Frequently Asked Questions (FAQ)


This section can be used to answer some of the most 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 refer to the main education section to learn more about the concepts discussed.

Table of Contents

    General Questions About Diabetes

   Blood Glucose Levels and Curves

   Hypoglycemia and incorrect injections



Questions And Answers

General Questions About Diabetes

Did I do something to cause the diabetes?
No, not unless you let your pet get 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 the Difference between Type I and Type II diabetes?
Type I diabetes is characterized by destruction of the beta cells (the cells in the pancreas which secrete insulin) with progressive and eventual complete loss of insulin secretion. This type is always insulin dependent. Type II diabetes is characterized by dysfunctional beta cells (irregular insulin production) or the other cells of the body not responding to insulin properly.  Type II diabetes can be insulin dependent or non-insulin dependent. 

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.
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. 
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.

Can other things besides diabetes cause glucose in the urine?

Renal disease can cause glucose in the urine even in a non-diabetic with a 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. It is only recently that animals were treated aggressively for diabetes.  It was not that many years ago that these animals would have automatically been euthanized. 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 cats and dogs?

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 where the blood glucose is measured every 1-2 hours through the day. The patient should be on the same food schedule as at home. For most animals a 10-12 hour curve is adequate but those where 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 feedings 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. See sample bg curves

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 parameter one looks at. Does the insulin lower the blood glucose? When assessing insulin effectiveness one needs to consider the insulin dose as well as the difference between the highest and lowest glucose readings. 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, 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 is may not be valid when the levels are < 80 mg/dl due to the possibility of Somogyi phenomenon that 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 effected by several factors that may make the curve done at the vet's office an inaccurate portrayal of what is occurring at home. Things such as inappetence (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 are 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, probably 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  See also the hypoglycemia page

What should I do if my pet experiences a hypoglycemic event?
If you are home bg testing 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 the bg 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, symptomatic 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 oral mucosa (inside lining of the mouth). This should always be followed with regular food as the action of the syrup is often not long lasting and the hypoglycemia will recur. Therefore, 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 glucoses, 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---for 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 glucoses and lower insulin needs for several days after the hypoglycemic event until the stores are replenished.

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. The reason for this is that if you have no way of knowing how much of an injection you gave and you try to replace what you thing you missed, you could easily misguess and 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 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 if there is any question that some insulin was given, you would want to give a decreased dose (if you are certain only a small fraction was given) or no dose. Always err on the side of safety.

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 is 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's 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 let anyone treat the initial hypoglycemia and send your pet home 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 situation 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 pets will still require a decreased dose such as 25% of normal. This is something to be discussed with the vet. 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 will definitely eat 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?

You will hear arguments for and against 30 days from opening. I use a vial until it is empty--usually about 2 months and have had no problems. My vet at the university says there is no need to discard the vial after 30 days as long as the expiration date is OK. Some will say that after 30 days they see a decrease in insulin potency--I have not. I also did other research before coming to my decision since many people have been instructed to discard their insulin at 30 days. I called the manufacturer of my insulin (Nova Nordisk) and was told as long as I kept the insulin in the fridge it was good until the expiration date whether it was unopened or opened and being used. I called the vet pharmacy at the university and the vet pharmacist stated the 30 day rule was a myth years ago, and recent studies have shown that it was not true---both from a sterility and a potency point of view. She said for home use, the insulin was good until the expiration date even if opened and at room temperature. For hospital use the current policy is 30 days and the reason for that is patient cross contamination and multiple user error which does not occur in the home environment. She also stated a possible reason some people might be see changes in potency may be coincidence or if there were errors being made in the way people remove insulin from the vial (i.e. not mixing well, etc) then these errors would compound daily and just get worse over time making it seem as though they were occurring due to age instead of misuse. I didn't stop there. I spoke with the pharmacy at the university medical center (this one for humans)---who basically repeated the exact same info the vet pharmacy gave me. Hospital policy is 30 days for infection control purposes. Home use is until the vial expiration date, regardless of the vial being open or not. I also verified this with physicians who treat human diabetics.

I also spoke with a friend who has a child with IDDM and she states they use the insulin until the vial is empty which is well over 30 days and have not noticed any need for increased insulin after 1 month or more.

The ADA web site states there may be a slight decrease in potency if used after 30 days, especially if the insulin is stored at room temperature.

So based on all of the above I use a vial until empty but keep it refrigerated and I have had no problems and have noticed no change in potency. But I do understand the possibility whether it be due to age or more likely mistakes in drawing up the insulin which accumulate over time----therefore, when I do change to a new vial, I always do it on at a time where I will be around to monitor effects just in case (i.e. over the weekend in my case).

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 slightly losing potency when compared to refrigerated insulin.  But 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 which 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.

At what dose does once suspect insulin resistance?
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 glucoses 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.

What are the different types of insulin?
Insulin can be differentiated in several ways such as type, source or concentration.

Type: Insulin is available in rapid-, short-, intermediate-, and long-acting forms that may be injected separately or mixed in the same syringe. Lispro is a rapid-acting insulin. Regular is a short-acting insulin. Intermediate-acting insulins include lente and NPH. Insulin preparations with a predetermined proportion of NPH mixed with regular, such as 70% NPH to 30% regular, are considered intermediate acting. The only long-acting insulin is ultralente.

Source/Species: Pork or Human--Insulin is obtained from pork pancreas or is made chemically identical to human insulin by recombinant DNA technology or chemical modification of pork insulin. Beef/Pork insulin is being phased out of production by many companies. PZI is available to veterinarians and can be ordered through them. This is a beef/pork product which some feel works well in cats. Future availability of animal insulin is uncertain, presently both Lilly and Novo Nordisk are producing pork insulin.

Concentration: Insulin is commercially available in concentrations of 100 or 500 U/ml, designated U-100 and U-500 (U-500 is only used in rare cases of insulin resistance in humans). In other countries or when ordering PZI, concentrations of U-40 or U-50 may be used. It is also possible that with animals on very small doses, the insulin may be be further diluted with a special diluent provided by the manufacturer.  But with the new smaller dose syringes, dilution is usually not necessary. Dilution should be avoided whenever possible as errors can arise.

In the United States, U-500 and lispro insulins are the only ones that require a prescription.

Different types and species of insulin have different pharmacological properties, and changing them may affect blood glucose control.  Therefore insulin types should not be changed unless done so for a medical reason.

How should insulin be stored?
Vials of insulin not in use should be refrigerated. Extreme temperatures (below 36 or above 86F;  below 2 or above 30C) and excess agitation should be avoided to prevent loss of potency, clumping, frosting, or precipitation. Specific storage guidelines provided by the manufacturer should be followed. If storing several vials for long-term use, it would be wise to purchase a thermometer that is kept with the insulin and check it frequently to assure the correct temperature range. 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 should not be done. It is not so much that shaking the insulin damages the insulin as much as it produces froth or minute bubbles, many of which you can't even see. Then say you pull up 10 units in the syringe--you don't really have 10 units because you have these minute air bubbles too instead of just insulin. You may also have as result of this froth, an uneven balance of insulin particles to solution and therefore have an even bigger error due to more or less potent insulin in the syringe,  which will also effect 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 of insulins on glycemic control should be assessed by a 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?
Maintenance insulin therapy at home is given as subcutaneous injection, therefore, 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. Some pets are injected on the side, near the shoulder.  The proper areas 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 why you may see 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 hyperglyemia than dogs, but it can occur in dogs too. Glucoses 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. So stress hyperglycemia can be an important factor when determining if a bg reading is a reflection of what the bg is under non-stressed conditions (both at the vet's or at home). 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 bg 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 "Honeymoon" and Transient Diabetes" mean?
Transient diabetes is not a new concept for all our cats out there in diabetes land. It is the proper term for most people to use when their pet intermittently requires no insulin. Most cats who are termed "on a honeymoon" are actually a transient diabetic. Insulin needs will wax and wane in about 20% of diabetic cats. One theory about transient diabetes in cats is that the diabetes is subclinical (you don't see physical signs) until the pancreas is stressed by inflammation, a systemic illness, or an insulin-antagonistic drug (insulin secretion becomes reversibly suppressed). 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 actually a different concept altogether and often gets misused. It is just a popular -- just like all facial tissues get called kleenex. 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 who are always indoors, are not exposed to other animals, or who 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 who 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. 

The information on this page was provided primarily by Brenda. Some information was added later by other contributors.


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Updated October 2000
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