Ketoconazole raises
cinacalcet levels 2-fold and increased the
incidence of
cinacalcet adverse effects, probably by inhibiting the
metabolism of
cinacalcet by CYP3A4. Other potent CYP3A4 inhibitors, such as the
macrolides, are predicted to interact similarly, although they differ in their ability to inhibit CYP3A4, see
macrolides.
It may be prudent to monitor parathyroid hormone and
serum calcium more
frequently if a macrolide that potently inhibits CYP3A4 is started or stopped.