Ketoconazole, a potent CYP3A4 inhibitor, increases the AUC of
aprepitant 5-fold. The manufacturer recommends caution when
aprepitant is used with any potent inhibitor of CYP3A4, (such as
clarithromycin and telithromycin). Fosaprepitant, a prodrug of
aprepitant, would also be expected to interact with the
macrolides in this way.
The lowest dose of
aprepitant may be appropriate. Counsel patients about adverse effects (e.g. hiccups,
fatigue,
constipation, headache). Other
macrolides may also interact, although it seems unlikely that they all will, see
macrolides.