I would try to make contact with them to see if they wish for Coby to go to a vet's office for treatment or if they want you to try treatment at home. The fact that he's not eating or drinking and is now coughing is very concerning. Pneumonia can develop from kennel cough.
If you must address this from home,
I can give you some steps to take at home to help your companion’s stomach feel better. However, if you do not see a marked improvement from your pet or you see worsening of symptoms, they absolutely must be examined by a veterinarian. If you need help finding a location that can see your pet (even just to keep on hand), I can help. I’ll need you to provide your location as the website does not give us this.
It often helps to give medication to calm the stomach and a bland diet with higher fiber a few hours later once the medication has been given time to work. This can help to reduce the instance of nausea/vomiting, restore/improve the appetite, avoid or address changes in the stool, help to move ingested items through the GI tract, etc.
The first step is to administer a dose of regular pepcid (famotidine) every 12-24 hours. This should help with GI symptoms. You will want to give 0.5mg/pound of body weight (a 10# ***** would receive 5mg, a 5# ***** would receive 2.5mg, etc). For this, you can visit any human pharmacy and buy the OTC brand name Pepcid, or you can use the cheaper, off-brand “famotidine” that’s available. Either will be useful. If your companion is avoiding taking medication, you will likely need to using a pilling technique like this one: https://www.youtube.com/watch?v=-P6NfbxeLX0 (this video is of a dog as it shows the finer details of how to complete the action, this method can be used in dogs, cats and other mammals needing oral medications). [Note: once symptoms have resolved for at least 48 hours, discontinue the famotidine.]
2 hours following a dose of famotidine, the time needed for the medication to begin working, you can offer a bland diet. To make the bland diet, you’ll combine white or brown rice, boneless, skinless chicken breast and sufficient water for cooking in a stock pot (note: if your companion is allergic to chicken you can use a protein source they can have such as ground turkey, a filet of salmon, etc). Boil on medium until it turns to mush and the breast is easily flaked. To avoid nausea, start with small amounts to begin with and offer the amount every 2-4 hours. A few teaspoons to start is typically sufficient and you can work your way up every 2-4 hours in incremental increases until you’re sure no vomiting will be seen. If your companion requires a more palatable food, try adding in pureed baby food in chicken, turkey and similar flavors. Avoid those that contain onion or garlic in the ingredient panel. Work up to feeding exclusively until at least 3 days following the resolution of symptoms. After this, work on slowly switching back to the regular food that your companion typically eats over 10 days. My recommendation is a 10% switch every day. Day 1: 10% new food, 90% old food; Day 2: 20% new food, 80% old food; Day 3: 30% new food, 70% old food, etc. This slow switch process should minimize any risk of GI upset from changing food.
Once he's eating and drinking, then you can move on to addressing the coughing. Most kennel cough cases are viral, but secondary bacterial bronchopneumonia can develop and become a major health hazard for dogs. In some more severe cases, hospitalization may be needed. I would recommend an exam and having your vet start your companion on antibiotics to prevent more problems in the near future. As far as calming the coughing, for the time being you can use robitussin at the following dosage: http://www.peteducation.com/article.cfm?c=26+1303&aid=1395 Every vet has a different kennel cough treatment protocol and may ask you to either continue or discontinue the robitussin once examined.
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