Transfer of carisoprodol to breast milk

There is no published information on the transfer of the centrally acting m uscle relaxant carisoprodol and its active metabolite meprobamate into brea st milk. The objective of this study was to quantify the excretion of caris oprodol and meprobamate in human milk and estimate the dose received by bre ast-fed infants. The concentrations of carisoprodol and meprobamate were me asured in breast milk on 4 consecutive days at steady-state conditions in o ne woman using carisoprodol 2100 mg/d. The average milk concentrations were 0.9 mug/mL for carisoprodol and 11.6 mug/ml, for meprobamate. Based on the milk concentrations measured, the absolute dose ingested by an exclusively breast-fed infant could be estimated at 1.9 mg/kg per day, and the relativ e dose would be 4.1% of the weight-adjusted maternal dose. No adverse effec ts were observed in the infant, but the infant was partly fed with formula because of insufficient maternal milk production. Thus, the authors conside r that at least during prolonged use, lactation is generally inadvisable un til more clinical data are available.