CONCLUSION
Everolimus is a subtrate of CYP3A4 and P-glycoprotein whose blood
concentrations can be seriously affected by drug interaction at that
level, eventually implying underexposure to everolimus. Therefore, TDM
should be used whenever potential metabolism drug-drug interactions are
detected in cancer patients to monitor drug levels and to contribute to
achieve the optimal Css ultimately associated with better response and a
lower toxicity profile.