I am sorry to hear you are worried about your dog. My name is Rebecca. I am a veterinarian and will do my best to help.
How recently was his creatinine checked again, or any blood tests done?
When you say his stomach, oesophagus and intestines were checked, what tests were done: Xrays, blood tests, ultrasound?
If there is no obstruction, that is good. However, vomiting can be caused by dozens of conditions: internal organ disease (liver, kidney, pancreas, intestines), pancreatitis, adrenal gland dysfunction, tumor/cancer, inflammatory bowel disease.
If Perinorm and rantac are not helping, I would try Cerenia (maropitant) for the vomiting. If blood tests were done recently, it would help me to see the results.
If Xrays were done and were normal, I would next do an ultrasound. There are many things that you can't see on Xrays that you can pick up that way.
Let me know what other questions you have. Rebecca