The main drug-drug interactions associated with pazopanib include
CYP3A4 Inhibitors/Inducers
CYP3A4 Inhibitors1,2
Co-administration of strong CYP3A4 inhibitors increases pazopanib concentrations. Concomitant ketoconazole increased the mean pazopanib AUC(0-24) and Cmax by 66% and 45%, respectively, relative to pazopanib alone.2
QT prolongators
QTc Interval-Prolonging Drugs
QT prolongation and Torsade de Pointes has been reported with pazopanib; use with caution in patients taking anti-arrhythmic drugs or other drugs that may prolong the QT interval.2
Other Drug-drug Interactions
P-glycoprotein and BCRP Inhibitors1,2
Strong inhibitors of P-gp and BCRP may increase exposure to pazopanib.1 Co-administration of 1500 mg lapatinib (a weak inhibitor of CYP3A4 and P-gp and a potent BCRP inhibitor) with 800 mg pazopanib increased the mean pazopanib AUC(0-24) and Cmax by 50-60% compared to pazopanib alone.1,2 Co-administration with potent P-gp or BCRP inhibitors may alter the distribution of pazopanib, including distribution into the central nervous systems (CNS).2
CYP3A4, P-gp, and BCRP Inducers1,2
CYP3A4 inducers such as rifampicin may decrease plasma pazopanib concentrations. Co-administration of pazopanib with strong P-gp or BCRP inducers may alter the exposure and distribution of pazopanib, including distribution into the CNS.2
CYP3A4, CYP2D6, and CYP2C8 Substrates
Co-administration of pazopanib led to an increase of ~30% in the mean AUC and Cmax of midazolam (CYP3A4 substrate); increases of 33-64% in the ratio of dextrometrophan to dextrophan in the urine after oral administration of dextromethorphan (CYP2D6 substrate); and increases of 25%-31% in the AUC and Cmax of paclitaxel (CYP3A4 and CYP2C8 substrate).1,2
UGT1A1 and OATP1B1 Substrates
Pazopanib may increase concentrations of drugs eliminated by UGT1A1 (uridine diphosphoglucuronosyl-transferase 1A1) and OATP1B1 (organic anion transporting polypeptide).1,2
Co-administration of pazopanib 400 mg/day with cetuximab 250 mg/m2 and irinotecan 150 mg/m2 resulted in an increase of ~20% in systemic exposure to SN-38 (the active metabolite of irinotecan, and a substrate for UGT1A1 and OATP1B1).2
In a meta-analysis, ALT > 3x ULN was reported in 27% of patients given concomitant pazopanib and simvastatin, compared with 14% of those who did not use statins (p = 0.038). Statins are OATP1B1 substrates.1,2
Medicines that Raise Gastric pH
Pazopanib exhibits pH-dependent solubility.1 Co-administration of pazopanib and esomeprazole decreased the bioavailability of pazopanib by approximately 40% (AUC and Cmax).1,2