1.8 Medications

Key Points - Case Study A
Joanne, aged 32, a regular patient, comes to see you when she is 12 weeks pregnant with her first baby. She has just returned from a trip around Australia and her pregnancy was confirmed by a doctor in the town they were in at the time. She has copies of her baseline blood tests with her and all are normal.
Would you discuss breastfeeding at this visit?
- Topic 1.1: Discussing breastfeeding
- It is important that doctors discuss infant feeding decisions and breastfeeding with women early in a pregnancy rather than waiting until the third trimester or after the baby is born.
What information would you give?
- Topic 1.2: What information to give
- When discussing infant feeding with mothers it is important to note that alternatives to breastfeeding have many undesirable outcomes.
Why do breastfeeding alternatives have different effects?
- Topic 1.3: Effects of Breastfeeding alternatives
- These effects are due in part to the presence in breast milk of substances and systems that act against infections and inflammation.
What are mothers' common and valid concerns about breastfeeding?
- Topic 1.4: Common breastfeeding concerns
- Exploring her concerns and providing information and reassurance is useful in allaying anxiety and prepares the parents for their changing role.
Would you examine her breasts at this visit?
- Topic 1.5: Breast examination
- Examine Joanne's breasts now and again in the third trimester. Examining a mother's breasts and nipples early in pregnancy emphasises the importance of breastfeeding, provides reassurance for most women that they are 'normal', allows the identification of any variations that may cause problems.
What are the contraindications to breastfeeding?
- Topic 1.6: Contraindications to breastfeeding
- There are very few conditions when women should be discouraged from breastfeeding, including active tuberculosis, HIV, human T-cell leukaemia virus Type 1, brucellosis, some medications, illicit drug use and classic galactosaemia and some inborn errors of metabolism in the infant.
What conditions may be related to poorer lactation outcomes?
- Topic 1.7: Conditions related to lactation outcomes
- Common problems are previous lactation failure, hormonal problems and obesity.
Joanne's sister-in-law developed hyperthyroidism when she had been breastfeeding her last baby and was told that she would have to wean so that she could commence taking medication. Joanne asks you whether it is common for women to have to wean to be treated for medical conditions. What would you tell her about medication use in breastfeeding women?
- Topic 1.8: Medications
- There are very few medical conditions for which a mother needs to cease breastfeeding so that she can be adequately treated. In nearly all situations a mother can continue to breastfeed while she is on medication.
Joanne's sister-in-law developed hyperthyroidism when she had been breastfeeding her last baby and was told that she would have to wean so that she could commence taking medication. Joanne asks you whether it is common for women to have to wean to be treated for medical conditions. What would you tell her about medication use in breastfeeding women?
There are very few medical conditions for which a mother needs to cease breastfeeding so that she can be adequately treated. Within most classes of drugs, or drugs used to treat a specific condition some are better options for breastfeeding women than others. In nearly all situations a mother can continue to breastfeed while she is on medication. Medications that are absolute contraindications to breastfeeding have been mentioned previously.
Has the infant already been exposed in-utero? | An infant is exposed to much higher levels of a medication in-utero than through breast milk. |
Is the medication necessary? | Can a topical or local preparation be used rather than an oral or parenteral preparation? |
How much of the drug would the infant receive in a day? What is the relative infant dose? | As a rough guide a relative infant dose of 10% is deemed to be compatible with breastfeeding. Consider the following:
|
Is this medication used in infants? | |
What is its oral bioavailability? | Medications given parenterally to the mother are unlikely to be absorbed by the infant no matter how much is present in breast milk. |
How effective will the infant be in excreting what has been absorbed? | Newborns have 33% of the adult capacity for drug excretion while a 7 month old has a similar capacity to an adult. Infants who are premature or sick have reduced capacity. |
Are there other drugs that will be just as effective but are potentially a safer option for a breastfeeding woman? |

The amount of drug transferred into milk will depend on the dose, timing and formulation of the medication
- Medications given once a day should be taken around the feed just prior to the infant's longest sleep.
- Medications taken more frequently should be taken around the time of a feed (authorities differ whether just before or just after is most appropriate) to allow for drug peaks to fall prior to the next breast feed.
- Expressing and discarding milk will not necessarily reduce the amount of the medication in milk. In most instances the concentration of a drug in milk mirrors that in maternal plasma. As the mother metabolises the drug the milk level will fall.
Obtaining correct and up-to-date information
Recommendations that a mother should not breastfeed while taking a specific medication are common when limited data is available.
Generic sentences such as “ drug A is excreted into breast milk and caution should be used when administered to breastfeeding women
” or “ Alternative feeding arrangements should be considered
” are often encountered in product information sheets although recommendations often vary between different references.
A recent survey of 10 frequently used sources of information regarding breastfeeding and medication use found wide disparity in the recommendations between the sources for 14 medications. 1
Using a reference or source with expertise in evaluating the risks of medications in breastfeeding women is essential. The following list is not inclusive, but contains resources that have reputable information and recommendations.
Books:
Hale TW. 2012 Medications and mothers' milk: a manual of lactational pharmacology. 15th ed. Hale Publishing. Amarillo.
BriggsG, Freeman R, Yaffe S. 2011 Drugs in pregnancy and lactation - a reference guide to fetal and neonatal risk. 9th ed. Lippincott, Williams & Wilkins, Philadelphia.
Lawrence RA, Lawrence RM. 2011. Breastfeeding: a guide for the medical profession. 7th ed. Elsevier Mosby, Maryland Hts.
Useful public access databases/websites:
Lactmed - drug and lactation database.
Infant risk center (Dr T. Hale)
UKMiCentral Medicines Information : Drugs in human milk - quick reference guide.

Case Study Activity
Think about what your response would be to the scenario presented, write it into the exercise, then submit it and read the suggestions given.
Notes
- # Akus M et al. (2007) Lactation safety recommendations and reliability compared in 10 medication resources