Desmopressin will be ineffective in nephrogenic DI which is treated by reversing the underlying cause (if possible) and replacing the free water deficit. The diuretic hydrochlorothiazide (a thiazide diuretic) or indomethacin can be used to create mild hypovolemia which encourages salt and water uptake in proximal tubule and thus improve nephrogenic diabetes insipidus. Amiloride has additional benefit of blocking Na uptake. Thiazide diuretics are sometimes combined with amiloride to prevent hypokalemia. It seems paradoxical to treat an extreme diuresis with a diuretic, and the exact mechanism of action is unknown but the thiazide diuretics will decrease distal convoluted tubule reabsorption of sodium and water, thereby causing diuresis. This decreases plasma volume, thus lowering the glomerular filtration rate and enhancing the absorption of sodium and water in the proximal nephron. Less fluid reaches the distal nephron, so overall fluid conservation is obtained.

Lithium-induced nephrogenic DI may be effectively managed with the administration of amiloride, a potassium-sparing diuretic often used in conjunction with thiazide or loop diuretics. Clinicians have been aware of lithium toxicity for many years, and traditionally have administered thiazide diuretics for lithium-induced polyuria and nephrogenic diabetes insipidus. However, amiloride has recently been shown to be a successful treatment for this condition.

Central DI and gestational DI respond to desmopressin which is given as intranasal or oral tablets. Carbamazepine, an anticonvulsive medication, has also had some success in this type of DI. Also, gestational DI tends to abate on its own four to six weeks following labor, though some women may develop it again in subsequent pregnancies. In dipsogenic DI, desmopressin is not usually an option.

Treatment of hyperglycemia requires elimination of the underlying cause, such as diabetes. Acute hyperglycemia can be treated by direct administration of insulin in most cases. Severe hyperglycemia can be treated with oral hypoglycemic therapy and lifestyle modification.

In diabetes mellitus (by far the most common cause of chronic hyperglycemia), treatment aims at maintaining blood glucose at a level as close to normal as possible, in order to avoid these serious long-term complications. This is done by a combination of proper diet, regular exercise, and insulin or other medication such as metformin, etc.

Those with hyperglycaemia can be treated using sulphonylureas or metformin or both. These drugs help by improving glycaemic control

Dipeptidyl peptidase 4 inhibitor alone or in combination with basal insulin can be used as a treatment for hyperglycemia with patients still in the hospital.

The administration of sodium bicarbonate solution to rapidly improve the acid levels in the blood is controversial. There is little evidence that it improves outcomes beyond standard therapy, and indeed some evidence that while it may improve the acidity of the blood, it may actually worsen acidity inside the body's cells and increase the risk of certain complications. Its use is therefore discouraged, although some guidelines recommend it for extreme acidosis (pH<6.9), and smaller amounts for severe acidosis (pH 6.9–7.0).

Cerebral edema, if associated with coma, often necessitates admission to intensive care, artificial ventilation, and close observation. The administration of fluids is slowed. The ideal treatment of cerebral edema in DKA is not established, but intravenous mannitol and hypertonic saline (3%) are used—as in some other forms of cerebral edema—in an attempt to reduce the swelling.

Food should be offered at the first signs of possible hypoglycemia. If the animal refuses it, a sugar solution (corn syrup, honey, pancake syrup, etc.) should be poured on the finger and rubbed on its gums or under the tongue (sublingually). The solution must be applied this way to prevent possible aspiration of it. Intervet suggests one tablespoon of a sugar solution rubbed onto the gums, regardless of the size of the dog. Another hypoglycemia formula is 1 gram of glucose for every kilogram (2.2 lb) of the animal's body weight. Since sugar acts quickly, a response should be seen within a minute or two.

Honey, syrup, or sugar, as simple carbohydrates, act rapidly and will make the blood glucose rise, but the rise will not last very long, as they are broken down quickly by the body. Feeding something containing complex carbohydrates when the pet is able to eat will make sure another hypoglycemia event does not overtake the rapid rise in blood glucose levels from the sugar solution. Complex carbohydrates take longer to be broken down by the body, so they do not raise blood glucose levels until some time after being eaten. A small meal should be fed and the animal taken for medical evaluation to determine if further treatment is needed. Treatment of a serious hypoglycemia episode is similar to that of diabetic humans: using glucose or glucagon infusions, depending on severity.

Medications used to treat diabetes do so by lowering blood sugar levels. There are a number of different classes of anti-diabetic medications. Some are available by mouth, such as metformin, while others are only available by injection such as GLP-1 agonists. Type 1 diabetes can only be treated with insulin, typically with a combination of regular and NPH insulin, or synthetic insulin analogs.

Metformin is generally recommended as a first line treatment for type 2 diabetes, as there is good evidence that it decreases mortality. It works by decreasing the liver's production of glucose. Several other groups of drugs, mostly given by mouth, may also decrease blood sugar in type II DM. These include agents that increase insulin release, agents that decrease absorption of sugar from the intestines, and agents that make the body more sensitive to insulin. When insulin is used in type 2 diabetes, a long-acting formulation is usually added initially, while continuing oral medications. Doses of insulin are then increased to effect.

Since cardiovascular disease is a serious complication associated with diabetes, some have recommended blood pressure levels below 130/80 mmHg. However, evidence supports less than or equal to somewhere between 140/90 mmHg to 160/100 mmHg; the only additional benefit found for blood pressure targets beneath this range was an isolated decrease in stroke risk, and this was accompanied by an increased risk of other serious adverse events. A 2016 review found potential harm to treating lower than 140 mmHg. Among medications that lower blood pressure, angiotensin converting enzyme inhibitors (ACEIs) improve outcomes in those with DM while the similar medications angiotensin receptor blockers (ARBs) do not. Aspirin is also recommended for people with cardiovascular problems, however routine use of aspirin has not been found to improve outcomes in uncomplicated diabetes.

The general form of this treatment is an intermediate-acting basal insulin with a regimen of food and insulin every 12 hours, with the insulin injection following the meal. The most commonly used intermediate-acting insulins are NPH, also referred to as isophane, or Caninsulin, also known as Vetsulin, a porcine Lente insulin. While the normal diabetes routine is timed feedings with insulin shots following the meals, dogs unwilling to adhere to this pattern can still attain satisfactory regulation. Most dogs do not require basal/bolus insulin injections; treatment protocol regarding consistency in the diet's calories and composition along with the established feeding and injection times is generally a suitable match for the chosen intermediate-acting insulin.

With Lantus and protamine zinc insulin (PZI) being unreliable in dogs, they are rarely used to treat canine diabetes. Bovine insulin has been used as treatment for some dogs, particularly in the UK. Pfizer Animal Health discontinued of all three types of its veterinary Insuvet bovine insulins in late 2010 and suggested patients be transitioned to Caninsulin. The original owner of the insulin brand, Schering-Plough Animal Health, contracted Wockhardt UK to produce them. Wockhardt UK has produced both bovine and porcine insulins for the human pharmaceutical market for some time.

Injections of insulin—either via subcutaneous injection or insulin pump— are necessary for those living with type 1 diabetes because it cannot be treated by diet and exercise alone. Insulin dosage is adjusted taking into account food intake, blood glucose levels and physical activity.

Untreated type 1 diabetes can commonly lead to diabetic ketoacidosis which is a diabetic coma which can be fatal if untreated. Diabetic ketoacidosis can cause cerebral edema (accumulation of liquid in the brain). This is a life-threatening issue and children are at a higher risk for cerebral edema than adults, causing ketoacidosis to be the most common cause of death in pediatric diabetes.

Treatment of diabetes focuses on lowering blood sugar or glucose (BG) to the near normal range, approximately 80–140 mg/dl (4.4–7.8 mmol/L). The ultimate goal of normalizing BG is to avoid long-term complications that affect the nervous system (e.g. peripheral neuropathy leading to pain and/or loss of feeling in the extremities), and the cardiovascular system (e.g. heart attacks, vision loss). This level of control over a prolonged period of time can be varied by a target HbA level of less than 7.5%.

There are four main types of insulin: rapid acting insulin, short-acting insulin, intermediate-acting insulin, and long-acting insulin. The rapid acting insulin is used as a bolus dosage. The action onsets in 15 minutes with peak actions in 30 to 90 minutes. Short acting insulin action onsets within 30 minutes with the peak action around 2 to 4 hours. Intermediate acting insulin action onsets within one to two hours with peak action of four to 10 hours. Long-acting insulin is usually given once per day. The action onset is roughly 1 to 2 hours with a sustained action of up to 24 hours. Some insulins are biosynthetic products produced using genetic recombination techniques; formerly, cattle or pig insulins were used, and even sometimes insulin from fish.

People with type 1 diabetes always need to use insulin, but treatment can lead to low BG (hypoglycemia), i.e. BG less than 70 mg/dl (3.9 mmol/l). Hypoglycemia is a very common occurrence in people with diabetes, usually the result of a mismatch in the balance among insulin, food and physical activity. Symptoms include excess sweating, excessive hunger, fainting, fatigue, lightheadedness and shakiness. Mild cases are self-treated by eating or drinking something high in sugar. Severe cases can lead to unconsciousness and are treated with intravenous glucose or injections with glucagon. Continuous glucose monitors can alert patients to the presence of dangerously high or low blood sugar levels, but technical issues have limited the effect these devices have had on clinical practice.

As of 2016 an artificial pancreas looks promising with safety issues still being studied.

Potassium replacement is often required as the metabolic problems are corrected. It is generally replaced at a rate 10 mEq per hour as long as there is adequate urinary output.

A low-carbohydrate diet, exercise, and medications is useful in type 1 DM. There are camps for children to teach them how and when to use or monitor their insulin without parental help. As psychological stress may have a negative effect on diabetes, a number of measures have been recommended including: exercising, taking up a new hobby, or joining a charity among others.

About 80% of all LADA patients initially misdiagnosed with type 2 (and who have GAD antibodies) will become insulin-dependent within 3 to 15 years (according to differing LADA sources).

The treatment for Type 1 diabetes/LADA is exogenous insulin to control glucose levels, prevent further destruction of residual beta cells, reduce the possibility of diabetic complications, and prevent death from diabetic ketoacidosis (DKA). Although LADA may appear to initially respond to similar treatment (lifestyle and medications) as type 2 diabetes, it will not halt or slow the progression of beta cell destruction, and people with LADA will eventually become insulin-dependent. People with LADA have insulin resistance similar to long-term type 1 diabetes; some studies showed that people with LADA have less insulin resistance, compared with those with type 2 diabetes; however, others have not found a difference.

People with diabetes can benefit from education about the disease and treatment, good nutrition to achieve a normal body weight, and exercise, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications are recommended to control blood pressure.

There is no single dietary pattern that is best for all people with diabetes. For overweight people with type 2 diabetes, any diet that the person will adhere to and achieve weight loss on is effective.

Treatment of HHS begins with reestablishing tissue perfusion using intravenous fluids. People with HHS can be dehydrated by 8 to 12 liters. Attempts to correct this usually take place over 24 hours with initial rates of normal saline often in the range of 1 L/h for the first few hours or until the condition stabilizes.

Chronic hyperglycemia due to any cause can eventually cause blood vessel damage and the microvascular complications of diabetes. The principal treatment goals for people with MODY — keeping the blood sugars as close to normal as possible ("good glycemic control"), while minimizing other vascular risk factors — are the same for all known forms of diabetes.

The tools for management are similar for all forms of diabetes: blood testing, changes in diet, physical exercise, oral hypoglycemic agents, and insulin injections. In many cases these goals can be achieved more easily with MODY than with ordinary types 1 and 2 diabetes. Some people with MODY may require insulin injections to achieve the same glycemic control that another person may attain with careful eating or an oral medication.

When oral hypoglycemic agents are used in MODY, the sulfonylureas remain the oral medication of first resort. When compared to patients with type 2 diabetes, MODY patients are often more sensitive to sulphonylureas, such that a lower dose should be used to initiate treatment to avoid hypoglycaemia. Patients with MODY less often suffer from obesity and insulin resistance than those with ordinary type 2 diabetes (for whom insulin sensitizers like metformin or the thiazolidinediones are often preferred over the sulfonylureas).

Persons with nephrogenic diabetes insipidus will need to consume enough fluids to equal the amount of urine produced. Any underlying cause such as high blood calcium must be corrected to treat NDI. The first line of treatment is hydrochlorothiazide and amiloride. Consider a low-salt and low-protein diet.

Thiazide is used in treatment because diabetes insipidus causes the excretion of more water than sodium (i.e. dilute urine). This condition results in a net concentrating effect on the serum (increasing its osmolarity). This high serum osmolarity stimulates excessive thirst in an attempt to dilute the serum back to normal and provide free water for excreting the excess serum solutes. However, since the patient is unable to concentrate urine to excrete the excess solutes, the resulting urine fails to decrease serum osmolarity and the cycle repeats itself, hence excessive urination. Thiazide diuretics allow increased excretion of Na+ and water, thereby reducing the serum osmolarity and eliminating volume excess. Basically, thiazides allow increased solute excretion in the urine, breaking the polydipsia-polyuria cycle.

There are no known ways of preventing LADA type 1 diabetes, though some researchers believe it could be stopped at a very early stage if a diagnosis is made prior to the body's destruction of its beta cells.

In some forms of MODY, standard treatment is appropriate, though exceptions occur:

- In MODY2, oral agents are relatively ineffective and insulin is unnecessary.

- In MODY1 and MODY3, insulin may be more effective than drugs to increase insulin sensitivity.

- Sulfonylureas are effective in the K channel forms of neonatal-onset diabetes. The mouse model of MODY diabetes suggested that the reduced clearance of sulfonylureas stands behind their therapeutic success in human MODY patients, but Urbanova et al. found that human MODY patients respond differently to the mouse model and that there was no consistent decrease in the clearance of sulfonylureas in randomly selected HNF1A-MODY and HNF4A-MODY patients.

Weight loss and dietary modification are effective first-line lifestyle modification treatments for hypertriglyceridemia. For people with mildly or moderately high levels of triglycerides lifestyle changes including weight loss and dietary modification are recommended. This may include restriction of carbohydrates (specifically fructose) and fat in the diet. Medications are recommended in those with high levels of triglycerides that are not corrected with the aforementioned lifestyle modifications, with fibrates being recommended first.

The decision to treat hypertriglyceridemia with medication depends on the levels and on the presence of other risk factors for cardiovascular disease. Very high levels that would increase the risk of pancreatitis is treated with a drug from the fibrate class. Niacin and omega-3 fatty acids as well as drugs from the statin class may be used in conjunction, with statins being the main medication for moderate hypertriglyceridemia when reduction of cardiovascular risk is required.

How to manage SIADH depends on whether symptoms are present, the severity of the hyponatremia, and the duration. Management of SIADH includes:

- Removing the underlying cause when possible.

- Mild and asymptomatic hyponatremia is treated with adequate solute intake (including salt and protein) and fluid restriction starting at 500 ml per day of water with adjustments based on serum sodium levels. Long-term fluid restriction of 1,200–1,800 mL/day may maintain the person in a symptom free state.

- Moderate and symptomatic hyponatremia is treated by raising the serum sodium level by 0.5 to 1 mmol per liter per hour for a total of 8 mmol per liter during the first day with the use of furosemide and replacing sodium and potassium losses with 0.9% saline.

- For people with severe symptoms (severe confusion, convulsions, or coma) hypertonic saline (3%) 1–2 ml/kg IV in 3–4 h should be given.

- Drugs

- Demeclocycline can be used in chronic situations when fluid restrictions are difficult to maintain; demeclocycline is the most potent inhibitor of Vasopressin (ADH/AVP) action. However, demeclocycline has a 2–3 day delay in onset with extensive side effect profile, including skin photosensitivity, and nephrotoxicity.

- Urea: oral daily ingestion has shown favorable long-term results with protective effects in myelinosis and brain damage. Limitations noted to be undesirable taste and is contraindicated in people with cirrhosis to avoid initiation or potentiation of hepatic encephalopathy.

- Conivaptan – an antagonist of both V and V vasopressin receptors.

- Tolvaptan – an antagonist of the V vasopressin receptor.

Raising the serum sodium concentration too rapidly may cause central pontine myelinolysis. Avoid correction by more than 12 mEq/L/day. Initial treatment with hypertonic saline may abruptly lead to a rapid dilute diuresis and fall in ADH.

Treatment includes spironolactone, a potassium-sparing diuretic that works by acting as an aldosterone antagonist.

American and European guidelines come to different conclusions regarding the use of medications. In the United States they are recommended in those with SIADH, cirrhosis, or heart failure who fail limiting fluid intact. In Europe they are not generally recommended.

There is tentative evidence that vasopressin receptor antagonists (vaptans), such as conivaptan, may be slightly more effective than fluid restriction in those with high volume or normal volume hyponatremia. They should not be used in people with low volume. Their use in SIADH is unclear.

Demeclocycline, while sometimes used for SIADH, has significant side effects including potential kidney problems and sun sensitivity. In many people it has no benefit while in others it can result in overcorrection and high blood sodium levels.

Daily use of urea by mouth, while not commonly used due to the taste, has tentative evidence in SIADH. It, however, is not available in many areas of the world.

The treatment of hyponatremia depends on the underlying cause. How quickly treatment is required depends on a persons symptoms. Fluids is typically the cornerstone of initial management. In those with severe disease an increase in sodium of about 5 mmol/L over one to four hours is recommended.

Certain medications increase the risk of hyperglycemia, including corticosteroids, octreotide, beta blockers, epinephrine, thiazide diuretics, niacin, pentamidine, protease inhibitors, L-asparaginase, and some antipsychotic agents. The acute administration of stimulants such as amphetamine typically produces hyperglycemia; chronic use, however, produces hypoglycemia. Some of the newer psychotropic medications, such as Zyprexa (Olanzapine) and Cymbalta (Duloxetine), can also cause significant hyperglycemia.

Thiazides are used to treat type 2 diabetes but it also causes severe hyperglycemia.

A number of pharmaceuticals may be used in an attempt to bring the polydipsia under control, including:

- Atypical antipsychotics, such as clozapine, olanzapine and risperidone

- Demeclocycline, a tetracycline antibiotic, which is effective due to the side effect of inducing nephrogenic diabetes insipidus. Demeclocycline is used for cases of psychogenic polydipsia, including those with nocturnal enuresis (bed-wetting). Its mechanism of action involves direct inhibition of vasopressin at the DCTs, thus reducing urine concentration.

There are a number of emerging pharmaceutical treatments for psychogenic polydipsia, although these need further investigation:

- ACE Inhibitors, such as enalapril

- Clonidine, an alpha-2 adrenergic agonist

- Irbesartan, an angiotensin II receptor antagonist

- Propranolol, a sympatholytic beta blocker

- Vasopressin receptor antagonists, such as conivaptan

- Acetazolamide, a carbonic anhydrase inhibitor

Lithium was previously used for treatment of PPD as a direct competitive ADH agonist, but is now generally avoided due to its toxic effects on the thyroid and kidneys.

It is important to note that the majority of psychotropic drugs (and a good many of other classes) can cause dry mouth as a side effect, but this is not to be confused with true polydipsia in which a dangerous drop in serum sodium will be seen.