Thank goodness no Bufferin was given since Yulaw started showing these signs. The reason I asked is because on an empty stomach this drug can cause nausea, appetite loss, and stomach ulcers. So, it is best avoided until he is 100%. Though if he is a sore lad that was really using that to cope, then we'd want his vet to start a gut safe pain relief (ie Tramadol, Buprenorphine, Gabapentin, etc). That way we can get him mobile and feeling better as we tackle this anorexia.
Now anorexia in the elderly dog can be caused by a range of issues. Common causes we need to consider include bacterial or viral gastroenteritis, dental/oral disease, pancreatitis, and ingestion of harmful items (ie toxins, plants, non-edible items). Though at Yulaw's age, we also have to be wary of systemic/organ issues and cancer as these too can trigger appetite loss and subsequent weakness.
With this all in mind, if he has been down for days, we are best to have him seen at this stage. Ideally, we'd want his vet to examine him fully, check bloods for organ issues, and start symptomatic treatment (ie fluids, gut safe pain relief, anti-nausea treatment, appetite stimulants, antibiotics, etc). That way we can counter weakness fro this starvation and dehydration as we get to the root of this for him.
Though any delay and we'd at least want to start supportive care. To start, consider treating him with an antacid. Common OTC pet safe options would be Pepcid (More Info/Dose @http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid), Zantac (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/ranitidine-hcl-zantac), or Tagamet (More Info/Dose Here @ http://www.petplace.com/article/drug-library/library/over-the-counter/cimetidine-hcl-tagamet). Whichever you choose, we’d give this 20 minutes before offering food to allow absorption. Of course, do double check with your vet if he has a known health issues or is on any medications you haven't mentioned.
If he picks up, we can then try tempting him to eat. Favorites are allowed or you can consider starting him on a light/easily digestible diet. Examples you can use are cooked white rice with boiled chicken, boiled white fish, cottage cheese, or scrambled eggs (made with water and not milk). There are also OTC vet diets that can be used (ie Hill’s I/D or Royal Canin’s sensitivity) too. The aim of these diets is that they will be better tolerated/absorbed by the compromised gut.
If he refuses but as he has no vomiting, you could also syringe feed him at this point. We can use a calorie rich diet like Hill's A/D, Royal Canin Recovery or even canned puppy food. As well, there are also liquid diets like Clinicare Canine/Feline Liquid Diet or Dogsure. All of these are nutrient dense, so a little goes a long way nutrition-wise. And these could just help get some more calories in even if we can’t get a huge volume of food in. And in the same vein, you can syringe feed fluids as you have. Though often we use Pedialyte (for its electrolytes, glucose and fluids) and we'd need to make sure he was getting at daily total of 48ml per kilogram of his body weight.
Overall, I'm quite concerned about Yulaw. There are a range of serious agents could trigger the signs we are seeing. Therefore, we’d want to start supportive care to try to get him eating. If he doesn't respond to the above within 12-24 hours; then we'd want to get his vet involved. They can assess his hydration, check bloods, make sure there is nothing in his stomach that shouldn't be there or any sinister viruses present. Depending on their findings, his vet can treat as I noted above to give him the best chance of recovery.
Please take care,
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