Dear JD,
Did he do something to injure himself today?
Did he have a long walk?
Is he breathing normally?
What color are his gums?
Is he eating and drinking normally?
Thank you.
You can actually give him two 325 mg aspirins total based on his weight. That is not even the maximum dose.
You already gave him 1/2. So you can give him another 1 1/2 tablets.
If he is not better in the morning, I recommend you take him to the vet for x rays.
He may have hip arthritis. www.VeterinaryPartner.com/Content.plx?P=A&A=1916
Intervertebral disc disease. www.VeterinaryPartner.com/Content.plx?P=A&A=2373
Or another problem.
Veterinarian
Veterinarian in practice for 10 years. Compassionate, Caring, Experienced.