Agomelatine in breast milk

Introduction: Under breastfeeding, pharmacotherapy of postpartum depression is restricted to a limited number of substances, though all show detectable levels in the infant's plasma. Here, we sought to investigate the levels of agomelatine in the breast milk of a patient suffering from a depressive syndrome, hypothesizing that levels of agomelatine in breast milk show a plasma-equivalent early depletion. Case report: On the first three consecutive days of treatment with 25mg agomelatine, probes of breast milk were sampled within a strict time schedule 10 minutes before (T1) and 30 (T2), 60 (T3), 90 (T4), 120 (T5) and 240 (T6) minutes after medication. For the measurement, high performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (MS/MS) was used. On all three days, concentrations of agomelatine in the milk were below detection limit of <0.1µg/l at T1. Levels on day 1 rose at T2 (0.4µg/l), T3 (0.8µg/l) and T4 (1.2µg/l) and C_max with 2.0µg/l was reached at T5. On day 2, concentrations were under detection limit at T2 and C_max of 0.78 was reached at T3. On day 3, levels of agomelatine were first detected at T4 (1.63µg/l) and reached C_max with 1.71µg/l at T5. On all three days of sampling, concentrations of agomelatine were below detection limit within 240 minutes after medication (T6). Conclusion: Our data indicate that breast-feeding is safe after a latency of 4 hours after intake of agomelatine. Studies investigating larger samples of patients including plasma probes of the child are needed in order to minimize the risk of harm to the infant.