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Diabetes In Cats

Diabetes Mellitus in Cats

Feline diabetes is on the upswing and has become a hot research topic over the past few years. These recent studies are changing the way we treat diabetic cats.

Diabetes is an inherited disease but it often will not ever develop if a cat is maintained at a healthy weight. The more obese a cat becomes the more likely it will become diabetic. The risk is highest in middle-aged cats 8-12 years old and males are affected twice as often as females. Free choice feeding increases the risk and diets high in carbohydrates, especially grains like wheat and corn, are also a factor. Cats with large abdominal fat deposits (big bellies) are more likely to become diabetic than cats with their fat more evenly distributed.

The best prevention and most important treatment for feline diabetes is to feed your cat a prescription diet made for diabetes management at an amount that will maintain a normal, lean body weight. The dry versions of these diets contain about 15% carbohydrate and the canned versions only 5%, because more carbs are needed to create a dry food that holds together and doesn’t get rancid. Cats already overweight will usually lose weight on these diets, so both the weight loss and the diet itself are important. For cats that won’t eat canned food, the dry versions will do but canned is preferred.

There are two forms of diabetes in cats: diabetes insipidus and diabetes mellitus. Diabetes insipidus is a very rare disorder that results in failure to regulate body water content. Your cat has the more common type of diabetes, diabetes mellitus. Simply put, diabetes mellitus is a failure of the pancreas to regulate blood sugar.

The pancreas is a small but vital organ that is located near the stomach. It has two significant populations of cells. One group of cells produces the enzymes necessary for proper digestion. The other group, called beta cells, produces the hormone called insulin.

Types of Diabetes

In cats, two types of diabetes mellitus have been discovered.  Both types are similar in that there is a failure to regulate blood sugar, but the basic mechanisms of disease differ somewhat between the two groups. 

1.  Type I, or Insulin Dependent Diabetes Mellitus (IDDM), results from total or near-complete destruction of the beta cells.  As the name implies, cats with this type of diabetes require insulin injections to control their blood sugar.  Chronic pancreatitis, or inflammation of the pancreas, can damage or destroy the beta cells.

2.  Type II, or Non-Insulin Dependent Diabetes Mellitus (NIDDM), is different because some insulin-producing cells remain.  However, the amount produced is insufficient, there is a delayed response in secreting it, and the tissues of the cats body are relatively resistant to it. 

Diet and Diabetes

Both types of diabetes may go into remission with a change in diet and weight loss. Unless the cat is on another prescription diet for a medical problem, such as food allergies, the first step in treatment of a diabetic cat is to change them over to a diabetes diet. Cats eating only canned diabetes diets and nothing else do not need insulin the majority of the time.

These diets are ultra-low in carbohydrate amount. The idea is the less carbohydrate in the diet, the less insulin is needed, so the small amount of insulin produced by diabetic cats will be enough to keep their blood sugar under control.

Some cats absolutely refuse to eat canned foods. Since dry diabetes diets are higher in carbohydrates than the canned versions, dry food doesn’t work as well as canned to keep blood sugar under control.

About 1/3 of cats who would need insulin on a regular cat food do not need it when on a dry prescription diabetes diet – canned food works much better but dry diabetes diets are still much more effective than regular over-the-counter cat food. On a dry diabetic cat diet, about 1/3 of  cats won’t need insulin. Those eating a dry diabetes diet who do still need insulin usually need on average only 1/3 the dose they would need eating a regular cat food.

There are two prescription diets made for diabetic cats, one by Purina and the other by Hill’s. These diets work on the principle that cats are very good at making glycogen from muscle protein and their bodies can then use glycogen for fuel instead of glucose. This reduces the amount of insulin their bodies need and also prevents a blood sugar spike after eating.  On a low carbohydrate diet the cat does not have to process a large amount of sugar at one time, so the blood sugar level stays more constant. 

When cats refuse to eat these diets, things become more challenging. Most cats who will not eat a therapeutic diabetes diet will need insulin injections. There are some over-the-counter canned cat foods with low carbohydrate levels but OTC diets are not as tightly controlled as Rx diets. Ingredients and carb levels can vary from flavor to flavor ot batch to batch. It’s difficult to get consistent blood glucose control with a non-prescription diet.

What about oral medication for diabetes control?

When diet change and weight loss are not sufficient, diabetic cats may be treated with an oral drug called glipizide. This drug stimulates the remaining functional Beta cells in the pancreas to produce or release more insulin.  Alternatively, they may be treated with insulin.  Many cats are easier to give injections to than oral medications.

Glipizide is a human medication. Studies show that 72% of cats whose blood sugar stays high despite weight loss and diet change will respond to Glipizide and their blood sugars will come down. Glipizide works more slowly than insulin and can cause kidney and liver problems that will need to monitored for. It also should not be used in cats with ketosis.

What if diet change, weight loss and/or Glipizide doesn’t work?

 If we do need to start insulin injections, there are several types. Glargine insulin is better at putting cats into remission than the older PZI insulin. However, some cats do better on PZI. We usually start with Glargine and switch to PZI if we are not happy with how the cat is doing. Glargine insulin has gotten very expensive, so we may also choose to use PZI insulin due to cost.

Cats with NIDDM may ultimately progress to total beta cell destruction and then require insulin injections. On the other hand, cats are the only species that can regenerate beta cells. Some cats will go from being diabetic to non-diabetic because the pancreas generates new cells to produce insulin. Cats can switch very rapidly from needing a lot of insulin to needing none, or vice versa.

Careful monitoring is needed for the cat’s entire life because if insulin is given to a cat that doesn’t need it any more, or doesn’t need as much, insulin shock occurs, which can quickly be fatal. High blood sugar causes slow deterioration and eventually death. Low blood sugar can cause death in just a few hours. If we can manage a cat with diet and weight management and no insulin that’s ideal, because we don’t need to worry about insulin dosages.

This is not to say that the prognosis is dim or hopeless for cats needing insulin. On the contrary, diabetic cats can live for many years with proper care. Giving insulin and monitoring blood sugar levels is definitely a commitment though.

What Insulin does for the Body

The role of insulin is much like that of a gatekeeper.  It stands at the surface of body cells and opens the door, allowing glucose to leave the blood stream and pass into the cells.  Glucose is a vital substance that provides much of the energy needed for life, and it must work inside the cells.  Without an adequate amount of insulin, glucose is unable to get into the cells.  It accumulates in the blood, setting in motion a series of events that can ultimately prove fatal.

When insulin is deficient, the cells become starved for a source of energy.  In response to this, the body starts breaking down stores of fat and protein to use as alternative energy sources.  As a consequence, the cat eats more; thus, we have weight loss in a cat with a ravenous appetite.  The body tries to eliminate the excess glucose by eliminating it in the urine.  However, glucose (blood sugar) attracts water; thus, urine glucose takes with it large quantities of the body’s fluids, resulting in the production of a large amount of urine.  To avoid dehydration, the cat drinks more and more water.  Thus, we have the four classical signs of diabetes:  


Weight loss

Ravenous appetite

Increased water consumption

Increased urination

Diagnosing Diabetes

The diagnosis of diabetes mellitus is based on three criteria: the four classical clinical signs, the presence of a persistently high level of glucose in the blood stream, and the presence of glucose in the urine. 

The normal level of glucose in the blood is 80-120 mg/dl.  It may rise to 250-300 mg/dl following a meal or when the cat is very excited.  However, diabetes is the only common disease that will cause the blood glucose level to rise above 400 mg/dl.  Some diabetic cats will have a glucose level as high as 800 mg/dl, although most will be in the range of 400-600 mg/dl.

To keep the body from losing its needed glucose, the kidneys do not allow glucose to be filtered out of the blood stream until an excessive level is reached.  This means that cats with a normal blood glucose level will not have glucose in the urine.  Diabetic cats, however, have excessive amounts of glucose in the blood, so it will be present in the urine.

The diagnosis of diabetes seems rather simple, and in most cats it is.  However, some diabetic cats do not meet all the criteria.  For these, we check fructosamine levels.  The fructosamine level represents the average blood glucose level over the past two weeks.  It minimizes the influence that stress and eating have on blood glucose levels and can be very helpful in understanding difficult cases.

Initial Care for Sick Diabetic Cats

Blood glucose cannot be normalized without treatment  Treatment almost always requires some dietary changes.  Whether an individual cat will require oral therapy or insulin injections will vary.  As for the owner, there are two implications: financial commitment and personal commitment. 

The financial commitment can be significant during the initial regulation process usually reaches at least $500 and may be much higher. 

If your cat is seriously ill he or she may be hospitalized for a few days initially, to deal with the immediate crisis and to begin the regulation process.  The “immediate crisis” is only great if your cat is so sick that it has quit eating and drinking for several days. Cats in this state, called ketoacidosis, may require a week or more of hospitalization with quite a bit of laboratory testing. This may be done here but often ends up being done at an emergency clinic with 24 hour care.  Hopefully we have caught the disease long before this stage.

The financial commitment may be significant if complications arise.  We will work with you to achieve consistent regulation, but some cats are difficult to keep regulated. 

Just a note about ketoacidosis; When animals cannot utilize glucose they start to break down protein to use as fuel. One of the products of protein breakdown is ketone. Ketone is a toxin that makes animals ill. Protein breakdown also changes the pH of the blood, making it more acidic. This also causes illness. The combination of these two things is called ketoacidosis.

The kidneys try to get rid of the ketones via the urine, so we diagnose ketoacidosis by testing urine as well as blood. Treatment for ketoacidosis includes fluid administration, supportive care and insulin, which may be given in with IV fluids.

Giving Insulin

If your cat needs insulin, your personal commitment to treating your cat is very important in maintaining regulation and preventing crises.  Most diabetic cats require insulin injections twice daily, at about 12-hour intervals.  They must be fed the same food in the same amount on the same schedule every day.  If you are out of town, your cat must receive proper treatment while you are gone.  These factors should be considered carefully before deciding to treat a diabetic cat who needs insulin.

There is more than one type of insulin, and some cats do better on one than another – we find this out through a process of trial and error. It is important that you pay close attention to our instructions related to administration of medication, to diet, and to home monitoring.  Consistency is the key to prolonged regulation.  The more you keep the medication, diet, and activity the same from one day to the next, the easier it will be to keep your cat regulated.

When your cat is well regulated, the maintenance costs are reasonable.  Insulin can be costly, but the vials will usually last 3-6 months.  We will also need to recheck your cat’s blood sugar level every few months, either by spot checking or application of a glucose sensor, to make sure the insulin dose does not need to be adjusted.

The most serious complication that can arise from insulin injections is hypoglycemia or low blood sugar; if severe, it may be fatal.  This may occur due to inconsistencies in treatment, poor appetite from some other health problem or because some cats can have a spontaneous remission of their disease.  You should always have Karo syrup and an oral syringe handy to give your cat sugar if needed. A hypoglycemic episode may require an emergency trip to the vet.

Symptoms of low blood sugar include weakness, drunken appearance with stumbling and poor balance, confusion or staring into space, coma, vomiting, seizures and eventually death. These signs are most likely to occur at the time of nadir, when blood sugar is at its lowest. This is usually around noon or midnight, though it can happen at any time.

If your cat just looks a little wobbly, give 3 ml of Karo syrup orally every 10 minutes and wait to see if he perks up. Feed some canned food or regular dry cat food once he is able to eat. If signs are more severe, such as seizures, give Karo and head to a clinic fo IV glucose and monitoring. You can come here to Best Friends during the day, but at night or on weekends you will need to go to Lakeshore or WVRC. If your cat is unconscious or seizuring, go to the closest emergency clinic! Usually we prefer that you go to Lakeshore but time is of the essence for this.

How Soon Will My Cat Feel Better?

It takes time for the metabolism to change in response to the change to a diabetes diet. In mild cases, we may just give it some time for the food to work, without starting insulin. In cases where the cat is ill or glucose levels are very high, we will usually start on insulin and then taper off of it as the body changes in response to the new diet.

Most cats with diabetes suffer from diabetic neuropathy. This painful condition is caused by the build-up of sorbitol deposits on the nerves. Sorbitol is a sugar produced in diabetic pets that the body doesn’t utilize well. In dogs it is deposited in the eyes, which is why most diabetic dogs become blind eventually. In cats it is nerve function that is affected, at least until the blood sugars come down and the diabetes is under control. We recommend pain medication, usually gabapentin, for most newly diagnosed diabetic cats to keep them more comfortable, even those without significant lameness.

Cats with diabetic neuropathy usually develop an odd, crouching gait and have difficulty jumping up but they can have milder nerve pain that doesn’t cause clinical lameness. (Human diabetics can suffer from this as well and report pain and tingling in their feet.)  

Monitoring Blood Glucose Levels

Blood for testing can be obtained in several ways. Here in the hospital we will often draw blood from a vein to test. Some clients doing long term monitoring at home use a little meter and prick the ear with a stylet to get a drop of blood for testing. If your cat is easy going this works well.

The best way to test, especially when we are initially stabilizing a cat and starting insulin injections, is with a sensor patch called a Freestyle Libre. It’s a plastic disc about 1” in diameter with a small needle at the center. The patch is placed and glued to the skin so the tiny needle penetrates the skin. The little sensor obtains blood sugar readings every few minutes. You read the glucose numbers with a meter we provide or with an app you can download onto an iPhone, version 7 or higher, or a newer Android phone. We can get continuous blood sugar readings for up to two weeks with a single patch.

Patches come in a pack of two and are obtained from a human pharmacy. Bring the patches to us and we will place them on your cat. Be aware that cats can sometimes get the patches off, by rolling on carpeting, rubbing against something or scratching at it. It can be frustrating to spend the money for a patch that is supposed to last two weeks and it’s off in two days. We often dress cats in onesies or sweaters so they can’t rub the sensor off so easily.

Another test we do for diabetes monitoring is called a fructosamine level. A blood glucose reading gives us a value at a single moment in time – what is the blood sugar right now. Fructosamine levels give us an idea of what the average blood sugar has been over the past two weeks or so. Longer tests are being developed for humans and may eventually be available for cats. Right now, we use fructosamine for long term monitoring.

Insulin dosage is adjusted according to blood sugar readings and fructosamine readings in combination. We usually start cats with just one unit of insulin twice a day. Then we increase the dose slowly, making adjustments every few days, until we are happy we have the correct insulin and the correct dose for the particular cat. We do many glucose readings over the course of the day at first. Long term, we usually want readings to be done in the middle of the day, at the blood glucose nadir – the low point for the day. Since low blood glucose is more dangerous than high glucose, it’s the low point we want to look at the most. Pets on insulin are not going to be as tightly controlled as humans. We are happy if the nadir number is around 100-150 and the high point of the day, around the time the insulin is given, can be 200-250 or so.

 Long Term Maintenance

Once a cat’s blood glucose is regulated and stable, we check at least every 3 months long term. This can be a spot test at home with a meter, another Freestyle Libre patch or a panel of tests here at the clinic. We usually want a fructosamine level, a urinalysis, a blood pressure and a chemistry panel twice a year, with just blood glucose readings in between. This will vary depending on how the cat is doing.

We monitor diabetic cats for urinary tract infections by checking urine twice a year. Our laboratory has a nice diabetic cat panel of tests that is reasonably priced. It includes a chemistry panel, including blood glucose; complete blood count (CBC); fructosamine level and urinalysis.

The key to successful diabetes treatment is consistency. 

Your cat needs consistent administration of medication, consistent feeding, and a stable, stress-free lifestyle if possible.  Changes in diet and exercise cause fluctuations in blood sugar levels and the amount of insulin required. To best achieve this, it is preferred that your cat lives indoors.  Although that is not essential, indoor living removes many uncontrollable variables that can disrupt regulation.

If your cat is overweight,  you may notice weight loss on diabetes diets. This is because these foods are high in protein. Cats feel full and stop eating when they have consumed their protein requirement for the day. With a high protein diet they feel full faster and thus usually eat less. Weight loss also helps reduce their insulin needs, so these foods are good all the way around.  As mentioned earlier in this handout, these diets usually reduce or eliminate the need for insulin. No brands of food that you can purchase at a grocery or pet store will do this as well, so it is extremely important to feed only the prescription diet you buy from us. If your cat refuses to eat the prescription products we have a list of OTC foods that are close but this is a compromise that doesn’t always work.

Your cat’s feeding routine is also important.  The average cat prefers to eat about 10-15 times per day, one mouthful at a time.  This means that food is left in the bowl at all times for free choice feeding.  This is the best way to feed a diabetic cat eating dry food but does not work well for canned.  You will also need to monitor how much food is eaten each day.  If you have more than one cat, this may be difficult, but please make an effort, as this is part of the home monitoring that should occur. If a cat is not eating well his insulin requirements will change. A cat that gets a full dose of insulin but is not eating will usually have a dangerous drop in blood sugar, possibly leading to diabetic shock.

Tell Me More About Oral Glucose Control Medication

Insulin injections are usually the first choice because this approach is to replace the hormone that is missing or made in inadequate amounts.  Oral medication, called Glipizide, takes longer to adequately control blood sugar, but over time it can work well for many cats.  Although may people are initially uncomfortable with the thought of giving injections, for most cats, insulin injections are easier than giving tablets.

There is no reliable, practical test to know if your cat’s diabetes will respond well to Glipizide.  Therefore, if we choose to try it, we will place your cat on an initial dose of glipizide for about 1 week.  This is usually done at home if your cat is eating well.  Weekly blood glucose levels are checked for about one month until it is determined whether or not response is occurring.   If response occurs and blood sugar declines the treatment is continued.

We cannot use the Glipizide tablets if:

1)  Your cat does not take tablets well. 

2)  Your cat has been ketoacidotic. (Type II diabetics who can take Glipizide rarely become ketoacidotic.) 

3)  Your cat does better with injections than pills. (Most cats are in this category.  This is not because pills are hard to give but because injections are very easy to give.)

Many people are initially fearful of giving insulin injections.  If this is your initial reaction, consider these points. 

1)  Insulin does not cause pain when it is injected. 

2)  The injections are made with very tiny needles that your cat hardly feels. 

3)  The injections are given just under the skin in areas in which it is almost impossible to cause damage to any vital organ.  Please do not decide whether to treat your cat with insulin until we have demonstrated the injection technique.  You will be pleasantly surprised at how easy it is.

Insulin Therapy and Administration

Insulin comes in an airtight bottle that is labeled with the insulin type and the concentration.  Before using, mix the contents.  It says on the label to roll it gently, not shake it.  The reason for this is to prevent foam formation, which will make accurate measuring difficult, and to prevent the insulin molecules from being damaged by shaking too vigorously.  Some of the types of insulin used in cats settle out of suspension in a few hours.  If it is not shaken properly, it will not mix well, and dosing will not be accurate.  Therefore, the trick is to rock it back and forth or roll it between your palms to mix it without creating foam.  Since bubbles can be removed (as described later), it is more important to mix it well than to worry too much about foam formation. 

Insulin is a hormone that will lose its effectiveness if exposed to direct sunlight or high temperatures.  It should be kept in the refrigerator, but it should not be frozen.  It is not ruined if left out of the refrigerator for a day or two as long as it is not exposed to direct sunlight. However, we do not advise this.  Insulin is safe as long as it is used as directed, but it should be kept out of reach of children.

Several types of insulin are used in cats.  Insulins we have used for years in cats were human products, most of which have been taken off the market over the last few years in favor of synthetic insulins that do not work well in cats.  Veterinary products called Vetsulin and PZI are made for dogs and cats, and most do well on it.  If not, the more expensive but longer lasting Glargine insulin, made for humans under the name Lantis, can be obtained from any human pharmacy.  Vetsulin and PZI have a concentration of 40 units of active insulin crystals per milliliter of fluid.  Thus it is called U40 insulin.  Insulins made for humans have a concentration of 100 units per milliliter and are called U100 insulins.

This is important to know because there are two types of insulin syringes, U40 syringes and U100 syringes.  They are made to be used with their respective types of insulin and must not be interchanged or improper dosing will occur.

Glargine insulin works more slowly than Vetsulin or PZI. It takes longer to establish the correct dose and we generally do a glucose curve after the cat has been getting the insulin for about two weeks instead of within a week or so of beginning treatment. Glargine comes in a bottle and in a pen. It’s usually less expensive per cc to buy the bottle and it lasts longer. You might want to get a pen to start with, until we make sure your cat is doing well on it. The label says the bottle is only good for a month but we are standardly using it for four months with no problems.

Drawing up Insulin

Have the syringe and needle, insulin bottle, and cat ready.  Then, follow these steps:

1)  Remove the guard from the needle, and draw back the plunger to the appropriate dose level.

2)  Carefully insert the needle into the insulin bottle. 

3)  Inject air into the bottle; this prevents a vacuum from forming within the bottle. 

4)  Withdraw the correct amount of insulin into the syringe.

Before injecting your cat with the insulin, verify that there are no air bubbles in the syringe.  If you get an air bubble, draw twice as much insulin into the syringe as you need.  Then withdraw the needle from the insulin bottle and tap the barrel of the syringe with your finger to make the air bubble rise to the nozzle of the syringe.  Gently and slowly expel the air bubble by moving the plunger upward.

When this has been done, check that you have the correct amount of insulin in the syringe.  The correct dose of insulin can be assured if you measure from the needle end, or “0” on the syringe barrel, to the end of the plunger nearest the needle.

Injecting Insulin

The steps to follow for injecting insulin are:

1)  Hold the syringe in your right hand (switch hands if you are left-handed).

2)  Have someone hold your cat while you pick up a fold of skin from somewhere along your cat’s back with your free hand (pick up a different spot each day).

3)  Quickly push the very sharp, very thin needle through your cat’s skin.  This should be easy and painless.  However, take care to push the needle through only one layer of skin and not into your finger or through two layers of skin.  The latter will result in injecting the insulin onto your cat’s hair coat or onto the floor.  The needle should be directed parallel to the backbone or angled slightly downward.

4)  To inject the insulin, place your thumb on the plunger and push it all the way into the syringe barrel.

5)  Withdraw the needle from your cat’s skin.  Immediately place the needle cap over the needle and discard the needle and syringe.

6)  Stroke your cat to reward it for sitting quietly.

7)  Be aware that some communities have strict rules about disposal of medical waste material so don’t throw the needle/syringe into the trash until you know if this is permissible.  If it is not, we can dispose of them for you.

It is neither necessary nor desirable to swab the skin with alcohol to “sterilize” it.  There are four reasons:

1)  Due to the nature of the thick hair coat and the type of bacteria that live near the skin of cats, brief swabbing with alcohol or any other antiseptic does not really kill all the bacteria. 

2)  Because a small amount of alcohol can be carried through the skin by the needle, it may actually carry bacteria with it into the skin

3)  The sting caused by the alcohol can make your cat dislike the injections. 

4)  If you have accidentally injected the insulin on the surface of the skin, you will not know it.  If you do not use alcohol and the skin or hair is wet following an injection, the injection was not done properly.

Although the above procedures may at first seem complicated and somewhat overwhelming, they will very quickly become second nature.  Your cat will soon learn that once or twice each day it has to sit still for a few minutes.  In most cases, a reward of stroking results in a fully cooperative cat that eventually may not even need to be held.

Long Term Monitoring

Determining the level of glucose in the blood is the most accurate means of monitoring.  This should be done about every 3-4 months if your cat seems to be well regulated.  It should also be done at any time the clinical signs of diabetes are present or if a moderate or high amount of glucose is detected in the urine for two consecutive days.

Timing is important when the blood glucose is determined.  Since eating will elevate the blood sugar for several hours, it is best to test the blood at least 6 hours after eating.

The exact best time to test your cat will be determined based on the glucose curve charted with your cat’s initial regulation period. The best times to test the blood sugar are at the high and low points on the glucose curve – the highest and lowest glucose readings for the day.  The highest reading should occur just before an injection of insulin is given.  The lowest should occur at the time of peak insulin effect.  This is usually 5-8 hours after an insulin injection, and the timing should have been determined during the initial regulation process. 

Once a cat is well regulated on its insulin we will often simply test for the low point by drawing a single blood sample at the time your pet’s blood sugar should be at its lowest. Usually this will be early afternoon, about 5-8 hours after the insulin injection is given in the morning. Again, thie exact time will depend on the results of earlier testing during the initial regulation process.

Your part can be performed in one or both of two ways.  The first way is to monitor your cat for signs of diabetes.  To do this, you need to be constantly aware of your cat’s appetite, weight, water consumption, and urine output.  You should be feeding a constant amount of food each day, which will allow you to be aware of days that your cat does not eat all of it or is unusually hungry after the feeding.  You should weigh your cat at least twice monthly.  It is best to use the same scales each time.  A baby scale works well for this.  If you have several cats that eat together and use the same litter box, monitoring weight is the best because it is specific to this one cat.

If possible, you should develop a way to measure water consumption.  The average 10 pound (4.5 kg) cat should drink no more than 7 1/2 oz. (225 ml) of water per 24 hours.  Since this is highly variable from one cat to another, keeping a record of your cat’s water consumption for a few weeks will allow you to establish what is normal for your cat.  Another way to measure water consumption is based on the number of times it drinks each day.  When properly regulated, it should drink no more than four times per day.  If this is exceeded, you should take steps to make an actual measurement.

Urine output can be measured by determining the amount of litter that is scooped out of the litter box.  This is a little less accurate if you have more than one cat that uses the litter box, but it can still be meaningful.  The best way to measure litter is to use a clumping litter and scoop it into a sealable container.  After a few weeks you will be able to know the normal rate at which the jar fills.  Too rapid filling will indicate that your cat’s urine production has increased.

Any significant change in your cat’s food intake, weight, water intake, or urine output is an indicator that the diabetes is not well controlled.  We should see your cat at that time for blood testing.


Hypoglycemia means low blood sugar.  If it is below 40 mg/dl, it can be life threatening.  Hypoglycemia occurs under three conditions:

1) If the insulin dose is too high.  Although most cats will require the same dose of insulin for long periods of time, it is possible for the cat’s insulin requirements to change.  However, the most common causes for change are a reduction in food intake and an increase in exercise or activity.  The reason for feeding before the insulin injection is so you can know when the appetite changes.  If your cat does not eat, skip that dose of insulin.  If only half of the food is eaten just give a half dose of insulin.  Always remember that in the short term  it is better for the blood sugar to be too high than too low.

2) If too much insulin is given.  This can occur because the insulin was not properly measured in the syringe or because two doses were given.  You may forget that you gave it and repeat it, or two people in the family may each give a dose.  A chart to record insulin administration will help to prevent the cat being treated twice.

3) If your cat has a spontaneous remission of the diabetes.  This is a poorly understood phenomenon, but it definitely occurs in many diabetic cats.  They can be diabetic and on treatment for many months, then suddenly no longer be diabetic.  Since this is not predictable and happens quite suddenly, a hypoglycemic crisis (“insulin shock”) is usually the first indication. 

The most likely time that a cat will become hypoglycemic is the time of peak insulin effect (5-8 hours after an insulin injection).  When the blood glucose is only mildly low, the cat will be very tired and unresponsive.  You may call it and get no response.  Within a few hours, the blood glucose will rise, and your cat will return to normal.  Since many cats sleep a lot during the day, this important sign is easily missed.  Watch for it; it is the first sign of impending problems.  If you see it, please bring in your cat for blood testing.

If your cat seems lethargic and hypoglycemia is possible, you should give it Karo or other corn syrup (1 tablespoon by mouth) or feed one packet of a semi-moist cat food.  If there is no response in 15 minutes, contact us immediately for further instructions.  (Note: Diabetic cats should not be fed semi-moist or dry foods except for this situation.) The insulin dosage may have to be adjusted to prevent further hypoglycemic episodes.

If severe hypoglycemia occurs, a cat will have seizures or lose consciousness.  This is an emergency that can only be reversed with intravenous administration of glucose.  If it occurs during office hours, come in immediately.  If it occurs at night or on the weekend, call our emergency phone number, WVRC or Lakeshore Veterinary Specialists and Emergency Center for instructions.

Spontaneous Remission

This is a poorly understood phenomenon that only happens in a few cats.  Unfortunately, it can happen rather suddenly, so a hypoglycemic crisis may be created when the normal amount of insulin is given.  When it occurs, the cat may be normal for a few weeks or for many months.  However, diabetes will almost always return.  Therefore, you should watch for the typical signs of diabetes then contact us for insulin instructions. We usually recommend continueing the special diabetes prescription diet to help reduce the chance for recurrence of the disease.