Ketamine and esketamine during breastfeeding: a systematic review of human pharmacokinetic, infant and lactation outcomes

Ketamine is used in anaesthesia and analgesia, and esketamine nasal spray is licensed as a rapidly acting treatment for treatment-resistant depression; both uses overlap with the postpartum period. We synthesised human evidence on transfer into milk, infant exposure, infant outcomes and breastfeeding outcomes.

The review was registered in PROSPERO (CRD420261364557) and reported according to PRISMA 2020. Databases and registers were searched from inception in January 2026; supplementary sources and citation searching were completed on 21 August 2026. Eligible primary human reports measured drug or metabolite concentrations in human milk, outcomes in breastfed infants, or lactation outcomes after postpartum exposure. Certainty was rated with GRADE principles separately for each of these questions and for infant systemic exposure. Pooling was not undertaken because the studies were not comparable.