Actually, his dosage is fine if his blood levels are normal. Most dogs stay at twice a day but may need to be decreased if his levels rise to high. I would contact your veterinarian because he does have symptoms of an upper level dose which includes agitation, increased thirst, and diarrhea. See how high the numbers were and ask the veterinarian if you could decrease the dose to 0.7 twice daily and see if this helps with his current condition. If the numbers were a high normal this may be a good idea. Also, if his blood was tested and he hadn't yet had his thryoid pills or hadn't been taking them regularly this could also be an issue.

His increased thirst may be a result of the heat or other underlying condition like Cushings disease which when taking in more water may cause loose stools. If the increased thirst continues he may need to have more blood work to rule out other conditions.

Discuss these options with your veterinarian. Don't adjust his medications until you have talked with them as this could result in more internal confusion.

Thank you

Theresa