To the Editor: In his review of drug information for thyroid-related medications, Stockigt noted the “outdated advice that antithyroid drugs are not compatible with breastfeeding.”1 However, outdated product information is not unique to antithyroid drugs. Product information rarely states that the drug is safe or advisable for breastfeeding women.

Many women receive medicines in the postpartum period: a UK study found that 54% of women were given a drug in hospital and 55% were given a prescription by their general practitioner.2 Yet many breastfeeding women who need medicines are being given incorrect advice, as illustrated by the experience of my podiatrist, Janet.

Breastfeeding was going well when, at 4 months postpartum, Janet fell down a flight of stairs. Neither the ambulance officers nor the metropolitan emergency department registrar were willing to administer any pain relief except paracetamol (“unless you are prepared to wean”) — although Janet was in excruciating pain with a fractured 12th rib. At 7 months postpartum, Janet was hypertensive despite treatment. Regardless of her strong desire to continue breastfeeding, her GP and specialist informed her that she needed to change medication and therefore would have to stop breastfeeding.

Janet’s case illustrates two issues: firstly, a breastfeeding woman was denied necessary medication because she was breastfeeding, and secondly, her infant was denied continued breastfeeding because of maternal medication. Apparently none of the health professionals sought expert help with decision making surrounding medicines and breastfeeding. Janet encouraged me to use her story to educate other health professionals.

For the vast majority of maternal medications, the amount of medication an infant would receive through breastfeeding is less than 1% of an infant dose. In general, if the medication is safe to use in infants, it will be safe for the breastfeeding mother. Only a small number of medications are contraindicated during breastfeeding: these include antineoplastic agents, ergotamine, methotrexate, cyclosporin, and radiopharmaceuticals.3

Information is available about safe use of medicines while breastfeeding (Box). The sources listed in the Box have reviewed the available evidence on individual drugs and given recommendations on whether they are safe to use during lactation. In general terms, they have followed the recommendations for evaluating appropriateness of off-label medicines as suggested by a recent New South Wales working party.4 Medicines used during pregnancy are given safety ratings and the information is available online.5 Australian clinicians need to access such guidance in relation to safe prescribing for breastfeeding women.