‘Breast may be best’ for infants, yet, what about breastfeeding if mum needs to take medicine? Mothers frequently receive conflicting advice on this and may have unrealistic fears about the risks to their infant. This may lead to women choosing to stop breastfeeding unnecessarily or not taking the medicine that they may need. This article has been adapted for a consumer audience from one written by Sharon Gardiner, research fellow and drug information pharmacist at the Christchurch School of Medicine, originally published in Pharmacy Today magazine, July 2007.
 
Note: This article is intended as a general guide only; women should seek advice from their pharmacist or doctor if they have any concerns.

Why choose to breastfeed?

Breastfeeding has substantial health, economic and social benefits for the mother and infant. It helps with mother–infant bonding, and human breast milk is cheaper, nutritionally superior and generally more convenient than alternatives such as formula.

Human milk helps to protect infants against infectious diseases such as diarrhoea and the development of some conditions such as inflammatory bowel disease in later life. It also offers important benefits to the mother, including reduced blood loss after the birth, delayed return of ovulatory menstrual cycles [less risk of getting pregnant again too quickly] and protection against some forms of cancer.

These and other benefits have led groups such as the World Health Organization and the NZ Ministry of Health to recommend exclusive breastfeeding for the first six months of life.

In New Zealand, approximately 20% of European infants are fully breastfed at six months, with lower rates seen in Pacific Island (approx 18%) and Maori (approx 14%) infants. The benefits of breastfeeding mean that some breast milk is better than having no breast milk, but more work needs to be undertaken to improve breastfeeding rates.

Factors involved in breastfeeding

Barriers to successful breastfeeding include factors such as socioeconomic status, needing to return to the workforce, lack of antenatal education and the perception of producing an inadequate milk supply.

Health professionals such as community pharmacists and midwives can advise on methods, eg, breast pumps, bottles, milk storage, to enable the mother to continue to feed her infant breast milk after she has returned to work. They can also help mothers to manage some of the common challenges of breastfeeding, eg, cracked nipples.

In terms of treatment, medication for breastfeeding mothers can often be selected or altered so women can receive treatment, with minimal risk to their child.

What is human milk made of?

Breast milk contains fat droplets together with proteins, lactose, electrolytes and vitamins. Colostrum is produced in the immediate period after giving birth, whereas mature milk is produced from about two weeks after the birth. The latter milk has less protein and immunoglobulins [proteins that act as antibodies against disease] than colostrum, and has more fat and lactose.

Breast milk composition shows considerable variability. For example, ‘hind’ milk (milk at the end of a feed) contains up to five times more fat than ‘fore’ milk (at the beginning of a feed). This variability can influence the concentrations of a medicine in milk but, on a practical level, it matters little in terms of the overall assessment of medicine safety.

Medicine transfer into breast milk

All medicines transfer into breast milk. The only exceptions are very ‘large’ medicines, such as insulin [used in managing diabetes] and heparin [an anti-clotting agent], which do not transfer from the mother’s bloodstream into breast milk.

Breast milk tends to have a lower pH than blood (around 7.2 versus 7.4), more fat (4.5% versus 1%) and less protein (2.5% versus 19%). This means basic medicines that are fat soluble with low binding to plasma [blood] proteins, transfer readily into milk. Conversely, those that are acidic, highly protein-bound and water soluble, are less likely to transfer into milk in appreciable concentrations.

Determining risk to the infant

In determining the safety of medicines in breastfeeding, factors that should be considered include the dose of the medicine that an infant is likely to ingest via breast milk, the likely concentration of the medicine in the infant's blood, and the effect of this concentration on the infant.

In general terms, the younger or more premature the baby or infant, the longer it will take for a medicine to clear from its system. This is mainly due to the immaturity of the infant’s kidneys and the enzyme systems within the liver. Therefore, the younger the infant, the more cautious mothers should be about taking medicines in breastfeeding.

Toxic medicines – to be avoided if breastfeeding

Medicines that are traditionally viewed as contraindicated [not to be used] in breastfeeding women include anticancer agents [chemotherapy], immunosuppressants (with exceptions, eg. azathioprine in some circumstances), gold salts, amiodarone, lithium and ergotamine. These medications are highly toxic and even low infant exposure may be too much.

A number of case reports have documented problems in infants exposed to certain medicines through breast milk. For example, some beta-blockers, eg, atenolol, have been associated with bradycardia [slowing of the pulse]. Women who are breastfeeding and require a beta-blocker (eg. for migraine prevention or for high blood pressure) are better to try another agent from the class, such as metoprolol, which has lower infant exposure through breast milk.

Adverse reactions with ‘safe’ medications

Occasionally, medicines that are regarded as safe, can produce adverse reactions in some infants. For example, there are case reports of diarrhoea with 5-aminosalicyclic acid [mesalazine] and rash with paracetamol. However, both of these medications are usually regarded as safe in breastfeeding.

Overview of medicines compatible with breastfeeding

As a general guide and overview, the types of medicines generally regarded as compatible with breastfeeding are shown in the Table. This refers to both prescription medicines and some OTC (over-the-counter) medicines. They are listed under their ‘generic’ names rather than their brand names, ie, check your medicine label for the active ingredient (as an example, ibuprofen is the generic ingredient in various pain relieving preparations – brand names include Voltaren and Apo-diclofenac).

Table: Medicines that are unlikely to be problematic when breastfeeding healthy term infants

Note: This table is to be used as a guide only. Risk:benefit assessment [by doctor or pharmacist] is needed in each case.

Effect of medicines on milk supply

Another possible effect of medicine use by breastfeeding mothers, is on their milk production, with some medicines reducing or increasing mothers’ milk supply.  For example, the most commonly used oral contraceptive tablets (combined oral contraceptives) are best avoided in the early stages of breastfeeding as the oestrogen (usually ethinyloestradiol) component may suppress lactation. This is why breastfeeding women requiring an oral contraceptive are prescribed a progestogen-only pill.

Practical methods for reducing infant exposure

Mothers who require a medicine during breastfeeding should always be treated with the lowest effective dose and for the shortest possible time.  Feeding an infant immediately before the mother takes her next medicine dose is often recommended, since the medicine concentrations in breast milk are likely to be lowest at this point.

However, this may be impractical when infants feed up to two-hourly, and it is only useful for medicines with a short half-life. Infants should also be monitored for adverse effects (although these can be difficult to detect). Some things that might be noticed with some medicines include altered bowel habit and sedation.

In some circumstances, it may be appropriate to temporarily interrupt breastfeeding or alternate breastfeeding with bottle feeding of formula or previously expressed and stored breast milk. Mothers and health professionals considering this option should ensure they have appropriate specialist advice, as this approach is rarely required.

MEDICINE THERAPIES

COMMON COLDS

Coughs and colds should be managed with non-pharmacological measures whenever possible. These include rest, hydration [taking plenty of fluids], saline drops and unmedicated steam inhalations. If medicine treatment is necessary, it is best to avoid combination products in favour of individual treatments tailored to the mother’s needs. (For pain and fever relief in colds/flu, see Pain subhead below.)

Nasal decongestants /cough
Topical nasal decongestants, eg, oxymetazoline, which result in lower systemic exposure should be used in preference to oral pseudoephedrine or phenylephrine. While infant exposure to pseudoephedrine in breast milk is low, there is evidence that a single 60mg oral dose can suppress breast milk production by around 25%. There appear to be no published data as yet on the transfer of phenylephrine.

Non-pharmacological treatments, eg, throat lubrication with unmedicated lozenges, fluids etc, should be considered for treatment of cough in the first instance.

Diphenhydramine (little data but has been used extensively without problems) and codeine are reasonable choices for short-term use in breastfeeding (watch for alcohol listed in the formulation chosen and monitor the infant for signs of sedation).

There are insufficient data on dextromethorphan, pholcodine, bromhexine and guaifenesin to support their use during breastfeeding.

Throat gargles
While there is little information available on the safety of sore throat treatments, anaesthetic (numbing) throat gargles are unlikely to pose harm (be sure to spit out the medicine after gargling).

ALLERGIES

Topical treatments for local effect, such as beclomethasone nasal spray, hydrocortisone cream and cromoglycate eye drops are compatible with breastfeeding. The older antihistamines, such as promethazine and dexchlorpheniramine, are regarded as compatible (extensively used without problems), as are fexofenadine and loratadine.

GASTROINTESTINAL PROBLEMS

In general, most older anti-emetics [medications to stop vomiting] are regarded as compatible with breastfeeding because they have been used extensively without problems and exposure is expected to be low. Thus, histamine H1-receptor antagonists, eg, cyclizine, or phenothiazines, eg, prochlorperazine, are reasonable choices.

Reflux/Indigestion
Gastro-oesophageal reflux/indigestion can be treated with lifestyle measures and simple antacids. Ranitidine is also compatible with breastfeeding and may be used, if appropriate. The limited information available on the proton pump inhibitors (eg, omeprazole) indicates safety, as the dose to the infant is small and much of what is ingested through milk is likely to be degraded [broken down] in the infant's gut.

Constipation
For constipation, bulking laxatives, eg, psyllium, or lactulose, may be used. Short term use of docusate and/or senna is not expected to pose problems (but monitor the infant for altered bowel motions).

PAIN RELIEF

Paracetamol is the analgesic of choice for mild pain. NSAIDs (‘non-steroidal anti-inflammatory drugs’) are usually compatible with breastfeeding as they have minimal transfer into milk. Preference should be given to using medicines with a shorter half-life, eg, ibuprofen, diclofenac, rather than agents like piroxicam that have a longer half-life, with greater potential to accumulate in the suckling infant.

Aspirin in doses for pain and fever relief should be avoided as, although the relative dose to the infant is fairly low, there is a theoretical risk of Reye's syndrome, and safer alternatives are available.

Short term use of standard doses of opioids, such as codeine and morphine is not expected to cause harm, although the infant should always be monitored for opioid effects, eg, sedation, poor suckling. Greater caution is required if the opiate is required long term, the mother’s dose is high or the baby is premature.

A recent study with tramadol demonstrated low infant exposure through breast milk and it may be regarded as safe.

SKIN and FUNGAL INFECTIONS

For oral thrush nystatin is the treatment of choice, whereas topical clotrimazole and miconazole are appropriate for vaginal thrush and fungal skin infections.

Fluconazole is associated with a fairly high infant dose through breast milk and its safety in breastfeeding is more controversial. A single dose of fluconazole 150mg is unlikely to pose appreciable harm, although as the infant does not benefit from this form of medicine exposure, it is preferable to use topical agents in the first instance.

Other topical treatments that can be used, when indicated, include permethrin for head-lice (infestation should be confirmed first and initially consider non-pharmacological methods such as wet combing), erythromycin for acne, and aciclovir for cold sores.

LIFESTYLE MEASURES

Caffeine – avoid where possible
Caffeine in a mother’s diet has been associated with adverse effects such as irritability and altered sleeping patterns in their breastfed infants. Sources of caffeine include coffee, tea, cola drinks, some ‘energy’ drinks, and some OTC medicines (check label). Occasional caffeine intake is unlikely to cause many problems, but regular consumption is best avoided.

Smoking – quit if possible
Smoking is clearly undesirable (for both mother and baby) and should be stopped if at all possible. For mothers who continue smoking, ways to reduce infant risk include not smoking while breastfeeding, and smoking away from the baby, eg, outside. Mothers who have smoked regularly and need assistance with nicotine cravings to quit smoking, can try using nicotine patches. The nicotine patches give a lower exposure of nicotine (and other associated chemicals) to the infant than smoking does.

Alcohol should be avoided
Alcohol (ethanol) transfers readily into breast milk and it should be avoided in breastfeeding women. Alcohol has been associated with adverse effects in the breastfed infant, such as sleepiness, impaired growth and psychomotor [coordination, movement] delay. An occasional drink (eg. for celebratory purposes) may be reasonable, provided care is taken to avoid infant exposure. For example, a glass of wine could be taken after the last feed of the day if baby is down to only a few feeds per day and will not require further breast milk until the following morning.  There is no need to express and discard breast milk during this time unless this is required to help prevent breast engorgement.

As a general rule of thumb, allowing at least one to two hours after a standard drink, eg, 100mL wine or a can of beer, will allow the majority of ethanol to be eliminated from the breast milk. It is essential that breastfeeding mothers understand what a standard drink is (see www.alcohol.org.nz) as personal definitions vary.

This article has been adapted for a consumer audience from one written by Sharon Gardiner, research fellow and drug information pharmacist at the Christchurch School of Medicine, and originally published in Pharmacy Today magazine, July 2007. Copyright 2007 UBM Medica (NZ) Ltd.