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.