INSULIN ADMINISTRATION IN THE CAT
BEGINNERS INSULIN ADMINISTRATION GUIDE FOR CATS
Insulin is the injectable medication you will be using to control your diabetic cat’s blood sugar. The goal is maintaining blood sugar levels in an acceptable range over the course of the day with once or twice a day dosing (usually twice.) Keeping the sugars in the proper range will control the excessive urination and appetite that your cat suffers from and it will require some trial and error experimentation to get the correct dose. A dose will be selected based on what research has shown to be a good starting point, and after a couple of weeks your cat will return for a glucose “curve” where blood sugar levels will be mapped out over the course of a 10-24 hour period. The curve will show if the insulin is lasting long enough and if the dose should be raised, lowered, or kept the same. Alternatively, you can learn how to monitor your cat’s blood glucose levels yourself (click here for more information) but if you are a beginner you may want to master giving the injections before moving on to actually taking blood samples.
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). There are presently four insulins commonly in use for cats: Vetsulin (also marketed as “Caninsulin®” in other countries), PZI insulin (presently available as Prozinc® insulin), Lantus® insulin (also called Glargine insulin), and Humulin (genetically engineered human insulin available in several formulations with different duration of action).
It is normal for a small white layer to settle in the bottle after it has been sitting. This layer must be evenly mixed into the solution before drawing up the dose. The manufacturer of Vetsulin recommends shaking the bottle to mix but other manufacturers prefer simply inverting the bottle gently or rolling it in one's palms so as to prevent the formation of bubbles.
BE SURE YOU UNDERSTAND THE DOSE OF INSULIN YOU ARE TO USE.
The bottle you are currently using need not be refrigerated though if you have a supply of insulin bottles, it is probably best to refrigerate the bottles that are not in use.
There are two types of insulin syringes: U-40 (for insulin of the 40 units per cc concentration) and U-100 syringes (for insulin of the 100 units per cc concentration). The type of syringes used must match the insulin used. Most human insulins (Lantus® and Humulin®) are 100 units per cc while most veterinary insulins (PZI and Vetsulin) are more dilute at 40 units per cc.
Insulin syringes may be available through your veterinarian’s office or through your regular drugstore but do not be surprised if a prescription is needed from your drugstore. Insulin purchased at the drugstore may or may not require prescription. Insulin is considered an over-the-counter medication for humans but when it is used in pets, it is technically “off-label” so prescription may be needed.
(original graphic by marvistavet.com)
There are many insulin products available in pens for human use but only two products commonly used in pets: the Vetsulin VetPen and the Lantus Solostar. The Vetsulin VetPen is designed for pet use and all the benefits of the injection pen can be realized. The pen injects its insulin via a push-button mechanism which does not require as much manual dexterity as a syringe. There is also a dosing dial that allows for very accurate measurements. The pen is loaded with a cartridge which lasts several uses while a new needle tip is placed for each use. The needle tip is inserted through the pet's skin and the button is pressed. The needle should stay in place under the skin for a few moments (the manufacturer recommends counting to 5) so that all the insulin dose can be expressed from the pen.
To see a video explaining the process, click here.
The Lantus Solostar is different because it was meant for human use. People require fairly large insulin doses so they go through the Lantus cartridge quickly. A cat will go through a Lantus cartridge so slowly that refrigeration is necessary to get maximum use from the cartridge. The problem is that the Lantus Solostar mechanism will not measure with accuracy if the pen is refrigerated. This means that the pen cannot be used as a pen; it must be used as an unusually shaped vial. Syringes still must be used to draw up the accurate amount of insulin from the pen.
Before actually injecting your pet, practice drawing up the correct amount of insulin
To view a video guide demonstrating how to draw up insulin click here. (The video is made on behalf of Prozinc® insulin, but the procedures are the same for any of the insulin vials.)
Used syringes or pen needles should be placed inside a thick plastic container (such as a liquid laundry detergent bottle or similar receptacle.). If the needle is enclosed such a container, the entire container can be closed up and disposed of in the regular trash at home. Special containers can be purchased for needle disposal or the used syringes can be returned to the veterinary hospital for disposal if you prefer.
HOW TO GIVE THE INJECTIONS
First, feed your cat. A pet that has not eaten a normal meal but receives insulin may drop his or her blood sugar to a dangerous low level. If your cat is not eating, this could indicate a need for a check up with your veterinarian. After the pet has eaten, you are ready to give the injection.
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. The photos here show the injection given straight in the scruff but you actually want to vary the location with subsequent injections: sometimes use the center of the scruff, sometimes use the loose skin towards the sides or over the shoulders. By varying the location, you avoid creating scarring or fat deposits that could interfere with insulin absorption. 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 you are using a pen, simply insert the needle into the skin (be sure the needle is not in fur and is actually through the skin) and press the injection button. Leave the needle in place for a count of five before pulling it out.
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.
Boehringer Ingelheim, the makers of Prozinc insulin, have put together a video on giving insulin to your cat. It can be viewed by clicking here. (Again, these steps would be the same for injecting any insulin.)
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.
Page posted: 1/16/10