I have not heard back from you but as time is of the essence, I will leave my thoughts so you can act quickly.
Now the situation here is a worrying one. Both drugs can be used in small doses with great care in dogs, but the Acetaminophen is an overdoses here . So, while we could see the Hydrocodone cause sedation, constipation and vomiting; the Acetaminophen could cause GI upset too but also stomach ulcers, liver damage, and even breathing compromise at this high dose.
Therefore, we need to be proactive with Bella. If she just had this, you can choose to induce vomiting right now. To induce vomiting at home, you can administer 3% hydrogen peroxide orally at a dose of 1ml per pound. (2 teaspoons per 10 pounds of body weight). You can give it via dropper, syringe, turkey baster – we just want to get it in. After giving this orally, move the abdomen around or get your wee one walking about to get things mixing. This should usually lead to vomiting. If it is unsuccessful after 10 minutes then it can be repeated twice more. And if we still have no vomiting, then you'd need to consider seeing your local vet (or ER vet) so that apomorphine (a very strong injectable emetic) can be administered just get this out of the stomach and avoid any adverse issues.
As well or alternatively, you can also consider administering activated charcoal at this stage. This is available over the counter from the pharmacy (ask for the high strength version, not the one for gas) and works by binding any remaining material in the stomach. For activated charcoal, we tend to give 1-4 grams per pound every 8 hrs. This can be mixed with food to be fed or with water to syringe feed (do note that it stains, so keep it away from white carpets/clothes). This will just limit how much is absorbed and reduce the intoxication risk here.
Finally, after the above, we do want to try to address any potential GI upset here for the next 24-48 hours. To do so, you can consider offering a light diet option for a few days. Examples of an easily digestible diet include cooked white rice with boiled chicken, boiled white fish, scrambled egg, or meat baby food (as long as its free from garlic or onion powder). Ideally, we want to offer this as small frequent meals to keep the stomach settled. Further to this, we can also treat with an antacid. There are a number of antacids that are available over the counter and pet friendly. Ones we can use here include Pepcid (More Info/Dose @http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid) or Zantac (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/ranitidine-hcl-zantac). Whichever you use, we'd give this 20 minutes before food to allow absorption and of course double check with your vet before use if your wee one has any known health issues or is on any medications you haven't mentioned.
Overall, this is an overdose situation for a dog this small. Since there are some very severe and dangerous side effects, we'd want to use the above now. Any struggles to do so or if you cannot and we'd want Bella seen right away so that your vet can carry out the above plus give the antidote for the Acetaminophen and fluids to flush it out to limit harm with this.
In this situation, just in case you do wish to see an ER vet, you can check @ http://www.vetlocator.com/ or
Please take care,
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