First, if those gums are a bit pale, we need to tread with care as that can be a sign of GI circulation issues or secondary to worms. Now I see Toby has been eating snails, so make sure he is treated for lungworm (Advocate or Milbemax) and I'd not that those treatments will cover for GI worms too. Otherwise, given his GI signs, we'd be worried he ate something he should not have (like wood) but also have to keep other issues like bacterial or viral gastroenteritis, protozoa infections, or dietary indiscretion in mind.
With this all in mind, if he is very pale or very collapsed, we'd want him sen now. Else we can try some home supportive care. To start, we can try boosting his blood sugar by rubbing a sugary syrup (ie glucose syrup, honey, karo syrup, pancake syrup, or even non-grape jam) onto the gums. This will get some sugar into your wee one and hopefully perk him up for us. After we could try to reduce nausea/vomiting with an OTC pet safe antacid [ie 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), Omeprazole (More Info/dose @ https://www.petplace.com/article/drug-library/drug-library/library/omeprazole-prilosec-gastrogard-for-dogs-and-cats/))]. 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. Though if he cannot keep it down due to nausea, that is usually a red flag that we need to bypass his mouth with injectable anti-vomiting medication from his vet.
Afterwards, we can try him with small meals of a light diet like cooked white rice with boiled chicken, boiled white fish, cottage cheese, scrambled eggs, or meat baby food (as long as its garlic/onion free). The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. Therefore, it should get more nutrients in and result in less GI upset/diarrhea. Fiber (ie canned pumpkin) and OTC probiotics (ie Benebac, Fortiflora) can be added to these meals to firm those loose stools quicker and support digestion. Furthermore, if he is very loose, you can consider trying a pet safe anti-diarrheal. As I am sure you appreciate, these would not be a cure for infectious issues; but it can still be of benefit. It will reduce diarrhea load, allow the body to absorb more water/nutrients, and soothe the upset gut. In regards ***** ***** options, the one we most commonly use is Kaolin/Kaopectate (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/kaolin-and-pectin-kapectolin-k-p)). This is available OTC at most pharmacies. Otherwise, Propectalin, Canikur, Fast Balance, and Protexin Pro-Fiber (all OTC at vets, pet stores, and even Amazon) would be another option. All will slow diarrhea and those last ones have the added bonus of providing support to the delicate good GI bacteria. So, these can be used as a short-term means of soothing his upset GI.
Finally, as dehydration is a risk we need to keep an eye on his hydration. To check that, there are a few things you can look for. Besides gum moisture, make sure his eyes aren't sunken and that he doesn’t have a "skin tent" when you lift the skin. To see how to check those dehydration signs, here is a good video ( http://www.ehow.com/video_12232503_dog-dehydrated.html ) to look at. If you do see any signs of dehydration already, that's our cue to have him seen before this becomes an additional issue (especially as it is often dehydration that makes them feel unwell).
Overall, I am concerned about the toll this is taking on Toby and his pale gums. We can try the above now for him but if he is really collapsed or really pale we'd want him seen now. And if you do want to do that, some vets in our country have office hours today. As well, I wanted to mention that most practices have contingency plans for emergency care for their patients even when they are closed. Therefore, it is worth ringing the practice. If they are open, you can get in today. If they aren't, then they will likely have a message to direct you on contacting their out of hours service. And if you don't have a vet, you can find a local one via the RCVS Register (http://findavet.rcvs.org.uk/find-a-vet/) or Vets Now (http://www.vets-now.com/find-an-emergency-vet/) who are open all nights/weekends. In any case, if you wanted to get this checked out sooner then there are options to do so.
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