Proton Pump Inhibitors (PPI):In a dedicated drug-interaction trial in healthy subjects (N=15),lansoprazole (a PPI) decreased neratinib's Cmax by 71% and AUC by 65% when compared t neratinib given alone. The main active metabolites were not measured. It is recommended that concomitant use with treatments that alter gastrointestinal pH such as PPls and Hrreceptor antagonists should be avoided. Neratinib can be administered w ith antacids if administered at least 3 hours after antacid.