<p>Palbociclib is primarily metabolized by CYP3A and Sulfotransferase (SULT) enzyme SULT2A1. Palbociclib is a<br />
time-dependent inhibitor of CYP3A.<br />
<br />
<strong>Agents That May Increase Palbociclib Plasma Concentrations</strong>: Effect of CYP3A-Inhibitors: Coadministration of a strong CYP3A inhibitor (Itraconazole) increased the plasma exposure of Palbociclib in patients by 87%. Avoid concomitant use of strong CYP3A inhibitors (e.g., Clarithromycin, Indinavir, Itraconazole, Ketoconazole, Lopinavir/Ritonavir, Nefazodone, Nelfinavir, Posaconazole, Ritonavir, Saquinavir, Telaprevir, Telithromycin, And Voriconazole). Avoid grapefruit or grapefruit juice during Palbociclib treatment. If coadministration of Palbociclib with a strong CYP3A inhibitor cannot be avoided, reduce the dose of Palbociclib.<br />
<br />
<strong>Agents That May Decrease Palbociclib Plasma Concentrations</strong>: Effect of CYP3A Inducers: Coadministration of a strong CYP3A Inducer (Rifampin) decreased the plasma exposure of Palbociclib in healthy subjects by 85%. Avoid concomitant use of strong CYP3A inducers (E.G., Phenytoin, Rifampin, Carbamazepine, Enzalutamide, and St John&rsquo;s Wort).<br />
<br />
<strong>Drugs That May Have Their Plasma Concentrations Altered By Palbociclib</strong>: Coadministration of Midazolam with multiple doses of Palbociclib increased the Midazolam plasma exposure by 61%, in patients, compared to administration of Midazolam alone. The dose of the sensitive CYP3A substrate with a narrow therapeutic index (e.g., Alfentanil, Cyclosporine, Dihydroergotamine, Ergotamine, Everolimus, Fentanyl, Pimozide, Quinidine, Sirolimus, And Tacrolimus) may need to be reduced, as Palbociclib may increase its exposure.</p>