(R)‐ and (S)‐methadone and buprenorphine concentration ratios in maternal and umbilical cord plasma following chronic maintenance dosing in pregnancy

Abstract

The transfer of the individual methadone enantiomers to the foetal circulation is stereoselective. Infants born to buprenorphine maintained women are not exposed to a greater proportion of the maternal dose compared with methadone and may be exposed to relatively less of the maternal dose compared with infants born to women maintained on methadone during pregnancy.