For et behandlingsregime med BuCy2 til voksne er der indberettet, at tidsintervallet mellem sidste perorale administration af busulfan og første administration af cyclophosphamid kan påvirke udvikling af toksicitet.
In adults, for the BuCy2 regimen it has been reported that the time interval between the last oral busulfan administration and the first cyclophosphamide administration may influence the development of toxicities.