Drug Interactions between Kisqali Femara Co-Pack and naldemedine

MONITOR: Coadministration with ribociclib may increase the plasma concentrations and pharmacologic effects of drugs that are substrates of CYP450 3A4. The proposed mechanism is decreased clearance due to ribociclib-mediated inhibition of CYP450 3A4 metabolism. In healthy study subjects, administration of midazolam, a sensitive CYP450 3A4 substrate, with multiple 400 mg daily doses of ribociclib increased the midazolam peak plasma concentration (Cmax) and systemic exposure (AUC) by 2.1-fold and 3.8-fold, respectively, compared to midazolam administered alone. When given at a clinically relevant dose of 600 mg daily, ribociclib is predicted to increase midazolam Cmax and AUC by 2.4-fold and 5.2-fold, respectively.

MANAGEMENT: Caution is advised when ribociclib is used concomitantly with drugs that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever ribociclib is added to or withdrawn from therapy.

MONITOR: Coadministration with moderate inhibitors of CYP450 3A4 and/or moderate or potent inhibitors of P-glycoprotein (P-gp) may increase the plasma concentrations of naldemedine, which is primarily metabolized by CYP450 3A4 to nor-naldemedine and to a minor extent by UGT1A3 to naldemedine 3-G. Both metabolites have demonstrated antagonistic activity for opioid receptors, but with less potency than the parent drug. Naldemedine is also a substrate of the P-gp efflux transporter. According to the product labeling, administration of naldemedine with 200 mg once daily itraconazole, a potent CYP450 3A4 and P-gp inhibitor, increased naldemedine peak plasma concentration (Cmax) by 12% and systemic exposure (AUC) by 191% compared to naldemedine administered alone. When administered with 200 mg once daily fluconazole, a moderate CYP450 3A4 inhibitor, naldemedine Cmax and AUC increased by 38% and 90%, respectively. When administered with a single 600 mg dose of cyclosporine, a potent P-gp but weak CYP450 3A4 inhibitor, naldemedine Cmax and AUC increased by 45% and 78%, respectively. Increased exposure to naldemedine may precipitate opioid withdrawal symptoms such as hyperhidrosis, lacrimation, rhinorrhea, chills, diarrhea, abdominal pain, anxiety, insomnia, irritability, restlessness, and yawning.

MANAGEMENT: Caution is advised during concomitant use of naldemedine with moderate inhibitors of CYP450 3A4 and/or moderate or potent inhibitors of P-glycoprotein (P-gp). Patients should be closely monitored for potential opioid withdrawal symptoms as well as other adverse effects of naldemedine.