Put this togher at Yahoo. and com and you get a support group for owners of dogs with Diabetes insipidus. From my own experence on a different support list these lists can be a godsend. It may be a dose adjustment may solve your problem – I don’t know – they will…
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Therapy is not mandatory for DI as long as the pet has unlimited access to water, and is kept in an environment where constant urination is not a problem. This usually applies to outdoor pets. Therapy with DDAVP can be administered intermittently, when severe thirst and excess urination is especially undesirable, for example, if guests are visiting. Unrestricted access to water is absolutely imperative.

Follow-up

Optimal treatment for a pet with diabetes insipidus requires both home and professional care, with follow up being critical. Administer prescribed medications and alert your veterinarian if you are experiencing problems treating your pet. Follow up includes:

Periodic rechecks by your veterinarian, especially if the diabetes insipidus is suspected to be caused by a tumor affecting the part of the brain responsible for making ADH.

Seek immediate veterinary care if any illness develops that causes vomiting or causes the pet to reduce his water intake, as there is a risk of life-threatening dehydration if water is withdrawn from pets with DI for even a few hours.

Does your dog have unlimited access to plenty of fresh water? Did the vet do plenty of tests to rule out other illnesses which can also have the same symptoms of DI?

The diagnostic tests recommended will help differentiate DI from these other conditions that can cause excessive thirst and urination:

Diabetes mellitus (excessive sugar in the blood)

Renal glycosuria (excessive sugar in the urine, but not diabetic)

Chronic kidney failure

Pyometra (infection of the uterus)

Hypercalcemia, a condition of excessively high calcium levels in the blood

Liver failure

Hyperadrenocorticism, also called Cushing’s disease, a condition of overactive adrenal glands

Pyelonephritis, an infection of the kidneys

Hypokalemia (low potassium levels in the blood)

Hypoadrenocorticism, also called Addison’s disease, a condition of underactive adrenal glands

Hyperthyroidism (excessive thyroid activity)

Acromegaly (excessive production of growth hormone)

Psychogenic polydipsia (excessive drinking due to psychological reasons, such as a change in the pet’s environment

I’d definitely talk to the vet about other forms of treatment, such as:

Treatment In-depth

Desmopressin acetate (also called DDAVP) is a synthetic form of the hormone ADH. It is the standard therapy for central DI. It comes in two forms: injection and nasal drops. The nasal spray can be transferred to a sterile eye dropper bottle and applied to the eye if the dog won’t tolerate nasal drops. One to four drops administered once or twice a day usually controls the clinical signs. (which you are currently using)

Chlorpropamide may reduce urine output in some dogs, although results can be inconsistent. Severe forms of central DI often don’t respond.

Thiazide diuretics – while it may seem paradoxical to give a dog with DI a diuretic to increase urine output, the net result is usually a reduction in overall urine output.

Salt restriction has a net effect of reducing urine output, and may be used sometimes as the sole therapy for central DI.

Good luck.
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