Pet Diabetes – Frequently Asked Questions

Many diabetic pet owners have frequently asked questions about diabetes management and techniques. Many of the answers are very complete, but some do not provide all the background information. Please check with your Veterinarian prior to administering any medication and if you have more questions.

General Questions About Diabetes

  • Did I do something to cause the diabetes?
  • Is diabetes contagious and can my other pets get it?
  • How is diabetes diagnosed?
  • What the Difference between Type I and Type II diabetes?
  • What is Polyuria, Polypdipsia, Polyphagia?
  • Will the diabetes go away?
  • Can other things, besides diabetes, cause glucose in the urine?
  • What is the expected life span for a diabetic pet?

Blood Glucose Levels and Curves

  • What are the blood glucose goals for dogs and cats?
  • What is a blood glucose curve?
  • How do you interpret the blood glucose curve?
  • What are some problems with blood glucose curves?
  • How often should a blood glucose curve be done?
  • How often should my pet see the vet?

Hypoglycemia and Incorrect Injections

  • What should I do if my pet experiences a hypoglycemic event?
  • If my pet experiences a hypoglycemia event, how much should I decrease the insulin dose?
  • What do I do if I miss all or part of an injection?
  • What should I do if I know I gave too much insulin?
  • What do I do if my pet won’t eat or vomits?
  • When should insulin be given?


  • How long is insulin good for?
  • What happens if I leave the insulin out for several hours by mistake?
  • What is the normal dose of insulin?
  • At what dose does one suspect insulin resistance?
  • How should insulin be stored?
  • How should insulin be mixed and why?
  • Can I use pre-filled syringes?
  • Can I re-use syringes?
  • Where are insulin injections given?
  • How do I get rid of insulin syringes?


  • What is stress hyperglycemia?
  • What is fructosamine?
  • What does “Transient Diabetes” and “Honeymoon Diabetes” mean?
  • Should my pet receive annual vaccinations?
  • How do we prepare for surgery or teeth cleaning?

Questions And Answers

General Questions About Diabetes

Did I do something to cause the diabetes?

No, not unless you let your pet become obese. Obesity is a major risk factor for diabetes.

Is diabetes contagious and can my other pets get it?

Not in the usual sense. Diabetes is not transmitted from one pet to another like a cold or the flu. There is one theory that diabetes may be caused by exposure to an infectious virus which causes damage to the pancreas. So, it is remotely possible, but very unlikely, that both pets were exposed to the same virus, or that one pet transmitted the virus to another pet. But, even then, the virus would have to have the same effect in both pets. If more than one of your pets is diabetic, it is probably just due to chance. If your pets are genetically related, there is a possibility that the diabetes is genetic and that is why it occurred in both pets.

How is diabetes diagnosed?

Diagnosis requires the presence of the clinical symptoms of diabetes (such as polyuria, polydipsia, polyphagia, weight loss) and documentation of the presence of persisting hyperglycemia and glycosuria (glucose in the urine).

What is Polyuria, Polypdipsia, Polyphagia?

  • Polyuria is increased urination.
  • Polydipsa is increased drinking (which occurs secondary to the increased urination).
  • Polyphagia is increased appetite.

Will the diabetes go away?

This is a complicated question that depends on a lot of factors. If the diabetes is the primary disease and it is the result of obesity, the diabetes will most likely improve a great deal, or completely resolve once the pet’s weight is under control. If the diabetes is the primary disease and obesity is not a factor, most likely the diabetes will not go away. But, it can be successfully managed. Some cats experience transient diabetes.

In animals secondary diabetes means that the diabetes is the result of a primary condition. Primary conditions that may result in diabetes include acute pancreatitis, acromegaly, or a tumor of the pancreas. Secondary diabetes can also be the result of a side effect of drugs, such as steroids. If the diabetes is secondary, it might go away after the primary condition is under control.

Can other things besides diabetes cause glucose in the urine?

Renal disease can cause glucose in the urine even in a non-diabetic pet with normal blood glucose levels.

What is the expected life span for a diabetic pet?

Veterinarian research doesn’t have a lot of data on well regulated pets with diabetes. Not that many years ago diabetic animals would have automatically been euthanized. It is only recently that animals have been treated aggressively for diabetes.  The lifespan often quoted in textbooks (2-5 years) include all diabetic pets, including those whose owners do not aggressively manage their diabetic control. Also keep in mind that many are diagnosed later in life, so a 2-5 year life expectancy may not be that different from their average lifespan, anyway. The newer data coming out suggests that, if an animal is kept well-regulated and does not have any other health problems, they should be able to have a normal life expectancy.

Blood Glucose Levels and Curves

What are the blood glucose goals for dogs and cats?

  • Dogs without cataracts: Between 100 mg/dl and 200 mg/dl.
  • Dogs already blind from cataracts: Between 100 mg/dl and 250 mg/dl.
  • Cats: Between 100 mg/dl and 300 mg/dl.

What is a blood glucose curve?

This is a test normally done in the veterinarian’s office where the blood glucose is measured every 1-2 hours through the day. Your pet should be on the same food schedule as at home. For most animals a 10-12 hour curve is adequate. But, those when the insulin duration is greater than 12 hours, a longer curve may be needed.

Insulin effectiveness, glucose nadir (the lowest glucose reading), and duration of insulin effect are the critical parameters one learns from a glucose curve. The dosage or type of insulin, frequency of insulin administration and feeding times may be altered, based on these results. Obtaining only 1 or 2 insulin readings during the day, though commonly done by many vets, is usually not reliable for evaluating the effect of insulin and can lead to erroneous treatment decisions.   

How do you interpret the blood glucose curve?

Insulin effectiveness, glucose nadir (the lowest glucose reading), and duration of insulin effect are the critical parameters one learns from a glucose curve.

The effectiveness of the insulin is the first area reviewed. When assessing insulin effectiveness one needs to consider the insulin dose, as well as the difference between the highest and lowest glucose readings. Does the insulin lower the blood glucose?  A range of 50 mg/dl is OK if the blood glucose range is 125-175 mg/dl, but is unacceptable if the range is 325-375 mg/dl. If the insulin is not effective in lowering the glucose level, it indicates other action needs to be taken. Does the pet need a larger dose? Or is there a reason to suspect insulin resistance and treat that cause?

If the insulin is effective in lowering the glucose level, the next parameter to look at is the lowest glucose value. Ideally, the nadir should be between 100-125 mg/dl. If the nadir is >125 mg/dl, the insulin dose needs to be increased. If the nadir is <100 mg/dl, the dose needs to be decreased. Changes in insulin dosages needs to be re-evaluated in 3-7 days.

Alterations in frequency of injections are generally not made until an acceptable nadir is reached. Once this occurs, assessment of duration is looked at on the glucose curve. Duration of insulin effect may not be valid when the levels are < 80 mg/dl due to the possibility of Somogyi phenomenon, which could falsely decrease the apparent duration. Once the nadir is acceptable, the duration can be more accurately assessed. The duration of insulin effect is roughly defined as the time from injection until the glucose returns to 200-250 mg/dl.

What are some problems with blood glucose curves?

The results of the curve can be affected by factors that may make the curve done at the vet’s office an inaccurate portrayal of what is occurring at home. Things, such as not eating and stress hyperglycemia, may occur at the vet’s. Because some pets refuse to eat at the vet’s the pet is fed at home first and samples aren’t done until the next scheduled meal. This will give a more representative curve than a pet that hasn’t eaten.

Also, it is not uncommon for curves to vary from day to day because many things can effect blood glucose levels, such as appetite, digestion, metabolism, exercise, hormones, stress, etc.

How often should a blood glucose curve be done?

Once regulated, minimally every 3 months, or more frequently if a problem is suspected.

How often should my pet see the vet?

If healthy, most experts recommend every 3 months.

Hypoglycemia and Incorrect Injections

What should I do if my pet experiences a hypoglycemic event?

If you are home and you get a low glucose reading on your meter and your pet is fine, don’t panic. First, ensure that the number was correct:

  • Repeat the sample
  • Was strip filled completely?
  • Was the right function strip code used?
  • Do a system check/calibration, maybe even test on yourself.

If the number truly is low, consider the timing. Is this the time when you would expect your pets blood glucose to be low, or do you expect the number to go lower? Such events as these may be treated with giving normal food or treats and monitoring.

However, hypoglycemic events require more intense treatment. It is important to get the glucose up quickly. Something quickly absorbed should be used, such as corn syrup (Karo syrup), which is applied to the gums and inside lining of the mouth. This should always be followed with regular food, because the action of the syrup is not long lasting and the hypoglycemia will recur. Therefore, after an event close monitoring of the pet is required, even when everything seems OK.

The vet should be alerted of this and, depending on the severity of the symptoms and your ability to monitor blood glucose levels, the pet may need to be seen in the vet clinic for closer monitoring. If the hypoglycemic event is severe, hospitalization and treatment with IV glucose maybe required. Hypoglycemic events severe enough to cause serious symptoms, such as extreme lethargy or seizure, should be cause for admission in most cases. This is because of blood glucose monitoring and the ability to administer IV glucose due to the very high likelihood of recurrent hypoglycemic events after initial treatment. Severe hypoglycemia can result in brain damage or death.

If my pet experiences a hypoglycemia event, how much should I decrease the insulin dose?

Whenever signs of hypoglycemia occur and there have been no causative events, such as decreased eating, excessive exercise or vomiting, the insulin dose needs to be decreased, usually by 10%-25%.

Also, severe hypoglycemia can result in decreased glucose stores in the body and, thus, result in lower glucose levels and lower insulin needs for several days after the hypoglycemic event, until the stores are replenished. Be sure to consult your vet.

What do I do if I miss all or part of an injection?

Under most circumstances the wisest thing is just to wait until the next injection time and continue with your usual routine. Realistically you have no way of knowing how much of an injection was received and you could easily give an overdose, which could lead to hypoglycemia. The resulting hypoglycemia is acutely far more dangerous than the hyperglycemia which may result from a single missed injection. In some pets, extra insulin doses by as little as 1/2 unit can be significant. If you are absolutely sure your pet didn’t receive the insulin you could just give another dose. However always err on the side of safety. BEST ADVICE: Wait til next scheduled injection!!

What should I do if I know I gave too much insulin?

It depends on the individual pet and the amount of the overdose. If it is only a small percentage overdose and the pet’s glucose was higher to begin with, there may not be any serious events as a result. Either the glucose will remain at safe levels, or a slight hypoglycemia may result and can be treated with extra food.

If a significant overdose is given, this is considered a medical emergency and your pet needs to be taken to the vet prior to the onset of any symptoms, i.e. as soon as the mistake is noted. A serious overdose can result in a rapid and drastic drop in glucose, which can result in seizure, brain damage, or death. If you wait until you see symptoms before taking your pet to the vet, it may be too late to prevent these life-threatening effects. The pet will probably be monitored for at least 24-48 hours, as the hypoglycemia can be recurring and quite severe. If you gave a large overdose, don’t  treat the initial hypoglycemia and get your pet to the vet right away. Longer-term monitoring is required.

What do I do if my pet won’t eat or vomits?

The insulin dose needs to be adjusted. A decreased dose needs to be given, but how much of a decrease will depend on the individual pet and is something you need to discuss with your veterinarian ahead of time so that you can be prepared. Usually, a decrease of 25%-50% is given if the pet eats poorly. Even if a pet doesn’t eat at all, usually the pet will still require a decreased dose such as 25% of normal. If the problem of decreased eating continues past 24 hours, your pet needs to be examined by the vet in order to evaluate the source of the problem.

When should insulin be given?

In humans, insulin is usually given 30-60 minutes before the meal. This allows the insulin action to be present at the time the food is being digested. But this is not always safe in animals since, unlike a human, if an animal doesn’t feel like eating, they simply won’t. If this occurs and your pet has been given a full dose of insulin, a dangerous hypoglycemic event could occur. Most vets will, therefore, recommend giving the injection just after the pet has eaten. Some owners who know their pets habits will inject before or during meal. If you do this, it is wise to observe your pet to ensure that the entire meal is eaten. If your pet has a tendency to vomit, you should probably wait 15-30 minutes after meal to assure the food will stay down and be sure a full dose is safe to give.


How long is insulin good for?

There is mixed guidance on this subject. The prescription says 30 days however most vets say as long as the expiration date is OK it can be safely used. There may be a slight decrease in potency if used after 30 days, especially if the insulin is stored at room temperature. For hospital use, the current policy is 30 days and the reason is the potential for cross contamination and multiple user error, which does not occur in the home environment.   

What happens if I leave the insulin out for several hours by mistake?

No problem. Just put it back in the refrigerator. In fact, most insulin can be kept at room temperature all the time (check your package insert), though, it may have an increased risk of losing some potency when compared to refrigerated insulin. However, be sure the insulin was not exposed to heat or direct sunlight for a long time. If it was, you probably want to be safe and start a new vial of insulin.

What is the normal dose of insulin?

In dogs, insulin is usually started at 0.5 Units/kg/per dose and most can be maintained at < 1.1 Units/kg/per dose (not per day). But, there are also animals that are maintained at much higher (or lower) doses, and this is OK as long as there are not any underlying illnesses which are causing it.

When should you suspect your pet is insulin resistant?

Insulin resistance is suspected only after it is required that the animal gets >1.5 U/kg (dog) or >6 U (cat) and all blood glucose levels are >300. Insulin resistance is also suspected when excessive amounts of insulin are required to maintain glucose < 300 (i.e. >2.2 U/kg in the dog). These amounts are PER DOSE, not per day.

How should insulin be stored?

Specific storage guidelines provided by the manufacturer should be followed. If storing several vials for long-term use, a thermometer that is kept with the insulin will help to assure the correct temperature range.  Vials of insulin not in use should be refrigerated. Extreme temperatures (below 36 or above 86°F; below 2°C or above 30°C) should be avoided. In addition avoid excess agitation to avoid loss of potency, clumping, frosting, or precipitation.  Insulin in use may be kept at room temperature (if room temperatures corresponds to manufacturer’s recommendations) to limit local irritation at the injection site, which may occur when cold insulin is used. A slight loss in potency may occur after the bottle has been in use for longer than 30 days, especially if it was stored at room temperature.

How should insulin be mixed and why?

The vial of insulin needs to be mixed to ensure an even dispersion of the insulin suspension. This should be done by gently shaking or rolling the vial between your hands. If the insulin is not well mixed, you are not getting the correct dose of insulin. Incomplete mixing will accumulate over time making the remaining solution in the vial more strong or more weak. Vigorous shaking produces minute bubbles that can affect the dosage or the balance of insulin particles to solution. Therefore, the result is an even bigger error due to more, or less, potent insulin in the syringe, which will also affect the potency of what is left in the vial.

Can I use pre-filled syringes?

Pre-filled syringes are stable for up to 30 days when kept in a refrigerator. If possible, the syringes should be stored in a vertical position, with the needle pointing upward, so that suspended insulin particles do not clog the needle. The pre-filled syringe should be rolled between the hands before administration. The effect of premixing insulins on glycemic control should be assessed based on blood glucose results. When premixing is required, consistency of technique and careful blood glucose monitoring are especially important.

Can I re-use syringes?

Manufacturers of disposable syringes recommend that they be used only once, since the sterility of a reused syringe cannot be guaranteed and the physical condition of the needle may be damaged. However, some people reuse a syringe until its needle becomes dull, bent, or touches any surface other than the skin or insulin vial. Most insulin preparations have bacteriostatic additives that inhibit growth of bacteria commonly found on the skin. Therefore, it may be safe to re-use syringes. The needle must be recapped after each use and should not be cleansed with alcohol, as that can remove the protective coating and make injections more painful. The syringe being reused may be stored at room temperature.

Where are insulin injections given?

Insulin therapy at home is given as subcutaneous injection. The injection can be given anywhere there is adequate subcutaneous tissue and where there is little risk of an intramuscular injection (which will have a more rapid and potent effect) or of hitting bone. The scruff of the neck is usually used, due to the large amount of subcutaneous tissue, ease of injection and lack of pain response. In some pets, this area can have a problem with absorption, so a different area may be chosen. The proper areas for injection will vary with each pet, so have your vet show you the appropriate areas. Different areas will have different absorption rates, so it is important to be consistent in where you give the injection. You should not inject in the scruff one day, then in the hip or flank the next. Unlike an intravenous injection where the substance is injected directly into the blood stream, giving a shot subcutaneously does not guarantee absorption, and that is another reason there may be variations in blood glucose control from one day to the next.

How do I get rid of insulin syringes?

Regulations in some states require the destruction of used insulin syringes and needles. The used syringe should be placed in a puncture-resistant disposal container. Consult your local trash authority for the appropriate disposal method in your area. If you are not allowed to dispose of used syringes in your trash, your vet or pharmacy may dispose of them for you. 


What is stress hyperglycemia?

Stress hyperglycemia is caused when the animal is frightened or stressed. It is caused by the release of epinephrine (adrenaline). Cats are more prone to stress hyperglycemia than dogs, but it can occur in dogs, too. Glucose levels as high as 300-400 mg/dl have been documented in non-diabetic stressed cats. “Stress” is not something which is easily noted—a cat may appear calm, even to the owner, but still be having stress hyperglycemia. Glycosuria (glucose in the urine) is usually absent with stress hyperglycemia because the blood glucose doesn’t stay high for a significant period of time and therefore does not spill into the urine. Stress hyperglycemia does not influence the diagnosis of diabetes because the blood glucose does not stay elevated long enough to cause glucose to spill into the urine.

What is fructosamine?

A type of protein in the blood which can be used to measure glycemic (glucose) control over a longer period of time. For more information see the section on Fructosamine/glycosylated Hemoglobin.

What does “Transient Diabetes” and “Honeymoon Diabetes” mean?

Transient diabetes is not a new concept for diabetic cats. It is the proper term to use when a pet, intermittently, does not require insulin. Most cats that are termed “on a honeymoon” are actually transient diabetics. Insulin needs will wax and wane in about 20% of diabetic cats. One theory about transient diabetes in cats is that you don’t see physical signs until the pancreas is stressed by inflammation, a systemic illness, or an insulin-antagonistic drug. Hyperglycemia itself can also impair insulin secretion. This effect of glucose toxicity is reversible by correcting the hyperglycemic state. So, with insulin given to correct the high glucose state and then, also, the correction of the condition or drug which caused the increased glucose in the first place, the diabetes resolves and the pet does not need insulin. Future requirements for insulin depends on the function of the beta cells and the presence of any other conditions or drugs that may again cause hyperglycemia.

“Honeymoon” is a different concept altogether and often gets misunderstood. Honeymoon is an event which can occur in both cats and dogs, as opposed to transient diabetes, which rarely occurs in dogs. It is called “honeymoon” because it occurs at the beginning of the diabetes diagnosis, usually within the first weeks to months after diagnosis. With honeymoons, there is a temporary reduction in insulin requirement, but rarely a permanent or semi-permanent discontinuation of insulin. This probably has more to do with fluctuations in beta cell function than anything else. In a Type I diabetic, the beta cells usually die off and, hence, the end of the honeymoon.

Should my pet still receive annual vaccinations?

Whether or not to continue annual vaccinations should be discussed with your veterinarian. The possible risks from vaccines, and the stress it may place on the immune system should be measured against the benefits of vaccination. Pets that are always indoors, are not exposed to other animals, or those that are elderly, may be candidates for discontinuing some vaccinations or switching to a longer vaccination schedule (every 2-3 years instead of every year). With pets that are exposed to other animals, the risks of vaccination may be outweighed by the benefits of disease protections. If your pet’s diabetes is uncontrolled, you may want to delay vaccinations until your pet is healthier. Rabies vaccines are usually required by law, but your vet can obtain a waiver from the local authorities if he or she determines your pet is not healthy enough to receive the vaccination or it poses a health risk.

How do we prepare for surgery or teeth cleaning?

Each vet will have their own preference for how they want you to prepare your pet for a surgery or a procedure like teeth cleaning. Since a diabetic pet must have it’s food and insulin in regular amounts and at certain times, you must discuss these factors with your vet when you schedule the procedure. How the vet wants you to prepare your pet will depend on factors such as your pet’s food and insulin schedule, overall health, the procedure being done, and the vet’s personal preferences. You and the vet should schedule the procedure so that it causes the least amount of disruption to your pet’s diabetes management routine. After the procedure, your pet may need extra monitoring to determine if the diabetes is controlled. This may be for just a day or two while your pet recovers from a simple procedure, or for a longer period if the procedure was extensive or if it changed your pet’s overall health status. For example, teeth cleaning may leave the pet’s mouth tender for a day or two and it may not want to eat. So, monitoring for those days is important to be sure the pet does not become hypoglycemic. But, the teeth cleaning may have also eliminated some gum infections, which may result in the pet requiring less insulin for the long term.