I koncentrationer inden for området 10 til 300 µM stimulerer hydroxycarbamid ikke adenosintriphosphatase- aktiviteten in vitro af rekombinant human P- glykoprotein (PGP), hvilket indikerer, at hydroxycarbamid ikke er et PGP- substrat.
At concentrations ranging from 10 to 300 µM, hydroxycarbamide does not stimulate the in vitro ATPase activity of recombinant human P glycoprotein (PGP), indicating that hydroxycarbamide is not a PGP substrate.