Insulin Administration Guide

STEP ONE: INSULIN AND SYRINGES

Insulin is an over-the-counter medication you will be using to control your diabetic pet’s blood sugar. The goal is once or twice a day dosing (usually twice), maintaining blood sugar levels in the normal range over the course of the day. Insulin is a very simple molecule but it does differ slightly between species (i.e., cat insulin is different from dog insulin which is different from human insulin). In the U.S., most insulins are of human origin, created by genetic engineering for the human market. The usual brand name is “Humulin” and Humulin insulins are available at virtually every corner drug store for approximately $30. They can also be purchased over the internet. Because of their ready availability, your veterinarian may choose one of these products.

Human insulin is modified biochemically by the manufacturer into different types which last for different lengths of time.

Humulin R – fast acting and is similar to insulin secreted by one’s body. This insulin acts too fast and lasts too short a time to be useful in the home setting for pets.

Humulin L or N – intermediate acting.  These are the most commonly used forms of insulin and are usually used twice a day in pets.

Humulin U – long acting insulin but famous for erratic absorption after injection.  It is mostly used for patients who require once a day insulin though there are certainly some animals who must take it twice a day.

There is another type of insulin to consider, and that is PZI which stands for Protamine Zinc Insulin. This long acting insulin was available until the mid-1990’s for human use, and had been met with modest success in feline use. As genetically engineered Human Insulin captured the market, beef insulins such as PZI became unavailable. Demand from feline practitioners, however, prevailed and subsequently Blue Ridge Pharmaceuticals (a division if IDEXX Laboratories) came to reintroduce PZI. The problem with PZI is expense as the company must now make up its costs in achieving a very expensive FDA approval. PZI can be ordered by your veterinarian but you should expect to pay approximately $80 - $100 per bottle (versus approximately $30 per bottle
for Humulin at the local drug store). Obviously, if a cat can be regulated with a less expensive insulin, this would be desirable from a cost perspective; however, it is good to know that PZI is available should it be needed. PZI insulin is currently the first choice for cats according to many internal medicine specialists and many veterinarians prefer to start with it as it is the longest acting product available..

PZI is available through compounding pharmacies but these source do not have lot to lot quality control, meaning the relative strength from batch to batch is not predictable. If one opts for PZI, it is preferable to “bite the bullet” regarding cost and order the reliably manufactured products.

Caninsulin® is a highly purified pork insulin (identical to canine insulin) and is now available in the U.S. as Vetsulin. This product is available through veterinarians, rather than at the corner drugstore, and may come to dominate the market. It is an intermediate acting insulin and is a relitively new product.

Glargine insulin is a product developed for human use with the advantage of being without a “peak.” This means Glargine provides a steady tone of glucose control over most of the day for a diabetic person. Feline use is new and looking promising. For more details click here

Insulin need not be refrigerated.  It is normal for a small white layer to settle in the bottle after it has been sitting.  When getting ready to use the bottle, roll the bottle in your palms to mix in this layer. Do not shake the bottle.

BE SURE YOU UNDERSTAND THE DOSE OF INSULIN YOU ARE TO USE. 
DO NOT ALTER THE DOSE GIVEN ON YOUR OWN.

STORING INSULIN

The following general information concerning storage applies specifically to the Lilly insulin products with the brand names Humulin® (human insulin [rDNA origin]), Humalog® (insulin lispro injection [rDNA origin]), and/or Iletin® (animal source insulin):

  • Do not use any insulin product after the expiration date stamped on the label.
     
  • Do not use any insulin that has been frozen.
     
  • Do not expose any insulin to direct heat or light.
     
  • Before its first use, an unopened vial or cartridge of insulin should be stored in the refrigerator (36o to 46o F [2o to 8o C]) and may be used up to the expiration date stamped on the label. Refrigeration of insulin before first use helps prevent the loss of potency of the product.
     
  • After its first use, a vial of insulin may either be refrigerated (36o to 46o F [2o to 8o C]) or kept at room temperature (below 86o F [30o C]), so long as it is kept away from direct heat or sunlight. Regardless of the storage method, Lilly recommends that a vial of insulin in use be discarded after 4 weeks. Studies evaluating stopper leakage in vials of Humalog, Humulin, and Iletin indicate that the vials have sufficient resealing properties to maintain a good seal after 100 punctures.

SYRINGES

Insulin syringes are made for human use. Humans are notoriously afraid of needles thus the needles are made extra fine so that human diabetics will not feel them.  You will require a prescription from your pharmacy to obtain a box of insulin syringes.

Syringes come in 0.5 cc volumes and 0.3 cc volumes. The syringes are graded in “units.”  The smaller the syringe volume, the easier it will be to read the tiny unit gradations. We recommend the 0.3cc size for cats (although the 05 size is pictured above). If you are using PZI insulin, you will need special “U-40” syringes. These syringes are also marked in “units” but because PZI insulin is made up to 40 units per cc and Humulin is made up to 100 units per cc, PZI units represent a different volume.

When drawing up the insulin, always hold the bottle vertically to avoid unnecessary bubbles in the syringe.  Since insulin is being given under the skin, the presence of bubbles is not an enormous problem (as it would be with an intravenous injection) but we still want to minimize the presence of bubbles. If you get bubbles in the syringe, flick the syringe with your fingers until the bubble rises to the top and then simply push the air out of the syringe with the plunger.

 

 

 

Before actually injecting your pet, practice drawing up the correct amount
of insulin and feel comfortable handling the bottle and the syringes.

To dispose of used syringes it is best to keep a thick plastic container (such as the type liquid laundry detergent comes in) and deposit used needles here.  The container can be closed when it is full and discarded in the regular trash.

GIVING THE SHOTS

Pull up a handful of your pet’s scruff. A triangle of skin is formed. Aim your needle for the center of this triangle and stick the needle in. Do not be shy or the needle will not penetrate the thick skin in this area.  Pull back slightly on the syringe plunger to be sure you do not get blood back in the syringe. If you do see blood, pull the syringe out and start over. If you do not see blood, press the plunger forward and deliver the insulin.

If there is struggling or your pet escapes or for some reason you are not sure if your pet got the entire dose of insulin, DO NOT GIVE MORE. Simply wait until the next scheduled dose.

DIET

Insulin works best in the presence of a high fiber diet.  Ideally this is what your pet should be eating (either dry or canned).  Feed your pet, make sure that a reasonable amount has been eaten, and then give the insulin.  If you think your pet is off food or not eating well, do not give the insulin and notify your vet.

Meals should be approximately equal and fed about 12 hours apart.

 

OPTIONAL OTHER MATERIALS

Ketodiastix are special urine dipsticks made for human diabetics.  They are meant to measure the amount of glucose in the urine and detect the presence of ketones.  You may use these to keep track of your pet’s diabetic progress (a journal is a handy record for your vet to periodically review).

If you begin to detect ketones in the urine, this can be a very bad sign.  If ketones persist three days or more, you should notify your vet.

 

WHEN TO RETURN

Every individual animal will have a different insulin requirement.  The initial dose selected for your pet is basically just a guess. It will take at least a week for your pet to adjust to the new insulin dose and stabilize. After this time, the pet returns to the hospital for a “glucose curve,” a test requiring all day in the hospital. Blood sugars are measured every 1-2 hours to determine how long the insulin is lasting, when its peak activity is occurring etc. From here, we can tell if or how your insulin dose should be changed, if more frequent administration is needed and whether or not a different type of insulin is needed.  A new dose is selected, another week or two goes by for stabilization, and a new curve is performed until regulation is achieved.

WHAT TO WATCH FOR

It is not unusual for a pet’s insulin requirement to change over time.  When this happens you will notice a return in weight loss, excessive appetite, and excessive thirst and urination. This is an indicator that your pet needs a glucose curve to re-adjust the insulin dose.

    INSULIN SHOCK/HYPOGLYCEMIA

    When the insulin dose is too high relative to the pet’s activity or appetite, it is possible for a dangerous level of hypoglycemia to occur. The pet will become groggy, listless, cold, even uncoordinated and drunken.  First aid at home can be life saving.

    • Immediately offer the pet food.
       
    • If the pet will not eat, you will need to give sugar. The easiest way to do this is with light Karo syrup.  Spoon some syrup into the pet’s mouth or you may wish to keep some frozen “ice cubes” of syrup in case of emergency. You may slip an “ice cube” into the pet’s mouth. Swallowing is not necessary as sugars are absorbed directly through the mucous membranes of the mouth. Your pet should revive with this procedure.
       
    • Contact your vet at once as sometimes IV sugar drips are needed for a few hours after such an episode.  Your vet will need to determine what threw your pet out of balance in this way.
       
    • Do not give more insulin until your vet tells you to.  If you are lucky, your pet may no longer be diabetic but this will have to be determined for sure.

SUCCESSFUL MANAGEMENT OF THE DIABETIC DEPENDS ON A GOOD UNDERSTANDING OF THE DISEASE AT HOME. IF YOU HAVE ANY QUESTIONS OR PROBLEMS, BE SURE TO ASK YOUR VETERINARIAN.
 

Page last updated: 9/23/05