Posted on behalf of the Breast Cancer Care nursing team
As you mention the Electronic Medicines Compendium states that antacids have been investigated when taken with capecitabine. It states that antacids may slightly increase plasma concentrations of capecitabine. You can read this in section 4.5 from the link below, although this information hasn’t been written from a patient information perspective:
However proton pump inhibitors (PPI’s) such as omeprazole aren’t strictly antacids. They work by reducing the amount of acid your stomach makes, as supposed to antacids which do not stop your stomach producing acid; rather they try to neutralize or protect against what is already there. See below for further information:
I have contacted Roche to ask if they know of any interaction with capecitabine (Xeloda) and proton pump inhibitors and they said they were not aware of any and that it was therefore an individual prescribing decision. I’m not sure why your pharmacist was suggesting taking the drugs two hours apart: perhaps just a precaution. I’m sorry I was unable to find the information on the Roche website that you mention.