Temsirolimus, sirolimus and everolimus are inhibitors of the mammalian
target rapamycin (mTOR), an enzyme that regulates cell growth and
proliferation. Temsirolimus is a prodrug of sirolimus. Although mTOR
inhibitors are known to be extensively metabolized by cytochrome P450
3A4 (CYP3A4), no drug monitoring is systematically recommended
when these molecules are administered for cancer therapy in contrast to
what is recommended for organ transplantations[1]. We report on a
probable interaction between mTor inhibitors and carbamazepine (an
enzyme-inducing antiepileptic drug), in which carbamazipine leads to an
ineffectiveness of everolimus and temsirolimus therapy which is resolved
by a dose adjustment after drug monitoring.