Drug-induced adverse reactions via breastfeeding: a descriptive study in the French Pharmacovigilance Database

Most drugs are excreted in maternal milk and may therefore be ingested by children during breastfeeding. Data concerning the safety of the use of drugs by breastfeeding women are patchy, and almost nothing is known about this issue for many drugs.

The aim of this study was to describe the adverse drug reactions of drugs transmitted in breast milk on the basis of the data collected in the French Pharmacovigilance Database. All spontaneous reports of adverse drug reactions (ADRs) in breastfed infants recorded in the National Pharmacovigilance Database by the 31 French regional pharmacovigilance centres between 1984 and June 2011 were investigated.

Between January 1985 and June 2011, 276 adverse drug reactions in 174 breastfed children were notified to the French Pharmacovigilance Network. The most frequently reported adverse drug reactions were neurological (28.6 %) and gastrointestinal (20.3 %). Sixty-five of the adverse drug reactions recorded were considered to be serious (37.4 %). The results of our study confirm that certain drugs were frequently implicated in serious adverse drug reactions. Two cases of ADRs (1.1 %) had a 'certain' causality score (I4) and 13 (7.5 %) a 'likely' score (I3). The suspected drugs include antiepileptic drugs, opiate analgesics and benzodiazepines. These results also demonstrate that some drugs that were thought to be anodyne or for which no data were available, such as ketoprofen and hydroxyzine, may be implicated in adverse effects. Finally, these data show that certain drugs, like pseudoephedrine, which should not be used during breastfeeding, were nevertheless implicated in several of the adverse drug reactions recorded.

This study shows that ADR via breastfeeding are rarely reported due to low awareness or low occurrence of ADR via breast milk. These results highlight the need for additional pharmacokinetic, clinical and epidemiological studies, given the paucity of published data. They also demonstrate the need to improve information for the general public about drugs and self-medication during breastfeeding.