Two Flexible Dosing Options for Dogs
Administration information is useful to share with clients and practice staff to ensure the proper amount of insulin is given.
Caninsulin vials and cartridges should be shaken thoroughly until a homogeneous, uniformly milky suspension is obtained1.
To be used with (porcine insulin zinc suspension) 2.5 ml and 10 ml vials.
To be used with Caninsulin 2.7 ml cartridges
In dogs, the initial recommended Caninsulin dose is 0.5 to 1.0 IU/kg, given once or twice daily, as appropriate, following assessment via a blood glucose curve.
Research published on the initial stabilisation phase in dogs using Caninsulin (a lente type insulin) presents an approach to be considered, in conjunction with experience, when making clinical judgements on a case by case basis. This evidence recommends introducing lente-type insulin for diabetic dogs at twice daily dosing2,3,4,5.
During stabilisation dose alterations should not normally be made more frequently than every 3 days and any subsequent adjustment should be made by increasing or decreasing the dose by approximately.
Achieving Effective Glycaemic Control in Dogs
The goals of managing canine diabetes mellitus include:
- Controlling the clinical signs of hyperglycaemia (polyuria, polydipsia, polyphagia and weight-loss)
- Avoiding hypoglycaemia (blood glucose <3.3 mmol/l)
- Achieving a blood glucose concentration of 5.5 -14.0 mmol/l over the course of the day, with a nadir between 5.5-8.5 mmol/l.
- Prevention of the long-term complications associated with diabetes
- Improving quality of life for the diabetic dog
Further adjustments in dosage may be necessary with changes in the dog's diet, body weight, medications, or if the dog develops concurrent infection, inflammation, or other medical disorder.
Hypoglycaemia is a major concern. To help avoid overdosing, particularly during initial stabilisation:
- The dog 's body weight should be rounded down to the nearest whole kilogram
- The calculated dose of insulin should be rounded down to the nearest whole unit
If the duration of Caninsulin on once daily dosing proves to be inadequate, begin twice daily therapy.
If twice-daily treatment is initiated, each of the 2 doses should be 25% less than the once-daily dose of Caninsulin required to attain an acceptable nadir.
For example, a 20 kg dog would receive 10 IU of Caninsulin once daily or 7 IU of Caninsulin administered twice daily. Refer to the Caninsulin data sheet or Summary of Product Characteristics for more information.
How to Give Caninsulin Using a U-40 Insulin Syringe
Use the step-by-step instructions below to teach your clients how to administer Caninsulin to their dog from the comfort of their home.
Downloadable Caninsulin Instructions
Important Dosage Information
Doses of insulin are measured in units: 40 IU/ml insulin contains 40 International Units (IU) per millilitre (ml).
Use Caninsulin with U-40 syringes only to avoid dosing errors when administering Caninsulin to dogs. Human insulin is formulated at a concentration of 100 IU / ml. Using a U-100 syringe, or human insulin pen, with Caninsulin would result in a dog receiving two and a half times more insulin than required, which could result in fatal hypoglycaemia.
Clients may attempt to replenish their syringe inventories and/or insulin supply from their local human pharmacies. Most pharmacists are not aware of Caninsulin, VetPen, or the U-40 syringes, nor do they stock these items. As this potential situation can be fatal, it is strongly advised to educate clients to purchase both Caninsulin and the U-40 syringes from their veterinary practice.
Preparing the Dose
After washing your hands, take the Caninsulin (porcine insulin zinc suspension) vial out of the refrigerator. Shake the vial until the insulin is uniformly milky, allowing any foam to disperse.
- Carefully remove the cap from the needle and insert the needle into the vial
- Turn the vial upside down, making sure the tip of the needle remains inside the liquid in the vial
- Withdraw the correct dose into the U-40 syringe
- Before removing the needle from the vial, check the syringe for any air bubbles
- If bubbles are present, hold the syringe up and tap its side until the bubbles float to the top. Push them out with the plunger and withdraw the correct dose
- Remove the needle from the vial
- The injection should be given under the skin, 2-5 cm (3/4 to 2 inches) from the middle of your dog's back, varying from between the shoulder blades to the middle of the back region and alternating sides
- Gently insert needle in centre of folded skin
- Push plunger until all the insulin is given
- Pull needle out and dispose of syringe into appropriate sharps collector
Refer to the Caninsulin Summary of Product Characteristics for more information.
- The injection site can depend upon what is best for the client and their dog
- Alternate injection site between left and right side for comfort and best results. Repeat injections at the same site can lead to ineffective treatment
Convenient and Accurate Caninsulin Injections
VetPen from MSD Animal Health is the first and only veterinary insulin pen for use in the treatment of diabetes mellitus in dogs and cats. To avoid dosing errors, VetPen must be used with 40 IU/ ml , 2.7 ml Caninsulin cartridges.
VetPen is available in 2 sizes: 8 IU VetPen with dosing increments of 0.5 IU and 16 IU VetPen with dosing increments of 1 IU. Caninsulin (porcine insulin zinc suspension) (2.7 ml) cartridges are available in boxes of 10.
Advise pet owners not to reuse VetPen needles. After a single use, needles should be disposed of in approved sharps or biohazard containers.
How to use Caninsulin VetPen
Watch the video and use the step-by-step instructions below to teach your clients how to use Caninsulin VetPen.
The six simple steps to using VetPen
- Insert cartridge
- Attach needle
- Remove air bubbles*
- Select dose
- Inject dose
- Remove needle
*or priming the cartridge: Only with the first use of cartridge
Step 1: Insert Cartridge
- Wash your hands
- Remove the cap and unscrew the body of the VetPen from the cartridge holder
- Ensure the dose selector arrow points to the start line – if not, press the release button
- Carefully insert the cartridge into the cartridge holder
- Screw the cartridge holder onto the body of the VetPen ensuring you are firm but gentle
Step 2: Attach the Needle
- Carefully remove the paper tab from the outer needle
- Carefully attach the capped needle onto the end of the VetPen by turning it clockwise until tight
- Gently invert the VetPen up and down 10 times – always mix the Caninsulin before each injection to ensure accurate dosing
Step 3: Remove air bubbles - prime the VetPen:
Before the first use, it is important to remove any air from the cartridge (priming) to avoid injecting air and ensure accurate dosing.
- Prepare VetPen over the sink
- Holding the VetPen vertically with the needle pointing up, remove the outer caps from the needle
- Tap the VetPen gently with your finger to push any bubbles to the top
- Dial one unit on the dose selector by turning the dose selector clockwise
- Push the release button, ensuring the dose selector is visible
- Repeat the process until a steady stream of insulin is ejected from the tip of the needle. You may expect to eject as many as six to eight units of air before achieving this
- Hold the VetPen horizontally and check that the cartridge is free of air bubbles. If not, you need to repeat the above process until the cartridge is bubble free. NOTE: the cartridge contains two small glass beads to assist the mixing of insulin – these are not air bubbles
- Ensure the arrow on the VetPen points to the start line on the dose selector
Your VetPen is now ready for use.
Step 4: Setting the dose
- Turn the dose selector clockwise until you reach the prescribed dose
NOTE: if your clients have an unsteady hand or poor eyesight, they can use the release button and dose selector adaptors.
Step 5: Giving the Injection:
- The injection should be given under the skin, around the shoulder blade area with loose skin. Alternate sites with each dose
- Tent the skin (lift a triangle of skin with your thumb and second and third finger) and insert the needle under the skin horizontally. Keep pressing and continue to hold the injection button firmly with your thumb until the dose selector arrow returns to the start line. Then count slowly to five to ensure the dose is completely administered. You can then remove
- Advise your client to be sure to make a fuss of their pet, provide positive reinforcement to make the experience a positive one
Step 6: Removing the needle
- Following the injection, remove the needle by inserting it into the needle remover and unscrewing it
- Press the blue tip on the needle remover to release, and dispose of, the used needle carefully and safely in the sharps container
Changing the cartridge
Advise your clients to always check the number of units left in the cartridge. If there aren’t enough for the dose, they need to change the cartridge.
- Ensure the VetPen needle has been removed to prevent accidental injury
- Unscrew the cartridge holder from the VetPen body and remove the cartridge
- Rewind the internal plunger by holding the white lower part of the VetPen. Turn the VetPen body clockwise until the internal plunger is fully retracted. NOTE: incorrect re-winding of the internal plunger can result in damage to the VetPen
- Return to step 1 to load the new cartridge
Refer to the VetPen video for more information.
Injection Tips for VetPen users
- Advise your clients to always prepare the VetPen away from their pet
- If your client suspect only a partial dose has been given, do not attempt to re-dose. They need to wait and give their dog its usual dose at the next injection time or contact the practice
- If your client over-dial, advise them never wind back the dose selector. Dispose of the insulin in the sink and dial up the correct dose. Dialing back the dose selector may damage the VetPen and result in inaccurate dosing
- If insulin leaks out of the VetPen after injection, check for small air bubbles. Do not attempt to re-dose. If you see a couple of drops of insulin after the injection, this is normal
- Remove the needle after use. Do not re-cap or store the VetPen with the needle attached and never re-use the needle
- The VetPen (loaded with cartridges) should be stored in the fridge, with the cap on
- Discard the cartridges after 28 days of first use
- You can use the VetPen pouch as a carry case when travelling
Changes in Insulin Requirements
Is an Adjustment Needed?
Insulin requirements may change suddenly even after a long period of stability because of any of the following concurrent factors:
- Inflammation or infection (e.g. pyoderma, cystitis)
- Altered exercise regimen
- Weight loss or gain
- Additional medications
- Other illnesses or diseases (e.g. renal failure, heart failure, Cushing's disease, hypothyroidism)
- Changes in progesterone concentrations caused by dioestrus
- Corticosteroid or progestogen administration
Vets should re-evaluate dogs with diabetes at appropriate intervals and adjust the dose based on clinical signs, urinalysis and glucose curve results.
Dose adjustments in the dog should be performed in increments of 10%. Following adjustment, wait to re-evaluate until the new dose has been given for a minimum of 3 days, unless evidence of hypoglycaemia appears.
Aim to maintain blood glucose concentrations below the renal threshold, between 10-12 mmol/l for the majority of dogs, for a substantial part of the day. This will result in the disappearance of most of the dog's clinical signs, which is the main goal of therapy.
Monitoring and Adjusting Dose
Re-evaluate your canine patients a minimum of 3 days after starting Caninsulin (porcine insulin zinc suspension):
- Ask for the owner's overall impression of the dog's progress, especially regarding clinical signs of diabetes
- Re-weigh the dog. Modify the overall dosage of Caninsulin if significant weight gains or losses have occurred
- Develop a blood glucose curve to determine if a satisfactory response to the insulin dose has been achieved
- Dose adjustments based on the glucose curve generally should be performed in increments of 10%. Dose adjustment should be made no more frequently than every 3 days
- If the dog's clinical signs persist and the blood glucose curve indicates a duration of activity of less than 14 to 18 hours, then twice-daily injections at 12-hour intervals may be indicated. When switching from once-daily to twice-daily therapy, the Caninsulin dose needs to be decreased by 25% (not 10%). For example, if a dog receives 20 IU of Caninsulin once daily, the new dose would be 15 IU twice daily
- Once stabilised on Caninsulin, dogs should be rechecked every 2 to 4 months
Changing from once to twice-daily therapy
When switching dosage from once-daily to twice-daily, the Caninsulin dose needs to be decreased by 25%. For example, if a dog receives 20 IU of Caninsulin once daily, the new dose would be 15 IU twice daily.
If ideal stabilisation has not been achieved, it is suggested to first investigate the cause of poor regulation: e.g. owner administration issues, insulin storage issues, use of improper syringes, Somogyi overswing, undiagnosed concurrent conditions.
When clinical signs disappear and the owner is happy with the situation, the main goals of therapy have been achieved.
Refer to the Caninsulin Datasheet for further information.
Tailoring Diets for Healthy Dogs
Good glycaemic control is dependent upon a controlled and consistent dietary intake. The dietary requirements of a dog with diabetes is highly variable – the diet must be tailored to each individual dog, ensuring that food offered is palatable and will be readily eaten6.
Body weight is a major factor
Obese dogs require reduced caloric intake, either through feeding a calorie-restricted diet or by feeding a reduced quantity of the normal diet. Increasing physical activity will also be beneficial in obese dogs. Conversely, underweight dogs may require calorie-rich diets such as pediatric or convalescent diets.
Consider concurrent diseases
It’s important to consider what other diseases and needs your patient might have. It may be that the dietary management for these associated problems is more critical than a specific ‘diabetic’ diet.
Timing of meals
Traditionally, the dog’s daily food intake should be divided into two meals. Meals should be timed so that the absorption of glucose from the gastrointestinal tract coincides with peak action of the administered insulin. This will minimise fluctuations in blood glucose concentrations and thus episodes of hyperglycaemia or hypoglycaemia.
It is important for owners to remember that dietary consistency is critical – both the type and amount of food given, as well as feeding times, should be as similar as possible each day.
Fibre-rich diets have been shown to slow the postprandial glucose surge in dogs, which consequently improves glycaemic control6.
For once-daily insulin injections
Give the first meal (two-thirds of the daily amount) prior to the morning Caninsulin injection. This allows your client to see that their dog is feeling well and eating normally before the insulin is given.
The second meal (the remainder of the daily amount) is usually given about 8-10 hours later.
For twice-daily injections
The first meal (half of the daily amount) is given just before the morning Caninsulin injection. This allows your client to see that their dog is feeling well and eating normally before the insulin is given.
The second meal (the remainder of the daily amount) is usually given about 10-12 hours later, prior to the second Caninsulin injection.
Starting Stabilsation with Caninsulin
Presentation of an uncomplicated dog with diabetes
Types of dogs categorised as uncomplicated:
- Dogs presented to their vet after the owner has noted the appearance of clinical signs and without general deterioration—i.e. no diabetic ketoacidosis (DKA). These cases are not emergencies, although dogs without complications should be treated diligently to try to reduce the possibility of them occurring in the future.
- Dogs that have had initial presentation with DKA but have been treated successfully and are generally stable, without ketonuria.
- Perform a thorough physical examination and weigh and body condition score the dog.
- Conduct laboratory testing including complete blood count, urinalysis (including sediment examination), and serum biochemistry profile.
- If the clinical examination or initial biochemistry screening indicates there could be underlying conditions, rule out hypothyroidism, renal failure, inflammatory bowel disease, pancreatitis, exocrine pancreatic insufficiency, hyperadrenocorticism, , neoplasia or hepatic disease as appropriate.
When health status is known, and diabetes mellitus confirmed:
- Explain thoroughly what diabetes mellitus is, that achieving stabilisation may take time (up to 6 months), and what the implications are for the family. Make sure the dog owner understands the therapy involved, and that the dog should be able to live a happy, healthy life with consistent management. This is crucial, as complete cooperation of the owner is essential to management success.
- Treat existing infections or other medical conditions. Many diseases will affect insulin metabolism.
- Ensure the dog is fed an appropriate, palatable diet.
- Begin therapy with Caninsulin (porcine insulin zinc suspension).
Starting Caninsulin in dogs
Clinically evaluate dosage needed
- Weigh the dog. In the event of a fraction of a kilogram, round the body weight down rather than up. For example, a 12.9-kg dog should be dosed as a 12-kg dog. If the dog is grossly overweight, utilize the optimal body weight for calculating the starting dosage of Caninsulin.
- Caninsulin should be administered once or twice daily, as appropriate, by subcutaneous injection. In dogs, the initial recommended stabilisation dose is 0.5 to 1 IU/kg bodyweight given once daily1.
- Further published research on the initial stabilisation phase in dogs using Caninsulin (a lente type insulin) presents an alternative approach to be considered, in conjunction with experience, when making clinical judgements on a case by case basis. This evidence recommends introducing lente-type insulin for diabetic dogs at twice daily dosing2,6.
Determine the owner-preferred method of administration
Caninsulin is available in two presentations, to enable vets and owners to discuss what might be right for them:
Vetpen is the first and only insulin pen to deliver 40 IU/ml insulin via 2.7 ml cartridges. This method is more accurate that the traditional needle and syringe approach and is easy to use7,8.
Caninsulin is also available in 2.5 ml and 10 ml vials for use with specific 40 IU syringes and needles.
Establish a starting dose
- Begin with once-daily injections, then evaluate.
- Some dog owners may do best by easing into the routine of diabetes management with once-daily injections. This is preferable to having an overwhelmed client who sees euthanasia as the only viable option. After acclimating to the ease of giving injections, the client is more likely to willingly accept twice-daily injections, if needed.
- Remember that hyperglycaemia does not kill dogs; hypoglycaemia can.
- Most dogs (two-thirds) will require twice-daily Caninsulin injections.4
- Keep the dog hospitalised for the day and conduct blood glucose testing to verify that the starting dose does not cause hypoglycaemia.
Topics for patient consultation
- How to administer injections
- How to identify and treat hypoglycaemia
- Parameters to monitor at home
- Preferred diet and frequency of meals
- Exercise recommendations
Discharge dog to owner’s care for one week
This first period allows the dog and owner to become accustomed to the injections and related their concerns and challenges to the clinic team.
At home, ask the owner to:
- Monitor and record water and food consumption.
- Maintain starting dose and frequency of administration for the entire week.
- Watch for signs of hypoglycaemia. If so, they should contact their vet immediately.
Problems with Stabilisation
For cases of poor glycaemic control
Ruling out underlying disorders
- Create a blood glucose curve
- Discuss the daily routine—are injections and meals correctly timed? See Feeding schedule.
- Ask for a breakdown of exactly what the dog eats—perhaps the dog is receiving too many treats or an inappropriate diet. See Tailoring Diets for Healthy Dogs section for more information.
Ruling out storage and handling factors
Incorrect storage of insulin or poor injection technique can affect insulin therapy. Ask owners to demonstrate how they inject their pet, and ask the following:
- Is the insulin being stored correctly?
- Is the insulin being mixed properly?
- Is the insulin being injected subcutaneously?
- Is the injection site being correctly located?
- Is the injection site being rotated?
If using a syringe:
- How long has the vial been in use?
- Is the correct dose being drawn up into the syringe?
- Is a new syringe being used for each injection?
- Have the air bubbles been removed from the syringe during dose measurement?
If using VetPen:
- Is the insulin cartridge inserted into the VetPen properly?
- Have the air bubbles been removed from the VetPen cartridge?
- Is a new needle being used for each injection?
- Is the correct dose being chosen using the dose selector?
- Is the release button being pushed down fully so that the dose selector returns to the start line?
- Is the movement of the dose selector restricted by the way the VetPen is being held?
- Is the needle being held in the skin for at least 5 seconds after the dose selector has returned to the start line?
Antibodies may be directed either against the insulin or against other foreign proteins in the preparation. The presence of anti-insulin antibodies is common and does not usually lead to poor regulation. Antibody production is less likely if homologous insulin (has the same structure as the recipient) is given, e.g. the porcine insulin (in Caninsulin) has the same structure as canine insulin9.
Stabilising diabetes long-term in dogs
Help clients understand that their dogs can live healthy, active lives when their dog’s diabetes is properly regulated.
Once the maintenance dose has been established and the dog is stable, a long-term management program must be implemented. The aim is to minimise variations in insulin requirement. This includes monitoring to detect underdosage or overdosage of insulin, and adjustment of dose, if required. Careful monitoring during maintenance will help limit most of the chronic problems associated with diabetes.
Various approaches to maintenance have been described. The most clinically accepted approach is to ask the owner to monitor and record their dog’s general health (including well-being, thirst and appetite) daily. Urine glucose checking at home should only be used where appropriate, such as when hypoglycaemia is suspected and a negative morning glucose would indicate an insulin overdose10. Dogs should be checked by a vet every 2 to 4 months (more often if there are problems) for general health (and absence of clinical signs), urine glucose and blood glucose as required and indicated by the general health check and owner diary. Adjustments to the insulin dose must be based on full analysis of clinical data and a series of blood glucose measurements.
Other health factors
The use of progestogens in dogs suffering from diabetes mellitus should be avoided. Ovariohysterectomy should be considered for entire bitches. Stress and irregular exercise must be avoided. Care must be taken with the use of corticosteroids. It is important to establish a strict feeding schedule in consultation with the owner that is consistent and avoids too many fluctuations and changes10.
Clinical signs to watch for
It is extremely important that owners can recognise the signs of hypo- or hyperglycaemia and respond appropriately. Polyuria, polydipsia, and polyphagia in combination with weight loss, poor condition, loss of hair or hirsutism and lethargy are the most common clinical signs of hyperglycaemia and require administration of insulin to restore blood glucose levels to an acceptable range.
However, these clinical signs may also be present as a result of a rebound hyperglycaemia secondary to a hypoglycaemic episode (Somogyi overswing). While a blood glucose curve can help differentiate between insufficient insulin dosing and Somogyi overswing, the results can be confusing if the rebound hyperglycaemia persists for a few days and may not be associated with the time of insulin administration. Evaluating weight changes in the patient can help shed some light on this issue. If the dog is losing weight and exhibiting clinical signs of diabetes mellitus, the insulin dose may be insufficient. If the dog is gaining weight but continues to have clinical signs consistent with diabetes mellitus, the insulin dose may be excessive, and causing Somogyi overswing.
The signs of hypoglycaemia may occur suddenly and can be life-threatening, so it is important owners are very aware of these and know how to respond. Signs include lethargy or dullness, restlessness and anxiety, weakness and a staggering gait and muscle twitching / shivering. If not treated, these can lead to convulsions, coma and, eventually, can be fatal.
- Caninsulin Summary of Product Characteristics (SPC)
- Ackerman, N. et al (2018). Diabetes mellitus: Guidance for managing diabetes in practice. Companion Animal;23:143-151.
- Behrend, E., Holford, A., Lathan, P., Rucinsky, R. & Schulman, R. (2018). 2018 AAHA Diabetes Management Guidelines for Dogs and Cat. www. JAAHA.org
- Fleeman, L.M., Rand, J.S., & Morton, J.M. (2009). Pharmacokinetics and pharmscodynamics of porcine insulin zinc suspension in eight diabetic dogs. Vet. Record; 164, pp 232-237.
- Munroe, W. E., Laxton, D., Fallin, E. A., Richter, K. P., Santen, D. R., Panciera, D. L., Towell, T. L., Williams, K. A., Hart, J. R., Hill, S., Finkler, M. R. & Shinn, J. S. (2005) Efficacy and safety of a purified porcine insulin zinc suspension for managing diabetes mellitus in dogs. Journal of Veterinary Internal Medicine; 19, pp 675-682
- Behrend E, Holford A, Lathan P et al. AAHA Diabetes Management Guidelines for Dogs and CatsJ Am AnimHosp Assoc. 2018; 54:1–21.
- 1 Lust E, van Esch K, Slingerland LI, Kooistra HS, Horspool LJI. Survey of Veterinary Professional and Pet Owner VetPen User Experience. Presented at the 42nd WSAVA and FECAVA 23rd Eurocongress; Copenhagen, Denmark; 25-28 September 2017
- Burgaud, S., Riant, S. & Piau, N. (2012). Comparative laboratory evolution of dose delivery using a veterinary insulin pen. WSAVA Poster
- L.J. Davison, B. Walding, M.E. Herrtage and B. Catchpole. Anti-Insulin Antibodies in Diabetic Dogs Before and After Treatment with Different Insulin Preparations. J Vet Intern Med 2008;22:1317-1325
- Behrend E, Holford A, Lathan P et al. AAHA Diabetes Management Guidelines for Dogs and Cats J Am AnimHosp Assoc. 2018; 54:1–21.
Caninsulin® 40 iu/ml Suspension for Injection contains an aqueous suspension of insulin containing 40 i.u. highly purified porcine insulin, which is structurally identical to canine insulin. POM-V
MSD Animal Health UK Limited. Registered office Walton Manor, Walton, Milton Keynes MK7 7AJ, UK. Registered in England & Wales no. 946942.
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