Why is my dog so tired after vet injections for a skin rash?
I'm sorry to hear about Popcorn! It would be helpful to know when he went to the vet and what injections were given. His original symptoms could indicate an allergy, and if you were at the vet recently it's possible that one of the injections could cause drowsiness as a normal side effect, if an antihistamine such as diphenhydramine was given in addition to the Cetirizine (which is an antihistamine). In that case I wouldn't be as worried.
If you're still giving Cetirizine, I would recommend discontinuing and seeing if he perks up in the next 24 hours - if so, the drowsiness may have been a side effect of the medication. However, if the lethargy continues even off meds (or if he is not currently on any meds and the vet visit was more than 24 hours ago) and he's still acting lethargic, I would encourage you to take him back to the vet, as lethargy could indicate that his original rash is getting worse and he needs a change in his treatment. Hope this helps.
Updated on September 23rd, 2025