other recommendations for using medications while breast-feeding include choosing drugs with short half-lives, high protein binding, low oral bioavailability, or high molecular weight.3 Other options to decrease infant exposure to the drug are taking the medication immediately after breast-feeding and avoiding long-acting formulations. Additionally, a clinician should choose a medication with published safety data rather than a newly introduced medication.


Analgesics
Many OTC options for analgesics are available. Acetaminophen is routinely used for fever and pain in infants, and levels excreted into breast milk are expected to be less than the dose given to infants.3-5

Of the NSAIDs, ibuprofen is considered the drug of choice for breast-feeding women and is used routinely in infants. While ibuprofen is excreted into breast milk, the concentration and subsequent transfer to the infant are very low.3,6,7

Naproxen should be used cautiously in breast-feeding women due to its long half-life. One case report documented prolonged bleeding, anemia, and thrombocytopenia in a 7-day-old infant whose mother was taking naproxen while breast-feeding.3,8

Aspirin is excreted into breast milk in low concentrations. It has a slower excretion from breast milk than from plasma.7 The risk of Reye's syndrome due to aspirin in breast milk is unknown.3,9 Alternative therapeutic options are recommended; if aspirin is taken, the mother should avoid breast-feeding for one to two hours after the dose.9


Allergy, Cold, and Cough Preparations
Antihistamines: All OTC antihistamines are known to be excreted in breast milk, and their sedating effects may also be seen in infants. While it is known that diphenhydramine is excreted into breast milk, the concentration and infant transfer are unknown.3,10 The d-isomer of brompheniramine, dexbrompheniramine, is considered usually compatible with breast-feeding by the AAP, though effects in the infant may occur and include sleep disturbances and excessive crying.3,11 Levels of chlorpheniramine in breast milk are unknown; however, small doses of 2 to 4 mg are considered acceptable.3,12 Clemastine is a long-acting antihistamine that should be used cautiously due to its association with significant effects on infants, including irritability, refusal to feed, and neck stiffness.1,3,13 All of the sedating antihistamines have the possibility of causing sedation in the infant and/or decreasing milk supply, especially when taken in conjunction with a decongestant, and should be used with caution.

Currently, the only nonsedating OTCantihistamine that is available is loratadine, which is excreted in breast milk. However, concentrations in the infant are low and considered safe.3,14 Due to its nonsedating effect, loratadine is the preferred antihistamine.

Decongestants: The two OTC oral decongestants available are pseudoephedrine and phenylephrine. Due to new regulations regarding the sale of pseudoephedrine, many cough and cold preparations have reformulated their products to contain phenylephrine.

Phenylephrine, an ingredient in pediatric cough and cold preparations, is considered safe. While excretion into breast milk is unknown, it is unlikely to be excreted into breast milk in large quantities due to its poor bioavailability. The effect of phenyl­ ephrine on milk production and supply is also unknown; therefore, this medication should be used with caution in women with limited milk production. 3,15

Pseudoephedrine may be preferred due to lack of data on phenylephrine and breast-feeding but should be used cautiously in lactating women with limited milk production. Pseudoephedrine is excreted in breast milk and has been shown to decrease milk production and possibly cause irritability in infants.3,16

Nasal decongestants are an alternative to systemic decongestants. Most OTC products contain either oxymetazoline or phenylephrine. Excretion in breast milk of oxymetazoline is unknown. However, due to their local activity and minimal systemic absorption, nasal decongestants may have a low concentra­tion in breast milk and are preferred over systemic oral decongestants.17

Cough Medications: Dextromethorphan is a common cough suppressant used in cough and cold preparations. Although dextromethorphan has not been studied in breast-feeding, expected concentrations in breast milk would be low.3,18

Guaifenesin is used as an expectorant in many formulations of cough and cold products. Due to lack of data on excretion in breast milk and lack of efficacy, it is best to recommend a product without guaifenesin.3,19

Cough preparations may also contain alcohol. While alcohol is considered compatible with breastfeeding by the AAP, lactating mothers should choose alcohol-free or low-content alcohol products.

Drugs for Gastroesophageal Reflux Disease (GERD) or Heartburn
Medications available for the treatment of GERD include histamine2 receptor antagonists (H2RAs) and the proton pump inhibitor (PPI) omeprazole. All four H2RAs are generally considered safe in breast-feeding infants. The AAP states that cimetidine is compatible with breast-feeding. 1 However, due to cimetidine's hepatic enzyme inhibition and many drug interactions, other drugs are preferred.20 Famotidine, a preferred H 2RA, is used in newborn infants.3,21 Ranitidine becomes concentrated in milk; however, the dose is subtherapeutic and can be used safely by a nursing mother.3,22

Omeprazole is the only PPI available OTC. There is limited information on the use of omeprazole and lactation; however, an infant would not systematically absorb any omeprazole from the breast milk due to omeprazole's acid lability; the drug would be destroyed by the infant's stomach before reaching the blood circulation. 3 Thus, omeprazole would not be expected to cause any adverse effects in breast-fed infants.23

Bismuth subsalicylate is not considered compatible with breast-feeding due to the salicylate absorption. 24 The AAP states that salicylates have been associated with significant effects on some nursing infants and should be given to nursing mothers with caution.1

The use of oral antacids containing calcium, aluminum, and magnesium are generally considered safe for use during breast-feeding. Although, there are no published studies on the use of these medications, the amount ingested is not expected to be more than what is found in infant foods.24

Gastrointestinal Medications
Gastrointestinal medications include agents used for the treatment of diarrhea, constipation, and flatulence. Loperamide, which is used for the treatment of diarrhea, is generally considered compatible with breast-feeding due to minimal oral absorption.1,3,25

Docusate is a common OTCstool softener. It is minimally absorbed orally, and minimal transfer to breast milk would be expected. As a precaution, mothers who take docusate should watch for loose stools in the infant.3,26

Other OTC medications for the treatment of constipation are the stimulant laxatives bisacodyl and senna and the bulk-forming laxative psyllium. Bisacodyl has not been studied in breast-feeding; however, due to its minimal systemic absorption, it would not be expected to cause adverse effects in the breast-fed infant and is considered compatible.3,27 Senna, a strong laxative, is compatible with breast-feeding. Although older reports indicated an increased incidence of loose stools in infants who were exposed to senna, newer reports have not shown this adverse effect with current senna products.3,28 Psyllium is not absorbed systemically and, therefore, does not enter breast milk. It is considered compatible with breast-feeding.24

Simethicone, used for the treatment of intestinal gas, is commonly used in infants. The drug is not absorbed systemically and thus would not pass into breast milk. Simethicone is considered compatible with breast-feeding.7,24,29

Medications for Vulvovaginal Infections
OTC intravaginal antifungals for vaginal candidiasis include miconazole, clotrimazole, butoconazole, and tioconazole. Miconazole and clotrimazole have been studied in breast-feeding mothers and infants and are unlikely to have adverse effects on a breastfed infant due to limited absorption from the vaginal tract. 3,30,31 Miconazole or clotrimazole are not rated by the AAP; however, fluconazole and ketoconazole are considered compatible with breast-feeding. 1 Neither tioconazole nor butoconazole hasbeen studied in breast-feeding mothers or infants. Therefore, it is recommended to use an alternative drug that has been studied.32,33

Smoking Cessation Products
Although women are encouraged to stop smoking before becoming pregnant, some may continue to smoke through pregnancy and decide postpartum to stop smoking. OTC products for smoking cessation include the nicotine patch, gum, and lozenge. These products generally produce plasma nicotine levels that are significantly lower than those seen when individuals smoke one pack of cigarettes a day.34

Studies have shown that the absolute infant dose of nicotine and its metabolite, cotinine, decrease by about 70% from when subjects were smoking or using the 21-mg patch to when they were using the 7-mg patch.3 The use of the nicotine patch had no effect on the milk intake by the infant.3 Nicotine gum may produce large variations in nicotine levels; therefore, it is recommended to refrain from breast-feeding for two to three hours after using the gum product. 3,34

The AAP does not make a recommendation for or against nicotine replacement products in breast-feeding women.1 Similarly, no information on the nicotine lozenges and breast-feeding is available. Prior to recommending a nicotine replacement product, pharmacists should consider referring the patient to a pediatrician.

Miscellaneous Agents
Dermatologic products are commonly used by individuals on a daily basis. Some of the more common topical OTC products include antihistamines, corticosteroids, and antibacterials.

Information on the topical antihistamine diphenhydramine is unavailable; however, systemic absorption from topical formulations is less than that with oral formulations.

Although the topical corticosteroid hydrocortisone has not been studied in breast-feeding, it is unlikely that its short-term use would pose a risk to the infant.35 Breast-feeding women should use the lowest strength available and apply to the smallest area affected. If applied to the breast, creams are preferred over ointments, and the breasts should be washed prior to breast-feeding.35 The AAP rates prednisone and prednisolone as compatible with breast-feeding, but does not rate topical hydrocortisone.1

The most common topical antibiotics are neomycin, bacitracin, and polymixin B. All three of these products are considered compatible with breast-feeding.7,36,37,38


Conclusions
When recommending a medication, it is important to choose medications with known information and those least likely to have effects on the infant. It is important to educate the nursing mother on potential side effects her infant may experience.

References
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2. Centers for Disease Control and Prevention. Breast–feeding practices. Results from the 2005 National Immunization Survey. Available at: www.cdc.gov/ breast–feeding/data/NIS_data/data_2005.htm. Accessed May 10, 2007.
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