Changes in Drinking and Urinating Habits of a Cat

A thirst increase often indicates medical significant problems. Some of them need urgent attention.

Is the animal thirstier, has less appetite and, if female, is it lethargic? (With or without vaginal festering?) . YES
Go to the veterinary NOW

Does he have more thirst and has lost weight? YES
Go to the veterinary within 24 hours

Does he have more thirst and urinates more? YES
Go to the veterinarian within 24 hours

Does he have more thirst and urinates less? YES
Go to the veterinarian within 24 hours

Does he have more thirst and vomits? YES
Go to the veterinarian within 24 hours

Does he have more thirst and he suffers diarrhea YES
Go to the veterinarian within 24 hours

Does he have more thirst and fever? YES
Go to the veterinarian within 24 hours

Does he drink absolutely nothing? YES
Go to the veterinarian within 24 hours.