Diabetes in dogs: symptoms and treatment

I don’t have a diabetic dog. The journal that Diabnostic grew out of started with a cat: Manishka was diagnosed in October 2025. But dog profiles have already appeared in the journal, and “diabetes in dogs” is a frequent search. The record fields are the same — the disease is different. And the differences are what matter most right now: a dog has almost no chance of getting off the injections, but there is a clear routine with which these dogs live for years.

How to Tell if Your Dog May Have Diabetes

The first thing an owner notices is water. The bowl empties faster, the dog wakes you at night and begs to go outside, puddles in the hallway. Appetite grows while weight creeps down. Thirst, hunger and weight loss are the most common picture with which dogs arrive at a diagnosis. In cats the set of signs is the same, but a dog almost always adds cataracts.

Cataracts are the calling card of canine diabetes. They are a common and characteristic sign, and clouding of the lens can develop quickly. The dog bumps into doorframes, catches the ball less well, is cautious at dusk. The owner writes it off as age; the vet looks at the blood sugar. Clouding happens even in dogs already on injections.

If it’s a female, the date of her last heat matters. During diestrus — the period after a heat — the body’s tissues respond to insulin less well, and diabetes during this period may turn out to be either temporary or permanent. Diestrus is a well-known risk factor in unspayed females, and tell the vet about the last heat at that same visit.

How the Diagnosis Is Confirmed

A single high blood sugar reading carries more weight in a dog than in a cat. Stress hyperglycemia — when blood sugar spikes from the car ride and the clinic visit itself — is a well-documented problem in cats; in dogs it is far less common. That’s why a single blood draw lies less often.

But the diagnosis is still made by the vet, not by a test: it takes persistently high blood glucose plus glucose in the urine plus those same signs — thirst, hunger, weight loss. If the results are scarce or doubtful, the vet may order a fructosamine test. It shows what the average blood sugar was over the previous one to two weeks, and a one-off episode of stress practically doesn’t distort it. Interpreting results is the vet’s job; what counts as high blood sugar in the first place and what the normal range for dogs is — that’s covered in the article on normal blood sugar in cats. After that, at home: a notebook, a glucose meter and two alarms.

How Diabetes in Dogs Differs From Diabetes in Cats

A cat often has a chance to back out of it: insulin is still being produced, and some cats stop needing injections once the disease is controlled — this is covered in detail in the article Diabetes in Cats. With a dog it’s different. By the time of diagnosis, the pancreatic cells that produce insulin are usually already dead: in dogs they are lost quickly and progressively, most often because the dog’s own immune system destroys them, less often because of pancreatitis. That’s why canine diabetes always requires insulin: AAHA states it plainly. Remission in ordinary, non-hormonal diabetes in dogs is rare — don’t count on the injections being stopped. Pancreatitis, meanwhile, is a frequent companion and a possible cause of the disease, and that’s one more argument against choosing the food yourself.

The exception is an unspayed female. If diabetes coincides with diestrus, spaying is not an “optional extra” but a mandatory part of managing such a dog: it removes the hormonal resistance to insulin and supports remission. How much the injection requirement will change afterward — the vet decides based on tests and an examination.

The goal of control, meanwhile, is modest and clear: the thirst and frequent urination are gone, weight is stable, no symptomatic hypoglycemia. How long dogs with diabetes live — I can’t give you a number: it depends on age at diagnosis, cataracts, the kidneys, whether the dog was already brought in in ketoacidosis. Without insulin, dehydration and ketosis come quickly. With insulin and steady feeding, years happen — I won’t promise them to any particular dog.

What You Will Have to Do Every Day

The routine comes down to a few habits.

Bowl = injection. Two equal meals a day, each at the moment of the insulin injection. Blood sugar shouldn’t spike after the bowl, so the food needs to be one that smooths out the post-meal rise. Dogs do well on any complete and balanced diet with consistent timing and portions, but with concurrent conditions — kidneys, pancreatitis — the diet is different, and which one is the vet’s call.

The dog didn’t eat — call the vet before the injection. An injection on an empty stomach risks hypoglycemia, but a missed meal is not a reason to decide about the injection on your own: the vet may have their own plan for that situation. Don’t inject out of habit — call the vet before the injection and follow their plan.

A doubtful injection. The dose didn’t all go in, or you’re not sure the injection actually landed — no guessing. Agree with the vet in advance what to do about a doubtful injection; then the episode goes by instructions, not by instinct. Injection technique and the list of questions for the vet are in the article Insulin for Cats: the questions are the same — which drug, which syringe concentration, what to do if the injection didn’t take. The answers for a dog will be different — you can’t plug in a cat dose, which is why there are no numbers here.

The vet moves the dose. A flat curve is rare, and a one-off high reading while the dog feels fine is no reason to tinker with the dose in the middle of the night. The vet adjusts the dose from the records, conservatively, never on a single number.

To the two alarm clocks for injections, add the walk: the injection, the bowl and the outing don’t always coincide with the end of the daily walk. I can’t tell a dog story in the first person — ours is a cat one: Manishka’s Story. Readings can go into the Diabnostic journal — it keeps dogs too: same fields, same charts.

Dangerous Low Blood Sugar: What to Do

The main everyday risk of insulin is hypoglycemia, a drop in blood sugar that goes too far. Most often it happens when the dose turned out too large or the dog didn’t eat after the injection. You need to know the signs on sight: lethargy, drowsiness, odd behavior, a wobbly gait, weakness, trembling, up to seizures.

Act immediately. If the dog is conscious and swallowing — give food with carbohydrates. If it’s responding poorly or trembling — rub a little corn syrup on the gums and get to the vet at once; don’t wait for morning. With a sluggish dog, don’t put anything in its mouth: liquid can get into the airways. Even if the dog has come around, show it to the vet the same day: an episode means the dose or the regimen needs to be reviewed. A full walkthrough of mild and severe episodes is in the overview article Diabetes in Cats — the action plan there is the same for both.

Sources

1. Behrend E, Holford A, Lathan P, Rucinsky R, Schulman R. AAHA Diabetes Management Guidelines for Dogs and Cats. J Am Anim Hosp Assoc. 2018;54:1–19.