Last Updated: 07/05/2025
Learn all about the use of Caninsulin in pets: how it works it's uses side effects and more.
Author: Dr Jacqui Victor BVSc MANZCVS (Medicine of Cats)
Reading Time: 27 minutes - medium read
During digestion, carbohydrates are converted to sugar (glucose) which provides the body's cells with energy. Glucose enters cells with the help of the hormone insulin, which is produced by the pancreas. If there is not enough insulin, glucose stays in the bloodstream and blood sugar levels rise, leading to diabetes mellitus.
Diabetes can usually be treated successfully with insulin injections along with dietary and lifestyle adjustments. Caninsulin is the first insulin licensed for treating diabetes mellitus in both dogs and cats, and is generally the preferred first choice of insulin for dogs. Caninsulin is an intermediate-acting lente insulin containing porcine insulin. Caninsulin works to restore your pet's insulin needs and reduces elevated blood glucose levels, therefore reducing or eliminating the clinical signs of diabetes mellitus including excessive thirst, excessive urination, weight loss and increased appetite.
Caninsulin is administered once or twice daily by subcutaneous injection (under the skin). Your veterinarian will show you how and where to give these injections and advise you on rotating the injection site. Generally, this is done in the areas just behind the shoulder blades to just in front of the hip bone.
Caninsulin may be administered using a U-40 (40 International Units per mL) syringe or via a U-40 reusable insulin injection pen (VetPen).
Syringes
This is the traditional way of administering insulin, using U-40 syringes with Caninsulin multidose vials (available in 2.5mL or 10mL vials). To avoid potentially dangerous dosing errors, do not use any other type of syringe to administer Caninsulin.
Vetpen
A specifically calibrated U-40 reusable insulin injection pen that is used with replaceable Caninsulin cartridges and disposable needles. Many owners find the Vetpen more convenient, and it's also associated with increased dosing accuracy at lower dosages.
Your vet will advise the best timing of meals to coincide with your pet's insulin injection, however:
The onset of action for Caninsulin is usually 30-60 minutes, with its peak effect at around 4 hours in dogs and 4-6 hours in cats. Caninsulin lasts between 14-24 hours in dogs and 8-12 hours in cats.
Many pets start showing signs of improvement as soon as Caninsulin is started, however it can take a few weeks or months to significantly improve or eliminate your pet's symptoms.
The most serious side effect of Caninsulin is hypoglycaemia (low blood sugar) which can be life-threatening if left untreated.
Signs of hypoglycaemia include:
If you notice any of the symptoms of hypoglycaemia, please contact your veterinarian or emergency clinic immediately. Rub some sugar syrup or honey onto your pet's gums, and if they are able to swallow, try feeding some of their food.
Rarely, local injection site reactions may occur, and very rarely, allergic reactions to porcine insulin have been reported.
The use of progestogens (oestrus inhibitors) and glucocorticoids (eg cortisone, prednisolone) should be avoided during Caninsulin treatment. The concurrent administration of oral hypoglycaemic drugs (which lower blood glucose) is not recommended.
Caninsulin should be protected from light and high temperatures - store it upright in the refrigerator between 2 and 8°C. Do not freeze.
Shake the vial thoroughly before use until a uniformly milk suspension is obtained. Use Caninsulin within 28 days of opening the vial.
All syringes and needles should be disposed of immediately in an appropriate sharps/biohazard container.
Your veterinarian will advise the appropriate dose and frequency of Caninsulin for your pet, based on their blood glucose levels and weight. Dosages are tailored to suit each diabetic pet's individual requirements, and your pet's insulin dosage requirements may change over time.
You and your veterinarian will work closely together to ensure you are giving the correct insulin dose every day to reduce your pet's high glucose levels and clinical signs of diabetes, whilst also avoiding periods of low blood glucose (hypoglycaemia).
A missed dose may cause temporary recurrence of diabetic signs (such as increased thirst and urination) but is generally not serious. It is much safer for your pet to experience a brief period of high blood sugar (by missing an insulin dose) rather than the possibility of causing low blood sugar (hypoglycaemia) by giving too much insulin, as this can be life-threatening. We recommend contacting your veterinarian as soon as possible for advice regarding your pet's next dose, however if your pet is eating and acting normal, it is generally recommended to give their usual dose at the next scheduled injection time.
Most diabetic dogs will require Caninsulin life-long. Some diabetic cats may go into remission (where they no longer shows signs of diabetes) and so no longer require insulin after a period of treatment - however this is only under strict guidance by your vet. Never stop any medication unless advised by your pet's treating veterinarian.
An overdose of insulin results in clinical signs of hypoglycaemia, which can be life-threatening. If you suspect you have given your pet too much insulin, contact your veterinarian or emergency clinic immediately. Rub some sugar syrup or honey onto your pet's gums, and if they are able to swallow, try feeding some of their food.
As changes in insulin dose may be required from time to time, ongoing monitoring of your pet's diabetes is very important. Your veterinarian will advise the frequency of check-ups required for your pet. The most common blood tests performed for diabetes monitoring include blood glucose, serum fructosamine (measures the average blood glucose concentration over the past 2 weeks) and blood glucose curves performed over the day in hospital.
Home monitoring is also very important and we recommend recording the following signs:
There are also Pet Diabetes Tracker mobile apps available to make this easier. Make sure to report any abnormalities to your vet as they may decide to get your pet back for a check-up and further testing, which may result in an adjustment of your pet's insulin dose.
Your vet may ask you to test your pet's urine at home regularly (eg once a week) via a dipstick to monitor the levels of glucose and ketones (which are produced when the body burns fat instead of glucose for energy) in the urine. If you are comfortable, your vet may show you how to measure your pet's blood glucose at home several times a day using a glucometer (which only requires a drop of blood). Alternatively, there are continuous glucose monitors available which your vet can attach to your pet that continuously reads glucose levels in the interstitial fluid (ie fluid between cells, rather than in the blood) throughout the day for up to 2 weeks.
Glargine (brand names include 'Lantus' and 'Optisulin') - this is a longer-acting insulin which is often considered as a first choice of insulin in cats due to its associated higher remission rates. This insulin is approved for use in humans, and although not licensed for use in cats it is commonly prescribed "off-label" by veterinarians.
