Diabetes and the treatment for diabetes in the dog and cat

Diabetes and the treatment for diabetes in the dog and cat are interesting and challenging topics. Diabetes mellitus (DM) is a disorder where the body is unable to regulate blood sugar levels. (There is another dissimilar disease called Diabetes Insipitus that is associated with the Pituitary Gland.) Each case seems to be different, and regulating the diabetic dog or cat so that their blood glucose levels are as normal as possible is vitally important. The real problem with a diabetic dog or cat is that even in the presence of sugar (glucose) in the blood stream, something interferes with the entry of that sugar into the body's cells where it is required for the life sustaining energy of those cells. With no sugar in the cells, the cell dies in a very short period of time.

A highly complicated disease entity, diabetes has been classified according to what pathway of energy metabolism has been disrupted. Fortunately with Diabetes mellitus in dogs and cats most cases can be treated successfully with Insulin injections.


Type I...Occurs when very little or no insulin is produced. In these cases, insulin must be administered by injection.

Type II...Very rarely occurs in dogs and cats. In humans this is present when the body is unable to utilize the insulin that is produced properly.

Transient DM...This occurs most often in cats where diabetic signs are variable. Some diabetic cats may even have periods where they no longer need insulin injections. These periods are unpredictable and blood sugar level tests may need to be done routinely and the cat watched closely for signs of reoccurring diabetes.


The most common signs of diabetes are:
  • polyuria (PU) - frequent and more productive urination
  • polydipsia (PD) - increased water intake
  • polyphagia - excessive appetite
  • weight loss
  • lethargy
  • sugar in the urine

Because there is such a buildup of sugar in the blood stream there is the sensation of thirst in the animal and so it drinks more water to "dilute" the blood. PD (polydipsia) is the result... the animal drinks excessive amounts of water. Of course the animal then needs to urinate more often and greater than normal amounts. This increased urination is called PU (polyuria). Weight loss occurs even in the presence of an increased appetite because the carbohydrate consumed cannot be used for energy or stored as fat and because the animal metabolizes its own fat and tissue protein for energy instead of utilizing the dietary carbohydrate. If left untreated, Diabetes Mellitus leads to muscle wasting, depression, vomiting, kidney failure and death. Some dogs develop ocular cataracts quite rapidly and this is another sign that may lead to getting the animal in for an examination by the veterinarian. In cats, often the owner will notice a wobbly gait or weakness in walking or jumping. Muscle wasting and weakness are commonly seen in diabetic cats.

Insulin injections, daily or twice a day, can be a true life saver for dogs and cats with Diabetes Mellitus. There are now special Careful adjustments to the Insulin dose may need to be made diets just for diabetic dogs and cats, too. These are prescription only diets and can play an important role in maintaining the diabetic patient. It is important to note that for optimum blood glucose levels to be maintained the dog or cat needs to have three parameters in balance on a day-to-day basis:
1. The amount and timing of exercise should be the same every day.
2. The amount of food and time of feeding should be the same every day.
3. The amount of Insulin administered should be the same and should be given at the same time each day.

If any one of these three parameters are different on any given day, the requirements of the other two parameters will be changed. For example, if a patient gets the usual amount of exercise today as normal but happens not to eat its meal, then the patient may need considerably less Insulin in that day's injection. Otherwise, if the usual amount of Insulin is given, the pet may become hypoglycemic and develop signs of low blood sugar. Keeping the diabetic pet regulated in the three areas detailed above will enhance the animal's quality of life.

LOW BLOOD SUGAR... Hypoglycemia (Insulin Shock)

If an animal's blood sugar level becomes so low that the energy needs of the cells are not met, the cells begin to suffer and lose their ability to function. Especially true with nerve and muscle cells that have high respiratory rates and that need continuous oxygen and glucose for survival, a lack of glucose results in rapid deterioration of function. The usual signs in a dog that the blood sugar level is too low are trembling, agitation and muscle incoordination. Ultimately a seizure may occur. In cats, salivation muscle tremors and weakness are seen. These animals need a quick source of energy in the form of carbohydrates and will not survive hypoglycemia if oral or intravenous sugars are not administered. Any diabetic dog or cat should be closely monitored for signs of hypoglycemia, especially if the animal vomits or skips a meal and insulin has been administered. The insulin will drive much of the circulating glucose into the cells and if there is no recent dietary source of additional glucose, hypoglycemia may result. As well, if the diabetic animal engages in an unusual session of vigorous physical activity, it may deplete the glucose stores in the body and become hypoglycemic.


NOTE! Each case is different and requires careful individual assessment by a veterinarian. The following presentation is one veterinarian's summary of Insulin Therapy. It is written by a veterinarian who also happens to be a diabetic. Your veterinarian's suggestions and recommendations may vary significantly from this discussion.

Generally start canine patients with NPH insulin at ? unit per pound of body weight twice/day with twice/day feeding. Ideally,Close contact with the veterinarian is important when treating dogs and cats for diabetes. one can generate an insulin response curve with the NPH, but its general action is over the course of twelve hours. Most dogs are hospitalized for two to five days to get their initial diet and insulin dosing regulated, then go home for the owners to feed and treat, with AM and PM blood sugars checked three to four days later. It?s always best to try to regulate a dog on his own home schedule and activity, so frequent blood glucose checking in the early weeks after diagnosis is important. Usually client education on diet and exercise, and problems with treating anxiety (both the owner?s and the dog?s), feeding and dosing schedule can be discussed and accommodated in these first few weeks after the diagnosis of diabetes is made.

Dogs that come in with diabetic ketoacidosis (DKA) are often treated with the fast acting insulins, most often regular but Humalog can also be used. This does require more frequent blood glucose checking (hourly or every 2 hours) to avoid hypoglycemia until stable normal glucose levels are reached and maintained, the dog feels better and accompanying medical concerns are addressed. Other insulins used in canines include Lente (similar action and duration as NPH) and Ultralente (generally about an 18-hour duration insulin). Ultralente has worked successfully as a once per day dose for those owners who prefer to feed only once per day, or for dogs who have always been free-feeders and have food left accessible for them all day.

The most commonly available insulins today are the ?human insulins? made with recombinant DNA processes to more closely resemble the human insulin molecules. Dog insulin is more similar to the pork and beef sources of insulin, which still can be available from pharmacies, but require specific request to obtain them. These beef or pork may be the choice for dogs that seem to require large doses of the ?human insulin? or be exhibiting a resistance or allergy to ?human insulin?.

Follow-up glucose checking on dogs that appear to be doing well is recommended about every two to three months. Some owners have obtained their own glucose meters to more closely follow their dog's blood sugar levels at home. Generally, the complications from diabetes that humans are concerned about such as nephropathy (kidney disease), retinopathy (damage to the back lining of the inside the eye), and nerve disease occur over many years. Most dogs to not have a natural life span long enough to expect these sorts of complications. Cataracts (lens pathology) in dogs subsequent to diabetes is quite common, though, and may need The amount of Insulin needed will be different for each patient. to be surgically removed if vision is impaired.

Experimentation with dogs was essential in the early 20th century for an understanding of what diabetes was and for the discovery of insulin and its purification from the pancreases of slaughtered meat animals for use in treating diabetes. Now, people look forward to advances on the medical horizon such as pancreatic islet cell transplantation, potential growth of pancreatic lslet cells from stem cell research, or assistance from pigs cloned to have cells missing the rejection markers. What this will mean for treatment possibilities in dogs is still unknown.

Keep in mind that any animal that is being treated with Insulin for Diabetes Mellitus should have a restricted lifestyle. That means the patients should get about the same amount of exercise every day, eat about the same amount of feed and at about the same time each day, and then the Insulin dose can be regulated consistently every day. If you change any one of the three variables (exercise, caloric intake, Insulin dose) it has an effect on the other two variables. Consistency in the patient's lifestyle will greatly assist proper dosing of Insulin and result in a happier, healthier pet.