Poor girl. It sounds like she has a chronic intestinal problem that requires chronic use of medication. I think we need to investigate further what the underyling problem is so that we have a better idea here. Many diseases can cause the symptoms we are seeing with Touta such as Pancreatitis, inflammatory bowel disease, malabsorption disease, or even lymphoma jsut to name a few. The next best step would be to do an abdominal ultrasound on her to get a better look. Also bloodwork analysis would be best to do as well to get an idea of her overall health.
In the meantime, continue giving her her medication since it does seem to stabilize her well. I would also consider getting her on a prescription diet food for gastrointestinal problems such as Royal Canin Selected Protein PR
https://www.royalcanin.com/us/dogs/products/vet-products/canine-selected-protein-adult-pr-dry-dog-foodPrescription diets are best when dealing with chronic disease in pets. I hope that you get to the bottom of Touta's illness soon! Best wishes and take care.