It does indeed sound like your dog has a problem with excess bile. Perhaps your vet prescribed Zantac (Ranitidne). You can give it every 8 to 12 hours. You give 0.25 to 1mg per pound of body weight. So, a 20 pound dog would get roughly a little under a 1/3 tablet of the 75mg. Ranitidine reduces the amount of acid produced.
Dogs can also take prilosec (omeprazole). You can give it every 24 hours at a dosage of 0.25 to 0.5mg per pound of body weight. This is an over the counter medication as is pepcid. Prilosec works by blocking many of the active stomach pumps that produce acid before they produce the acid. It has to be given consistently.
Pepcid is another over the counter choice and it works by reducing the amount of acid the stomach produces. Read about Pepcid dosages and usage information here:
These are common medications used for excess bile and acid reflux. You might try probiotics to help get good bacteria into the dog's system which will aid in digestion and help with the acid issue. A popular choice is Fortiflora available in many pet stores. It won't hurt the situation at all.
Dogs can also develop problems with their gall bladders which can cause vomiting as well. You would likely need different imaging to diagnose that. Read about this here:
I'd talk to your vet about trying a different medication. I'd also feed about 4 meals a day evenly spaced out and maybe another small one right at bed time to keep your dog from having an empty stomach overnight. This helps as well.
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