Lorazepam during breastfeeding: a pharmacokinetic case report and exploratory pharmacovigilance assessment - a contribution from the ConcePTION project.

Introduction: Knowledge regarding lorazepam use during breastfeeding is limited and so are quantitative data on lorazepam transfer into human milk. Lorazepam transfer to human milk was characterized in a single case and pharmacovigilance databases were explored. Methods: A clinical lactation study was conducted in a breastfeeding mother who used lorazepam as needed for anxiety symptoms (single 1 mg oral dose, 6.5 months postpartum). Serial human milk (n = 6) and maternal plasma (n = 2) samples were collected over 24 h. Concentration-time data were used to calculate plasma and milk AUC Results: Milk concentrations ranged from 0.65 to 2.10 ng/mL, with highest levels at 1.5 h. The milk AUC Conclusion: These findings suggest low infant exposure following occasional single, low-dose lorazepam use during breastfeeding. While interpretation should remain cautious given the single-case design, the single low dose, limited plasma sampling, and milk concentrations below the validated lower limit of quantification, the available pharmacokinetic data suggest low estimated infant exposure following occasional low-dose lorazepam use. Pharmacovigilance findings provided contextual information but should not be interpreted as confirmatory evidence of safety.