Stoffer, der er potente hæmmere af CYP3A4- aktiviteten (f. eks. proteasehæmmere, antimykotika, makrolidantibiotika, nefazodon, selektive serotonin re- uptake- hæmmere), øger blodkoncentrationerne af sirolimus.
Substances that are potent inhibitors of CYP3A4 activity (e. g., protease inhibitors, anti-fungals, macrolide antibiotics, nefazodone, selective serotonin re-uptake inhibitors) increase sirolimus blood concentrations.