Vetsulin Insulin U-40 for Dogs & Cats, slide 1 of 1

Vetsulin Insulin U-40 for Dogs & Cats

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Vetsulin (porcine insulin zinc suspension) is the only FDA-approved veterinary product for the treatment of diabetes mellitus in both dogs and cats. It's prescribed to help control your pet's glucose levels and alleviate the unpleasant symptoms of diabetes. Vetsulin comes in the form of a sterile, injectable porcine insulin zinc solution, and may help your pet to feel better.

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Vetsulin is indicated for the reduction of elevated blood sugar and associated signs in dogs and cats with diabetes mellitus. Vetsulin is supplied as a sterile injectable porcine insulin zinc suspension.

Possible Side Effects

The most common insulin-related side effect is low blood sugar (hypoglycemia) with symptoms that include; lethargy, staggering gait, seizure or coma. Contact your veterinarian immediately if your pet has a medical problem or side effect from Vetsulin therapy. Other side effects may occur. Talk to your veterinarian about any side effect that seems unusual or bothersome to your pet.

Drug & Food Interactions

Vetsulin can be given with other medications, but your veterinarian may adjust your dose depending on insulin requirements. Progestogen and glucocorticoids should be avoided while taking Vetsulin, as they may counter the effect of insulin. Talk to your veterinarian about any other prescriptions, over the counter medications, vitamins, minerals and herbal products your pet is taking before using Vetsulin.


Seek emergency veterinary medical attention if your pet experiences difficulty breathing, swelling of the lips, tongue, or face, or hives, as these may be a sign of an allergic reaction.

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  1. Prescribing Information

See all items by Vetsulin

  • Item Number
  • Common Brand Name(s)
  • Generic Name
    Porcine Insulin Zinc Suspension
  • For Use With
    Dogs & Cats
  • Administration Form
  • Product Form
  • Health Condition
  • Drug Type
    Insulin, Hormone

Active Ingredients: Purified Porcine Insulin (35% Amorphous And 65% Crystalline) 40 IU, Zinc (As Chloride) 0.08 Mg, Sodium Acetate Trihydrate 1.36 Mg, Sodium Chloride 7.0 Mg, Methylparaben (Preservative), 1.0 Mg.

Recommended Dosage

Use of a syringe other than a U-40 syringe will result in incorrect dosing. Follow dosing instructions exactly as given by your veterinarian. Shake the vial thoroughly to a milky, uniform suspension. Make sure all clumps or particles are completely dissolved, and foam formed during shaking has dispersed, before using. Vetsulin should be given with or right after a meal.

Storage Instructions

Store in an upright position under refrigeration at 36° - 46°F. Do not freeze. Protect from light. Use content within 42 days of the first puncture.


What is Vetsulin?

The first and only insulin approved by the US Food and Drug Administration for treating both canine and feline diabetes mellitus. Vetsulin (porcine insulin zinc suspension) is produced by Merck Animal Health and is available only by prescription.

Is this a brand new insulin?

No, Vetsulin is registered in over 30 other countries as Caninsulin. It was first registered in Australia in 1990, so there is a history of more than 20 years of safety and efficacy with this product.

Is Vetsulin made here in the US?

No, Vetsulin/Caninsulin are manufactured by Merck Animal Health in Germany.

Can Vetsulin be kept at room temperature? Is it okay if Vetsulin is frozen?

Yes, Vetsulin may be kept at room temperature—no higher than 77°F at 60% relative humidity—between dosing administrations. Vetsulin should not be frozen.

What type of insulin is Vetsulin?

Vetsulin is an intermediate-acting, lente insulin containing 40 IU per mL of highly purified porcine insulin. As a lente insulin, Vetsulin is an aqueous suspension containing 35% amorphous and 65% crystalline zinc crystals in a neutral buffer of pH 7.35.

Can Vetsulin be diluted?

No. Vetsulin is a mixture of amorphous (soluble) insulin and crystalline insulin. The crystalline part is relatively insoluble, which is why the insulin activity lasts more than a few hours. Vetsulin has a balance between the amorphous and crystalline parts. If Vetsulin is diluted, the balance between amorphous and crystalline parts is no longer 35% and 65%, relatively speaking. The amount of soluble insulin is increased by the aqueous diluent used. This results in an alteration of the pharmacokinetics of Vetsulin. With a larger aqueous fraction and smaller crystalline fraction, there would be a decrease in the crystalline portion responsible for the second peak of insulin activity.

In addition, the stability of the suspension is unknown if Vetsulin is diluted. The Vetsulin suspension is optimized to maintain the crystalline portion as a salt. If the water content is increased as with dilution, the solution looks for a new balance, ie, it is not stable and the dissolved fraction increases with time.

Can I use 100 IU syringes with Vetsulin?

No, use of a syringe other than a U-40 syringe will result in incorrect dosing. Using a U-100 syringe with Vetsulin would result in an animal receiving 2½ times less insulin than required. Human insulins are formulated at a concentration of 100 IU/mL. If clients use a U-40 syringe with a 100 IU insulin preparation, they would be injecting 2½ times the amount of insulin necessary, which could result in fatal hypoglycemia.

How does Vetsulin differ from human insulin products?

Vetsulin porcine insulin has the same amino acid sequence as natural canine insulin, whereas the commonly prescribed biosynthetic human insulin has a different amino acid sequence. The similar structure may provide more effective regulation of blood glucose and decreases the risk of anti-insulin antibody development in dogs. Unlike the dog, anti-insulin antibodies do not appear to be a problem in cats.

For owners whose dogs or cats have been treated with human insulin, what differences or benefits could they see if their pets were treated with Vetsulin?

Vetsulin facilitates a more optimal treatment protocol than current human insulin products.

Where biosynthetic human insulin is only available in 100 IU/mL concentrations, Vetsulin has a 40 IU/mL concentration allowing for more accurate dosing of small animals and reducing the risk of under- or overdosing. Vetsulin is administered with U-40 syringes or VetPen, making it easier for the client to read and deliver the dose. The duration of activity may be longer.

What issues might a dog or cat encounter when switching from human insulin to Vetsulin?

Caution should be exercised when changing from one insulin product to another. Any change in insulin should be made cautiously and only under a veterinarian’s supervision. Changes in insulin strength, manufacturer, type, species (animal, human), or method of manufacture (rDNA versus animal-source insulin) may result in the need for a change in dosage.

What is diabetes mellitus and what causes it?

Diabetes mellitus is caused by an absolute or relative deficiency of insulin. Animals with an absolute or relative deficiency of insulin are called diabetics.

Insulin deficiency can develop for different reasons:

  • Disorders of the pancreas—the pancreas is unable to secrete enough insulin.

  • Other diseases or the presence of other hormones—may be antagonistic to insulin or cause resistance to insulin. Insulin is unable to function normally in the body.

I have heard about diabetes insipidus; is this the same as diabetes mellitus?

No. Diabetes insipidus, also known as water diabetes, is caused when large amounts of dilute urine are produced. It is a far less common condition than diabetes mellitus. Diabetes insipidus is caused by problems in part of the brain or in the kidneys. There is no glucose present in the urine of animals with diabetes insipidus.

What signs do dogs with diabetes typically show?

The most common signs of diabetes mellitus in dogs are: * Increased drinking * Increased urination * Increased appetite * General signs, such as lethargy and poor coat condition

What do the terms polyuria, polydipsia, and polyphagia mean?

Polyuria is the production of large amounts of urine in a given period (eg, per day). Polydipsia is chronic excessive thirst. Polyphagia is great hunger.

My dog is having problems holding its urine; does that mean it has diabetes?

No, your dog could have a bladder or kidney infection, or some other medical problem. If your dog is having problems holding its urine, you should schedule a trip to your veterinarian as soon as possible.

How is diabetes diagnosed?

Your veterinarian will measure your dog's blood glucose and test your dog's urine for the presence of glucose and ketones. Persistently high blood glucose levels along with glucose in the urine usually mean that your dog has diabetes mellitus.

Are all dogs susceptible to diabetes?

Dogs of all ages can get diabetes. Diabetes most typically occurs in older dogs. Obesity, genetics, and other conditions can contribute to the development of diabetes.

What other problems can be associated with diabetes?

Problems associated with diabetes are generally seen in long-standing cases; they include cataracts in dogs and chronic infections.

What other diseases have the same signs as diabetes?

Dogs with diabetes mellitus drink and urinate a lot. They may also have a good or increased appetite but usually lose rather than gain weight. Other common diseases where some or all of these signs are also seen include: * Cushing's disease (hyperadrenocorticism). * Exocrine pancreatic insufficiency. * Kidney disease To reach a definitive diagnosis of diabetes mellitus, your veterinarian will test your dog's blood glucose levels and for the presence of urine glucose and ketones.

Did I do something to cause diabetes?

No. Diabetes mellitus is due to a lack of insulin produced by the pancreas. It is not caused by a virus or infection. Diabetes in dogs is thought to be an autoimmune disease.

What is the difference between type 1 and type 2 diabetes?

Insulin is produced by the beta cells in the pancreas. Type 1 diabetes is due to the destruction of the beta cells with progressive and eventually complete loss of insulin secretion. This type always requires insulin therapy. Type 2 diabetes is characterized by dysfunctional beta cells (irregular insulin production) or the other cells of the body not responding to insulin properly. Type 2 diabetes may or may not require insulin therapy. In general, all diabetic dogs have type 1 diabetes and require insulin to control their disease. Unlike dogs, cats can fall under the type 1 or type 2 classifications.

What is the expected lifespan for a diabetic dog?

It is only recently that dogs were treated aggressively for diabetes. Sadly, not many years ago these animals would have automatically been euthanized. Today, studies suggest that, if a dog is kept well regulated and does not have any other health problems, he or she should be able to have a normal life expectancy.

Is diabetes in animals similar to that of humans?

Yes, it is very similar. Your dog will be using similar medications, equipment, and monitoring methods as human diabetics use.

Where on my dog's body should Vetsulin be injected?

Injections should be given subcutaneously (under the skin) about 1 to 2 inches below the spine or backbone. Constantly vary the injection location from behind the shoulder blade to just in front of the hip bone, and alternate injections between your pet's left and right sides. Your veterinarian can help guide you as to the recommended locations for injections. Download the Administration Sheet for instructions on how to administer Vetsulin to your dog.

Can I still use a vial of Vetsulin if it freezes?

No, freezing will damage the insulin molecules and reduce the efficacy of the product. If a vial of insulin accidentally freezes in the refrigerator, it should be discarded and a new vial should be used.

Can I still use a vial of Vetsulin if it was forgotten outside the refrigerator between doses?

Ideally, Vetsulin should be stored upright, protected from light, between 35°F and 46°F. Vetsulin should always remain refrigerated. If you accidentally leave a vial out of the refrigerator, contact your veterinarian for instructions.

What else should I know about Vetsulin?

  • Always have a spare vial on hand
  • Protect it from light
  • Keep it refrigerated
  • If it has gotten too hot, or frozen, discard it immediately
  • Discard contents after 42 days of the first vial puncture

What should I do if I think that my dog has very low blood sugar (hypoglycemia)?

If you see any of these signs, try to encourage your dog to eat a small meal or, if this fails, rub some corn syrup on your dog's gums

How much water should I let my dog drink?

If your dog is diabetic and drinking excessive amounts of water, give him/her all it can drink. Your dog's body is trying to combat the high blood glucose level by expelling the excess sugar out of its body through the urine. Once your dog is regulated, this will subside.

What is the importance of making sure my pet is regulated?

If diabetes is left untreated or unregulated, it could cause many complications. These include cataracts, blindness, infections, and in extreme cases, death.

How long does it take to regulate a diabetic animal?

Each case is different. There is no way to put a specific time on it. Sometimes the regulation process will require you to try different dosages, diets, or injection frequencies. Regulation can be achieved sometimes within a month, and in some cases, over a year from the time therapy first started. It is very important to work closely with your veterinarian during this process to avoid further complications. Even after your dog is regulated, frequent veterinarian visits will be necessary to maintain good health.

My dog is ill and not eating. Should I still give him/her an insulin injection?

If your dog is not eating—do not give Vetsulin or any other insulin! If your dog has a reduced appetite, consult your veterinarian on how to proceed with insulin injections.

Should I feed my dog before or after an injection?

It is very important that your dog eats before you administer the injection of Vetsulin. The safest method is to feed your dog first, then give the injection.

What can I give my dog as a treat?

Your veterinarian will be the best person to determine your dog's diet, as he/she best knows its needs. Ask about treats. He/she can probably help you find an appropriate treatment for your dog.

What does the typical diet consist of?

To keep constant from day to day, it is best to use commercially produced rather than homemade foods. Certain high-fiber prescription veterinary diets can be a useful adjunct to Vetsulin therapy. These diets should be avoided in underweight diabetic dogs. If special diets are unavailable, or your dog does not eat the diets, then standard canned dog foods are acceptable.

What is a blood glucose curve?

This is where the blood glucose is measured every 2 hours through the day. The dog should be on the same food schedule as at home. For most dogs, a 10-12 hour curve is adequate but in some instances, 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 of insulin, the frequency of insulin administration, and feeding times may be altered based on these results.

What are some problems with blood glucose curves?

The results of the curve can be affected by several factors that may make the curve done at the veterinarian's office an inaccurate portrayal of what is occurring at home. Things such as inappetence (not eating) and stress (causing hyperglycemia) may occur at the veterinarian's office. Because some dogs refuse to eat at the veterinarian's office, the dog is fed at home first and samples are done until the next scheduled meal. This will give a more representative curve than a dog that has not eaten. In addition, it is not uncommon for curves to vary from day to day because many things can affect 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 6 months, or more frequently if a problem is suspected. Your veterinarian will advise you on the frequency.

What is stress hyperglycemia?

Stress hyperglycemia is caused when the animal is frightened or stressed. It is caused by the release of epinephrine (adrenaline). Glycosuria (glucose in the urine) is usually absent with stress hyperglycemia because the blood glucose does not stay high for a significant period and therefore does not spill into the urine. Stress hyperglycemia does not influence the diagnosis of diabetes because the blood glucose level does not stay elevated long enough to cause glucose to spill into the urine.

Important Safety Information

Vetsulin should not be used in dogs or cats known to have a systemic allergy to pork or pork products. Vetsulin is contraindicated during periods of hypoglycemia. Keep out of reach of children. As with all insulin products, careful patient monitoring for hypoglycemia and hyperglycemia is essential to get and maintain adequate glycemic control and prevent complications. Overdose can result in profound hypoglycemia and death. The safety and effectiveness of Vetsulin in puppies and kittens, breeding, pregnant, and lactating dogs and cats has not been evaluated. See package insert for full information regarding contraindications, warnings, and precautions.

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