My dog has been coughing, sneezing (regular and reverse), and has some discharge from his eyes and nose. We originally thought it was kennel cough (although he has been vaccinated) but the vet examined him and said it is a sinus infection, probably related to his endless allergies.

We had to discontinue the use of Temaril-P because he presented demodex mites on skin scrapings last month, so after he's finished with that treatment, we'll try Atopica and a hypoallergenic diet. The vet thinks that his allergies flared up again since stopping the Temaril-P, which led to the sinus problems. He prescribed 30mg of Pseudoephedrine once a day.

Is this dangerous? What kinds of side effects should I be aware of? I wasn't present for the vet visit and my husband is not great at asking those questions...

We gave the dog Pseudoephedrine for two days but his behavior was so strage that I didn't give him a pill yesterday. He looked spaced out, very depressed and sleepy, and would not eat anything. The coughing/sneezing problem is better, but I'm not sure if this is too high a dose or what... The dog is 2 years old, 34 pounds.