Thank you for your patience. There are a few things that could be going on here with Stenson, but given he is licking his lips, swallowing more than usual and gagging, it is more than likely he has a gastrointestinal upset this evening. There are a few possible causes for this including anything from an acute gastroenteritis, to a toxicity or poisoning, to a bowel obstruction, internal organ issue, or even an endocrine problem. You will need to continue to keep a close eye on him, and if his breathing is still heavy, then you are best to play it safe and get him seen by your local ER vet now if you can. These breathing issues can quickly spiral out of control, so if you can get him seen now, please do.
For now, you may also want to try him with a little pepcid. The typical dose for this type of situation is 0.25mg per pound of body weight up to twice daily. You can read more about the use of Pepcid in dogs online here: http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid
As this is likely gastrointestinal in nature, you are best to with hold his food until the morning. You can then feed a bland diet like cooked boneless skinless chicken breast and boiled white rice for 2 - 3 days. Also make sure he is up to date with his deworming medication. Please keep a close eye on his mucus membranes, capillary refill time and respiratory rate as follows:
Mucus membranes - flip his lip and look at the color of his gums. They should maintain a nice salmon pink color. Get him to the emergency Vet if they appear white or very pale pink, or if they are a dark deep red color.
Capillary Refill time - this measures blood perfusion and test this by putting your thumb on his gum to apply pressure. After you release your thumb you will see the gum blanch. Capillary refill time is the amount of time it takes (in seconds) for the gum to return to a healthy pink color from the blanched white color. If 2 seconds or less don't worry - if it is taking significantly more time, again - off to the emergency Vet.
Respiratory Rate - if he is continuously panting throughout the night, this is a sign of shock and or pain and a signal for a trip to the emergency Vet.
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