Methods and compositions are described for the modulation of central nervous system and/or fetal effects of substances. Methods and compositions are described for the modulation of efflux transporter activity to increase the efflux of drugs and other compounds out of a physiological compartment and into an external environment. In particular, the methods and compositions disclosed herein provide for the increase of efflux transporter activity at blood-brain, blood-CSF and placental-maternal barriers to increase the efflux of drugs and other compounds from physiological compartments, including central nervous system and fetal compartments.