Hi there. My name is Vinay. And I m really glad you ve asked this question. Let me see if I can help you make better decisions when it comes to the timing of these meds. First off, YES, the two drugs can interact.. Prilosec can cause you to absorb less of the CellCept than you should.. This can lead to lower than expected levels of the CellCept (Mycophenolate) in your blood. That s no good. So spacing the drugs out is a really good idea. If you have been following the regime you mentioned for years and your blood tests and doctors visits are all good.. well then i m really loath to tell you to change anything.. On the other hand.. If I were advising a new patient in my hospital on the use of these drugs then I would mention this... Prilosec (Omeprazol) is a drug that PREVENTS the formation of acid and it doesn t neccesarily have to be taken an hour before eating. Actually I generaly tell my patients to take their dose right before bed. As long as you stick to any one time.. then it should work very well for you.... The advantage of this timing for the Prilosec is that it should totally avoid any interactions with the CellCept that you are taking at 5pm. Again.. I ve gotta stress how important it is not to try and fix things that aren t broken.. but if you want to make sure these two drugs are not interacting then I would call your doctor and just let them know that you would like to start taking the Prilosec at night before bed instead of at 6. I really hope this information will help you in the long run. Feel free to contact me through HCM if you think I can be of service to you in any other way. Thanks, Vin