Transfer of Zolpidem to Cord Blood and Breast Milk: A Case Series Evaluating Zolpidem Serum Levels and Outcomes in Birth and Suckling Infants.

Background: Zolpidem is used for insomnia in pregnant and lactating women. Although zolpidem has been shown to cross the placenta and to be secreted into breast milk, it would not be expected to cause any adverse effects in newborn and breastfed infants. However, there is no relevant information on serum zolpidem levels in the newborn and breastfed infant from zolpidem-treated mother. This study aimed to present the outcomes of zolpidem exposure into infant who was delivered or breastfed by a zolpidem-treated mother. Methods: In this case series, zolpidem-treated pregnant women were recruited between September 2019 and April 2022, and maternal serum, cord blood, breast milk, and infants' serum were collected, and the zolpidem concentration in each sample was evaluated. Childbirth outcomes, including 1-month health care checkup, were also evaluated. Results: Three cases were recruited during investigation period. No spontaneous abortion or preterm live deliveries occurred. Oxygen intervention was required in one term infant, but the findings resolved on postpartum day 1. No medical intervention was required in other three infants. Zolpidem was not detected in infants' serum even after breastfeeding. There are no abnormal developmental findings in any of the infants in their 1-month health checkups. Conclusions: Zolpidem transferred into fetal circulation in utero and breast milk, however no harmful findings existed in infants during pregnancy and lactation. Exposure doses through breastfeeding is small, which may be a cause of rare detection from the infants' serum. Due to the limited number of cases, larger studies and integrated review are needed.

Presence of Hypnotics in the Cord Blood and Breast Milk, with No Adverse Effects in the Infant: A Case Report.

Background: Hypnotics are frequently used for insomnia in pregnant and lactating women. This case study assessed zolpidem concentrations in the cord blood and breast milk and ramelteon concentrations in the breast milk of a woman who was treated with zolpidem and ramelteon for insomnia. Materials and Methods: Zolpidem concentrations were measured in maternal serum, breast milk, and cord blood. Concentrations of ramelteon and M-II, an active ramelteon metabolite, were measured in maternal serum and breast milk. Case Report: A 46-year-old female patient diagnosed with insomnia received 5-10 mg/day zolpidem during pregnancy and lactation and 8 mg/day ramelteon during lactation. A male infant weighing 3,329 g was born at 38 weeks' gestation, with no congenital abnormalities found during pregnancy or at birth. The infant was normal at the 1-month postpartum checkup. The maternal/placental ratio of zolpidem concentrations was 0.1 at 7.4 hours after maternal dosing, similar to that reported in previous studies. The calculated relative infant dose through breast milk based on the maximum drug concentration in breast milk at 2.2 hours after maternal dosing was 2.7% for zolpidem and 0.2% for ramelteon. Ramelteon and its metabolite (M-II) concentrations in the breast milk were equivalent to those in the maternal serum, although the infant exposure of these drugs was low for an oral dose. Conclusions: In the current case, zolpidem transferred into the placenta and breast milk, and ramelteon transferred into the breast milk. Further studies should assess the safety of zolpidem and ramelteon in fetus and breastfed infants.