Diabetes insipidus in dogs is a rare disorder of water balance that causes extreme thirst and very large amounts of dilute urine. It isn't related to diabetes mellitus (sugar diabetes).1,2 It happens when the body makes too little antidiuretic hormone (ADH), which is central diabetes insipidus, or when the kidneys don't respond to ADH, which is nephrogenic diabetes insipidus.3,1 Central diabetes insipidus is most often of unknown cause but can follow head trauma, pituitary tumors or cysts, or pituitary surgery.4,3 Nephrogenic diabetes insipidus is usually acquired, from kidney infection, Cushing's disease, liver disease, some drugs and other illnesses.3,4 Because many more common diseases cause heavy drinking, vets rule those out first.1,5 Central diabetes insipidus is usually controlled with a synthetic antidiuretic hormone medication. Never restrict water for a dog with diabetes insipidus.1,2
See your vet promptly if your dog:
- Suddenly drinks and urinates far more than usual, or starts having accidents1
- Shows signs of dehydration, weakness or confusion, especially if water was unavailable1,3
- Has heavy drinking along with head trauma, seizures or behavior changes3
Keep fresh water available at all times. Dogs with diabetes insipidus can dehydrate quickly without it.1,2
What the Research Says
- Safer testing. A 2026 review says the water deprivation test carries a real risk of dehydration and high blood sodium, and that a medication trial is a safer practical alternative.5
- No breed pattern. In 60 dogs with central diabetes insipidus at UC Davis, 25 breeds were affected, with ages from 7 weeks to 14 years.4
- After pituitary surgery. Diabetes insipidus after pituitary surgery was temporary in 78% of dogs.4 A 2022 study of 127 dogs having pituitary surgery for Cushing's disease found high blood sodium in 46.5% afterward.6
- How much is too much. Drinking more than 100 mL per kg of body weight a day confirms excessive thirst.4
Types
- Central diabetes insipidus: the pituitary gland releases too little ADH. Causes include unknown (idiopathic) disease, head injury, pituitary tumors and cysts, inflammation and pituitary surgery.3,4
- Nephrogenic diabetes insipidus: the kidneys don't respond to ADH. Inherited forms are rare and show up by 8 to 12 weeks of age. Acquired forms come from kidney infection, Cushing's disease, liver disease, leptospirosis, electrolyte problems and some drugs.4,3
Signs
Other Causes of Heavy Drinking
Diabetes insipidus is uncommon, so vets check for more likely causes first:4,7,3
- Diabetes mellitus. See diabetes in dogs.
- Kidney disease. See kidney disease.
- Cushing's disease. See Cushing's disease.
- Pyometra in unspayed females. See pyometra.
- Liver disease, high blood calcium and Addison's disease
- Medicines such as steroids, diuretics and anticonvulsants
- Psychogenic (behavioral) drinking, which "is said to occur in hyperactive young dogs that are left alone during the day"7
Diagnosis
Blood tests and a urinalysis come first. Very dilute urine is an early clue: in complete diabetes insipidus, urine specific gravity is 1.006 or lower.3,5 Some vets use a modified water deprivation test, done gradually and under close supervision, and only in dogs that aren't dehydrated and don't have kidney disease. Merck warns that "an abrupt withdrawal of water is not recommended."3,4 Many vets instead give a trial of antidiuretic hormone medication and watch whether drinking drops.5,1 CT or MRI may be used if a pituitary tumor is suspected.1
Treatment
- Central diabetes insipidus: a synthetic antidiuretic hormone medication given as eye drops, nose drops, tablets or injections, usually for life1,2,4
- Nephrogenic diabetes insipidus: treat the underlying cause. Thiazide-class diuretics and a low-salt diet may help.1,3
- Always provide water. Merck says "water should not be restricted."2,3
Some dogs with central diabetes insipidus can live without medication as long as they always have water, though they'll urinate a great deal.3
Outlook
Diabetes insipidus usually can't be cured, except in some cases after head injury or surgery, but it "can usually be successfully controlled."1,4 The outlook depends on the cause.1,4 Without water or treatment, dogs can become severely dehydrated, which can lead to stupor, coma and death.1
Frequently Asked Questions
Is diabetes insipidus the same as diabetes in dogs?
No. Diabetes insipidus is a water-balance problem and doesn't involve blood sugar or insulin.
How is diabetes insipidus treated in dogs?
Central diabetes insipidus is treated with a synthetic antidiuretic hormone medication. Nephrogenic diabetes insipidus is managed by treating the cause.
Should I limit my dog's water?
No. Never restrict water unless your vet is running a supervised test.
Can a dog live with diabetes insipidus?
Yes. Many dogs live well with treatment and constant access to water.
What breeds get diabetes insipidus?
There's no clear breed pattern for central diabetes insipidus. Inherited nephrogenic forms are very rare.
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Sources and further reading
This article was rewritten and fact-checked on October 23, 2026 against current veterinary references and specialist guidelines:
- Weir M, Williams K, Downing R, Ward E. Diabetes Insipidus in Dogs. VCA Animal Hospitals, updated June 2025.
- Greco DS, Kritchevsky JE. Disorders of the Pituitary Gland in Dogs. Merck Veterinary Manual (Dog Owners), updated September 2024.
- Greco DS. Diabetes Insipidus in Animals. Merck Veterinary Manual, updated September 2024.
- Canine and Feline Endocrinology, 4th ed. Chapter 1: Water Metabolism and Diabetes Insipidus. Elsevier Saunders, 2015.
- da Silva CEF, Oliveira IM. The diagnostic challenges of diabetes insipidus in dogs: A narrative review of the water deprivation test and complementary biomarkers. Open Veterinary Journal, 2026.
- Del Magno S, vanRijn S, Azzariti S, Valtolina C, l'Ami J, Meij BP. Plasma sodium and potassium concentrations after hypophysectomy in dogs with corticotroph adenomas. Journal of Veterinary Internal Medicine, 2022.
- Kooistra H. The Diagnostic Approach to Polyuria in the Dog. EVC Voorjaarsdagen, Amsterdam (IVIS), 2013.
About this article
Last updated : written using the Merck Veterinary Manual, VCA, a veterinary endocrinology textbook, IVIS proceedings and 2022 to 2026 research, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.
This page is for general information and is not a substitute for an exam by your veterinarian.
