Why should tacrolimus not be given during treatment with Trecondi (treosulfan)?

Tacrolimus should not be given during Trecondi (treosulfan) treatment because of potential CYP3A4/CYP2C19 interactions involving narrow-therapeutic-index medicines; depending on timing and pharmacokinetics, dosing concomitant medicines 2 hours before or 8 hours after the 2-hour treosulfan infusion can reduce interaction potential to “no interaction”.