Is Terbinafine safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Terbinafine. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. A review article states that 2 women excreted totals of 0.7 and 0.2 mg in their milk after a single oral dose of 500 mg of terbinafine.[ 4 ] The details of this study were obtained from the manufacturer (Sandoz). Two healthy women aged 32 and 33 years and weighing 57.9 kg and 53.1 kg, respectively, were not breastfeeding, but had some milk production. They were each given four 125 mg tablets of terbinafine after an 8-hour fast. All milk was collected at 6-hour intervals for 72 hours after the dose. The highest concentrations of terbinafine in milk occurred in the first 6-hour aliquot and were 7.3 and 7.9 mg/L, respectively. In the 6- to 12-hour sample, milk concentrations were 2.0 and 2.4 mg/L. In the 12- to 18-hour sample, milk concentrations were 0.15 and 0.25 mg/L. After 18 hours, terbinafine was undetectable ( 150 mcg/L[5]) by HPLC assay in milk. The major metabolite of terbinafine was undetectable ( 150 mcg/L[5]) by HPLC assay in all aliquots. The cumulative amounts in milk over the 18 hours after the dose were 0.65 mg and 0.15 mg, respectively (noted above as rounded values). Milk production over this time period was 218 mL and 41 mL, respectively.[ 6 ] Using the average milk concentration values over the 24-hour period in the 2 subjects, an exclusively breastfed infant would receive 3.8% of the maternal weight-adjusted dosage of terbinafine. Some package inserts in the U.S. state that milk concentrations of terbinafine are 7-fold maternal plasma concentrations. Communication with the originator U.S. manufacturer, Novartis, indicates that this value was derived from an animal experiment (species not specified). This value is far higher than that found in humans and cannot be considered to be reliable.[ 6 ] Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
“No published information” means the studies do not exist yet — not that Terbinafine is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.