More precisely, ADH is made in the hypothalamus and released into the bloodstream from the posterior pituitary. Central disease can involve a problem at either stage.
When to see a vet urgently
Seek prompt treatment if a cat drinking or urinating excessively develops any of the following:
- Severe weakness, staggering or collapse.
- Inability to drink or repeatedly vomiting water back up.
- Altered consciousness or seizures.
- Repeated attempts to urinate without passing urine.
Failure to pass urine can mean obstruction and is not the usual excessive urine production of diabetes insipidus. You can find a vet near you.
Overview
Antidiuretic hormone, also called vasopressin or ADH, regulates the kidneys' ability to concentrate urine and retain water. If there is too little hormone or the kidneys do not respond, they lose the ability to concentrate urine and large amounts of dilute urine leave the body. Your cat urinates frequently and drinks a lot to replace lost fluid.
Diabetes insipidus is uncommon in cats but can develop at any age. It is dangerous because untreated disease leads to dehydration, electrolyte disturbances and other complications.
Dehydration risk is particularly high if your cat cannot access water or drink enough. Some studied cats with otherwise stable central disease can replace losses by drinking when water is continuously available. Treatment needs are nevertheless assessed by a vet. Do not remove the water bowl to reduce urination.
Diabetes insipidus is different from diabetes mellitus, or sugar diabetes. Diabetes mellitus involves insulin and blood glucose; diabetes insipidus disrupts water regulation. Similar symptoms therefore do not mean the same medicines are needed.
Causes
There are two forms, distinguished by how they develop:
Central diabetes insipidus results from insufficient ADH production or release. Causes include:
- Head injuries.
- Tumours around the hypothalamus and pituitary.
- Inflammation, including encephalitis and meningitis.
- An idiopathic form, where the cause remains unknown.
Nephrogenic diabetes insipidus develops when the kidneys do not respond to ADH. Causes include:
- Congenital receptor defects, uncommon in cats.
- Chronic kidney diseases.
- Hypercalcaemia and hypokalaemia.
- Poisoning and medicine-related kidney damage.
Nephrogenic disease means a reduced response to ADH. It may result from another illness rather than necessarily being a separate congenital defect. However, not all increased urination with kidney disease is called diabetes insipidus. The underlying cause needs investigation because it determines treatment.
Risk factors
- Previous brain injuries.
- Brain tumours.
- Chronic kidney diseases.
- Electrolyte disturbances, for example with hormonal diseases.
- Age over 7–8 years, with disease more common in older cats.
No clear age, sex or breed predisposition is known for diabetes insipidus. The age above is therefore not a diagnostic risk threshold. Central cases have also been described in young cats. Increased drinking in an older cat needs investigation, but a much more common disease may be responsible.
Typical symptoms
- Marked thirst, with clearly increased drinking.
- Frequent, excessive urination.
- Pale, almost clear, dilute urine.
- Weight loss.
- Tiredness, apathy and irritability.
- Possible episodes of dehydration, with dry mucous membranes and reduced skin elasticity.
At home, you may notice a rapidly emptying bowl, larger wet litter clumps or drinking from new places. Urine appearance does not reliably measure specific gravity. Passing a large total volume differs from constant tray visits producing only drops. The latter can relate to urinary pain or obstruction.
Severe forms cause marked dehydration, neurological symptoms and declining general condition.
Complications and consequences
Untreated diabetes insipidus can lead to:
- Chronic dehydration.
- Electrolyte imbalances.
- Kidney damage.
- Reduced quality of life.
- Death in severe cases.
Excessive drinking is usually an attempt to replace lost water. Preventing it can rapidly worsen the situation. New vomiting, refusal to eat or inability to reach water in a cat with diagnosed diabetes insipidus requires review of the plan.
Diagnosis at the vet
Diagnosis is demanding because other causes of excessive urination and thirst must first be excluded, including diabetes mellitus, chronic kidney disease, hyperthyroidism and hyperadrenocorticism. Investigations include:
- Basic urinalysis showing low specific gravity and no glucose.
- Blood biochemistry, including electrolytes and kidney and liver values.
- A water deprivation test, performed only under close veterinary supervision.
- A desmopressin trial, using a synthetic ADH analogue to distinguish central and nephrogenic forms.
- Head MRI or CT if a pituitary or hypothalamic tumour is suspected.
A water deprivation test is neither a home experiment nor an ordinary first investigation. It can be dangerous and is not performed in an already dehydrated animal or one with kidney disease. A carefully monitored desmopressin trial is now often preferred once more common causes have been investigated.
Blood and urine results are interpreted together. Dilute urine without glucose does not establish diabetes insipidus alone. Investigations consider glucose, kidney function, calcium, potassium and the thyroid where needed. Report all medicines and supplements, because some increase drinking and urination. Specialist investigations are selected according to findings.
During a desmopressin trial, changes in drinking, urine volume and concentration are monitored according to your vet's plan. A clear response supports ADH deficiency, but partial forms and other diseases can complicate interpretation. Trying medicine yourself therefore does not replace investigations.
Head imaging is considered if history or findings suggest central nervous system damage. A previous head injury followed by thirst, for example, is important information. Not every cat's underlying cause can be identified, in which case disease may be classified as idiopathic.
Treatment
Treatment depends on the form:
- Central diabetes insipidus: desmopressin as eye drops, nasal spray or tablets, and fluids if dehydrated.
- Nephrogenic diabetes insipidus: treatment of the underlying cause, such as correcting electrolytes or managing CKD, a diet restricted in salt and protein, and vet-prescribed medicines to improve urine concentration.
- Both forms require monitoring of fluid balance and adequate fluid intake.
Desmopressin replaces the missing hormonal effect. Product, route and treatment changes are agreed with your vet; human instructions are not directly applicable to a cat. Response varies, and drinking and urine concentration are monitored alongside health. Nephrogenic disease may respond poorly to the same medicine.
The diet for nephrogenic disease is chosen according to the underlying cause and nutritional status. Do not reduce salt or protein randomly at home, and not every cat receives the same restricted diet. With underlying CKD, feeding should support kidney care and adequate nutrition.
Dehydration needs vet-planned fluids and electrolyte monitoring. Water loss and electrolyte disturbances cannot be safely corrected simply by changing medicines yourself. The treating vet assesses whether hospital care is needed.
Home care and monitoring
Keep fresh water continuously within easy reach and ensure access to the litter tray. Provide drinking places in several familiar locations. Do not punish puddles or urination outside the tray: very high urine volume or poor health may be responsible.
Your vet may ask you to measure drinking. Record the starting amount and water added, and report other animals using the bowls or your cat drinking elsewhere. This makes measurement uncertainty clear. Gathering observations does not require reducing water.
Also record appetite, urination, weight changes and medicines actually given. Report unsuccessful administration or returning symptoms. Response-based checks remain necessary even when your cat otherwise seems bright.
Prognosis
Disease can often be managed once the form is identified and water access ensured. Central disease often requires long-term medicines. Some cases following injury may resolve, and secondary nephrogenic disease may improve when its cause is treated. An underlying tumour or other serious illness affects prognosis. Reducing or stopping medicines is always considered according to follow-up.
Prevention
There is no specific prevention. General measures include:
- Preventing head injuries.
- Treating and monitoring chronic kidney and hormonal diseases.
- Avoiding kidney-damaging poisons and medicines.
- Regular health checks and tests for older cats.
Important for cat owners
Diabetes insipidus is rare but serious in cats, requiring careful investigation and lifelong monitoring. Remember that persistent thirst and excessive urination are always reasons to take your cat to a vet promptly. Only timely diagnosis and appropriate treatment help preserve quality of life and prevent serious complications.
Monitoring duration depends on the cause and response. Even treatment expected to be long term should not be stopped without veterinary assessment when symptoms temporarily improve.
This article provides general information and does not replace veterinary care. Contact a vet if you notice signs of illness in your cat.
Frequently asked questions
Can I remove water from a cat drinking a lot?
No. Drinking replaces water lost in urine, and restriction can cause dangerous dehydration. Increased thirst needs veterinary investigation.
Is diabetes insipidus the same as diabetes mellitus?
No. Diabetes insipidus involves ADH or the kidneys' response to it. Diabetes mellitus involves insulin function and glucose regulation, so treatments differ.
Is clear urine enough for diagnosis?
No. Concentration is measured in a sample and compared with blood tests and other findings. Several other conditions also cause dilute urine.
Can a young cat have diabetes insipidus?
Yes. Central disease has been described in young cats, for example after head injury. Age alone neither confirms nor excludes it.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Diabetes Insipidus in Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Disorders of the Pituitary Gland in Cats, Merck Veterinary Manual, accessed 2026-11-03.
- Diabetes Insipidus in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Central diabetes insipidus in five cats: Clinical presentation, diagnosis and oral desmopressin therapy, Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- Is my cat drinking and weeing too much?, PDSA, accessed 2026-11-03.
- Testing for Increased Thirst and Urination, VCA Animal Hospitals, accessed 2026-11-03.
- Initial Triage and Resuscitation of Small Animal Emergency Patients, Merck Veterinary Manual, accessed 2026-11-03.
- 2026 iCatCare consensus guidelines on the diagnosis and management of chronic kidney disease in cats, Journal of Feline Medicine and Surgery, accessed 2026-11-03.