Hello and welcome to MedHelp forums. So, IBgard is something you buy yourself and is not prescribed but you should always tell your doctor or pharmacist about it. The packaging of the product and caution area indicates that this is especially true if taking any GERD products such as omeprazole. It may be okay but you will need to use caution and have doctor approval. Call your pharmacist to discuss or better yet, your doctor.
https://www.webmd.com/drugs/2/drug-167349/ibgard-oral/details