Insulins for Cats

The Textbook of Veterinary Internal Medicine, Sixth Edition, states:

"Diabetic cats are notoriously unpredictable in their response to exogenous (outside) insulin. No single type of insulin is routinely effective in maintaining control of glycemia, even with twice a day administration.

It is not possible to predict which type of insulin will work best in individual diabetic cats. The initial insulin of choice ultimately is based on the veterinarian's personal preference and experience."

Your veterinarian will determine the best insulin therapy for
your cat through a series of insulin and dose adjustments.

Beef-Pork Insulin (PZI Vet® Insulin)

Made by IDEXX Pharmaceuticals, Inc., Protamine Zinc Insulin (PZI Vet®) is insulin that is made specifically for cats. The protamine and zinc help to slow down the release of the insulin into the body’s tissues and helps to provide a long duration of action. PZI Vet Insulin requires a prescription and is bought from veterinarians.

PZI Vet Insulin is made of 90% beef insulin and 10% pork insulin. Beef insulin is very similar to cat insulin, differing by only one amino acid. Some cats that do not respond to human insulin can experience better control, consistency and flatter blood glucose curves with PZI Vet Insulin.

In appearance, PZI Vet Insulin is a clear liquid with white insulin crystals at the bottom of the vial. When mixed gently and thoroughly, it looks milky. It is typically injected twice a day, with meals. However, if an owner is not able to give two injections a day, the cat may benefit in spite of being given only one injection per day. Blood glucose control may not be optimal at this level, though.

PZI Vet Insulin has a concentration of 40 units insulin per milliliter of fluid (U-40).

CAUTION: U-40 insulin must be injected with red-capped U-40 insulin syringes, whose scale goes up to 40 units. These syringes are specially designed to accurately measure U-40 insulin.


Human Insulin

Despite the name, this insulin does not come from human beings! Its chemical structure is the same as human insulin and it is made in a factory using a chemical process. Human insulin is readily available from local pharmacies, and may require a prescription.

Your veterinarian will recommend a type of human insulin, such as intermediate-acting or long-acting, for your cat.

No one insulin preparation is perfect for every cat. Your veterinarian will determine the best insulin therapy for your pet through a series of insulin and dose adjustments.

* NPH is a type of intermediate acting insulin. It is successful in controlling the diabetes of some cats. In others, however, NPH does not last long enough in the body for good blood glucose control.

* Insulin glargine (Lantus) is a long-lasting insulin whose effect lasts from 10 to 16 hours in most diabetic cats. It is absorbed and metabolized by the body in a manner that is similar to PZI insulin.

Human insulin preparations are usually injected twice a day, with meals. Human insulin preparations have a concentration of 100 units of insulin per milliliter (U-100).

CAUTION: Human insulin must be injected with orange-capped U-100 insulin syringes. Their scale matches the concentration of the human insulin.

Insulin Onset, Peak and Duration

Insulin package labels describe how quickly the insulin starts to work (onset of action), when it reaches the greatest effect (peak) and how long it lasts in the body (duration).

In animals, (and for that matter, in people, too) the response to insulin varies greatly from one individual to the next, so these insulin performance descriptions do not always apply. For example, most insulins have an immediate onset of action in cats and dogs, and the duration of action may be much shorter than the number of hours listed on the insulin label.

Shelf life of insulin

Always follow the storage and handling instructions that come with your insulin.

Human insulin
Bottles of human insulin, either open or unopened, generally last for one month when stored at room temperature (59 to 86°F). A bottle is considered open if its seal has been punctured. If you remove the cap but do not puncture the seal, the bottle is considered unopened.

Many people store their unopened bottles in the refrigerator and keep open bottles at room temperature because they find it uncomfortable to inject cold insulin. If stored in a refrigerator, unopened bottles are good until the expiration date printed on the bottle. Opened bottles that are stored in a refrigerator should be used within one month of being opened.

Do not use bottled human insulin past the expiration date printed on the label. And no matter what the expiration date is, throw out the bottle one month after you open it. To help you keep track, write the date that you opened the bottle on the bottle's label.

PZI Insulin
PZI insulin is a more stable solution than human insulins. IDEXX Pharmaceuticals has shelf life data for up to 2 months.

Caninsulin - Cure for Feline Diabetes Part 2

Maintenance
Once the maintenance dose has been established and the animal is
stabilised a long-term management programme needs to be implemented. The aim should be to manage the animal in such a way as to minimise the variations in its insulin requirement. This includes monitoring to detect under or overdose of insulin and adjustment of dose if required. Careful stabilisation and tight monitoring and control during maintenance will help to limit the chronic problems associated with diabetes including cataracts, fatty liver etc.

Various approaches to maintenance have been described. The most clinically rational approach is for the owner to monitor and record the dog's general health (including well being, thirst and appetite) and check urine glucose at least daily. The veterinary surgeon checks the case every 2-4 months (or more often if there are problems) including its health and urine glucose record. Blood glucose is also measured at this time.
The veterinary surgeon based on full analysis of the clinical data and the blood glucose measurement makes adjustments to the insulin dose.

The ability for owners to recognise the signs of hypo- or hyperglycaemia and respond appropriately is important if control is to be achieved during maintenance therapy. Polyuria, polydipsia and polyphagia in combination with weight loss, general bad condition, loss of hair or abnormal furry coat and lethargy are the most common clinical signs of hyperglycaemia and requires administration of insulin to restore blood glucose concentrations to the normal range.

Contra-indications, warnings etc

1. Caninsulin is an intermediate duration insulin and is not intended for the treatment of animals with severe acute diabetes presenting in a ketoacidotic state. Caninsulin must not be administered by the intravenous route.

2. The use of progestogens in animals suffering from diabetes mellitus should be avoided. Ovariohysterectomy may have to be considered.

3. Stress and irregular exercise must be avoided. Care must be taken with the use of corticosteroids.

4. It is important to establish a strict feeding schedule in consultation with the owner that will include a minimum of fluctuations and changes.

5. An adult responsible for the welfare of the animal must carry out administration of Caninsulin.

6. For animal treatment only. Keep out of the reach of children.

Storage
Store refrigerated at 2-8ºC. Protect from light. Store in the upright position. Following withdrawal of the first dose use the product within 28 days. Discard unused material.
Insulin should not be frozen as this will denature the fragile insulin chains. Similarly, high temperatures should be avoided. Before drawing insulin into the syringe, the contents of the bottle should be gently mixed so that they are properly resuspended. Excessive shaking can damage the insulin and thus make the product less effective or even ineffective.

Packaging
Vials containing 10 ml or 2.5 ml in single and multiple packs.

Diabetes Pills for Cats

Oral hypoglycemic agents are pills that lower blood glucose by stimulating the pancreas to produce more insulin or by increasing the cat’s ability to use the insulin that it makes naturally.

About 25% to 50% of cats with a mild form of diabetes may respond well to oral agents. Your cat may respond well to these pills if it has normal or above average body weight, no ketones in the blood or urine, and no underlying disease of the pancreas or other organ.

You play a vital role in your cat’s therapy. You will need to give the pills to your cat as directed, and feed it the diet prescribed by the veterinarian.

There are two types of oral agents for cats with diabetes. Each works in a different way to help manage the cat’s blood glucose. Your veterinarian will determine if any of these medications might be effective for your cat.


Agents that Promote Insulin Release by the Pancreas

Glipizide has been used successfully to treat some diabetic cats. It helps to increase insulin secretion by the pancreas, if the pancreas is still able to produce insulin. This drug also improves insulin sensitivity, so the cat can better use the insulin that it produces naturally.

Glipizide is given twice a day, just before each meal.2

Around 25% to 50% of cats with diabetes respond to glipizide. It may take 3-4 weeks to see if your cat is benefiting from this therapy. The veterinarian may check your cat every one to two weeks for a period of two to three months.

The side effects of glipizide may include vomiting, liver problems, and very rarely, severe low blood glucose (hypoglycemia).

Agents that Block Glucose Absorption

Acarbose belongs to a class of drugs called alpha-glucosidase inhibitors. Acarbose works by slowing down certain enzymes in the intestine so that less glucose is absorbed into the blood. This helps to keep blood glucose from rising very high after meals.

Acarbose has a mild glucose-lowering effect in cats. It is typically used in cats in combination with insulin and dietary changes. The principal side effect – loose stool – occurs mainly at high doses.

Making Pills Easier to Swallow

For maximum effectiveness, oral medications should be swallowed whole. However, if your cat gives you a lot of resistance, here are some approaches you can try:

*Glipizide and acarbose can be crushed if they are administered immediately to the cat. Crush the pill and mix it with a bit of cat food gravy or other tasty liquid. Watch to make sure that your cat licks up all of the mix before giving the cat its regular food.

*Crush the pill onto a piece of paper. Fold the paper and pour the powder into a 3cc irrigation syringe (this type has no needle). Pour a bit of water into the syringe and shake it to mix the pill powder and liquid. Then squirt the mix into your cat’s mouth and hold its mouth closed for a few seconds while stroking its throat to encourage swallowing.

Many cat owners feel that pilling a cat is much harder than giving it an insulin injection. If your cat resists taking pills, talk to your veterinarian about switching to insulin therapy instead.

Special Precautions

If your veterinarian feels that your cat should take oral agents and insulin injections, you will need to be especially careful. A cat on combination therapy has a greater chance of suffering a severe or even fatal low blood glucose reaction (hypoglycemia).

Always have light or dark corn syrup or maple syrup readily available, so that you do not have to search for it if your cat needs it to reverse a low blood glucose.

Diabetes Therapies for Cats

The goal of your cat's diabetes care is to allow it to lead a healthy and happy life. You can do this by:

* Keeping blood glucose levels within an acceptable range (generally, 100 to 300 mg/dL).

* Preventing or delaying diabetes complications such as nerve damage (neuropathy).


In time, with the proper care, anywhere from 10 to 40% of diabetic cats can have their diabetes reversed in the 12 months following diagnosis.1 Most diabetic cats, however, need continuing treatment to control the condition.

Some diabetic cats respond well to oral medications that are used for humans. However, most veterinarians prefer to treat diabetic cats

with insulin from the start. This is because insulin is usually effective in regulating a cat's blood glucose, while pills do not work at all in some diabetic cats.

Oral medications are usually considered if the owner is not able to give insulin injections or if the cat seems to require very small insulin doses, for example, less than one unit, to maintain control. 1

Giving your cat insulin is not that hard. In fact, many cat owners feel that it is easier to give their pet an insulin injection than to give it a pill.