Some doctors prescribe omeprazole to protect the stomach when taking Ibuprofen, but if you are using the
Doxycycline, you will not be able to have any
antacids.
If your doctor has prescribed you with these medications, he/she should have instructed you on how to correctly take them.
As you have to take the Doxy with food and drink a glass of water with it, you should be OK taking the Ibuprofen at the same time.