Diabetes in Pets
Lente by Intervet
intermediate-acting Porcine
U40 Zinc
Line Intervet
Also known as Vetsulin in US
Similar to  
Action in cats  
  • onset 1-2h,
  • peak 4-6h
  • duration 8h
Action in dogs  
  • onset <1 hour,
  • gentle peak 4-8h,
  • duration 14-24h
Use and Handling
Type cloudy
Shelf Life 24 months
When opened 28 days room temp.
In pen N/A
  • Store Upright at 2-8C
  • Do Not Freeze[1]
  • Do not use if product does not re-suspend[2]

Caninsulin[4], manufactured by Intervet and known in some countries as Vetsulin[5], is a veterinary porcine lente insulin, made up of 30% semilente (short-acting) and 70% ultralente (long acting) insulins.

At present in the US, Caninsulin is FDA-approved for use only in dogs and, just recently, for cats, under the trade name Vetsulin. However, was often used in the US legally "off label" for cats, prior to formal approval.[6].

How it works in dogs[]

The majority of dogs on Caninsulin/Vetsulin (two-thirds) also will require twice-daily[7][8] injections. Intervet says that many dogs stabilize better on twice-daily insulin injections. They also point out that when shots are given twice instead of once daily, there are less hypoglycemia incidents and better blood glucose control[9][10].

Most vets are also not in favor of once-daily use because it is harder to regulate a dog on once-daily insulin than twice-daily dosing[11].

Caninsulin/Vetsulin is a lente insulin, which is classed as intermediate, not long acting. Long acting insulins (such as Lantus,[12][13] Ultralente, PZI) have a poor success rate among dogs.


Vetsulin-Intervet's US name for its U40 pork lente insulin.


Caninsulin: Intervet's U40 pork lente insulin--this is its name in most of the world.

Canine activity graphs[]

For those with dogs, here is a graph of the canine activity.


Human time activity profile for lente insulin. This is the same graphic shown on our Lente page.


Graph from our Lente page turned upside-down and rotated horizontally; it mirrors the glucose pattern shown in the graph above.

Once-daily vs twice-daily injections[]

This blood glucose graph of Somogyi rebound shows a small dog on once-daily porcine lente injections. You can see how the large insulin dose in once-daily regimens produces a steep low at insulin peak. Note: values are shown in mmol/l (non-US) measurement.


Contrast this with a blood glucose graph with a twice-daily insulin regimen where food and insulin are given on a 12 hour basis. Note: values are shown in mmol/l (non-US) measurement.


How it works in cats[]


Feline insulin differs from porcine in three amino acid positions-A-#8, A-#10 and A-#18.

Caninsulin works (somewhat differently) in cats than dogs, sometimes having a shorter duration[14]. Note feline usage was recently approved by the FDA in the US [15], and it is a widely prescribed insulin for cats in other countries.

Caninsulin is a BID (two times a day) insulin[16][17][18]. The bg drop experienced by cats can be a concern if not handled correctly. Because of the (sometimes) steep drop, it is important to make food available around the time of nadir to help "smooth" the curve. This can be done either with a timed feeder or free feeding your cat.

Though some cats can have good results with Caninsulin, (See the case of Butterscotch at Caninsulin-Vetsulin cases) the typical curve, as reproduced here from the manufacturer's website, is very fast-acting and harsh for the first four hours, and doesn't have the duration necessary for 12-hour dosages. If having poor results and it's at all possible to switch to Levemir, Lantus, or PZI insulin, try to do so.

Feline activity graph[]

US scale[]


Int'l scale[]


Further Information[]

Packshot de

Caninsulin/Vetsulin shown in its two presentation forms: 10ml vial (right) and pack of ten 2.5ml vials(left).

It is a veterinary use prescribed insulin and in most countries must either be purchased directly from your vet or with a prescription.

In Canada, Caninsulin is available OTC, or over the counter[19] online. It is also available online with a prescription[20][21] in some countries, and may cost less that way.

Caninsulin and Vetsulin can be purchased in three ways: a pack of ten 2.5ml vials, the more traditional 10 ml vial or a single vial of 2.5ml. Cats and and small dogs can get new vials monthly without wasting.

http://www.intervetusa.com/images/product_photos/VetsulinNew%20frame.jpg                    http://web.archive.org/web/20051013033250/http://www.intervet.fr/Binaries/71_94832.jpg
Vetsulin in ten 2.5ml vial pack and 10ml vial.       French Caninsulin syringes.

Caninsulin/Vetsulin syringes[]

10861 420

Vetsulin syringes--note that the barrel marking on the syringes in the US are black, while Caninsulin syringes have red barrel markings. This is the ONLY difference between the syringes.


Caninsulin 1/2 cc U40 insulin syringe. Note red needle cap designating this syringe is for U40 insulin; syringes for U100 strength insulins have orange caps.

Because Caninsulin is a U40 insulin, U40 syringes are the most helpful. If you choose to use a U100 syringe, you must do the U40 to U100 conversion[22][23]. The conversion is not difficult and can give you precision of 0.2 units for those animals needing a more precise dose.

Caninsulin/Vetsulin branded syringes do not appear the same world-wide. Above is a photo of Caninsulin syringes sold in Italy; French Caninsulin syringes are shown above.

Technical details[]

Caninsulin is a pork-based lente insulin. It is a suspension of crystalline (ultralente) and amorphous (semilente) insulins in a 70/30 ratio, as are all Lente insulins[24].Iletin II Lente[25] by Eli Lilly and Monotard Pork by Novo Nordisk were pork lente insulins. The difference between them is: Vetsulin/Caninsulin is made by Intervet for veterinary use and is a U40 strength insulin--the Lilly and Novo insulins were U100 strength. U40 insulin is more convenient for small animals since it's more dilute and you can therefore give fine doses more easily.


Canine insulin compared with Bovine, Human, & Porcine versions. Up to 2 amino acids differ. Canine and porcine are identical[26].

Caninsulin is an aqueous suspension of insulin containing 40 IU per ml of highly purified porcine insulin (Lente); 30% is amorphous[27] (non-crystallized) zinc (Semilente) insulin and 70% crystalline (in crystal form) zinc (Ultralente) insulin. The difference between Caninsulin and both Iletin II Lente[28] made by Eli Lilly and Monotard Pork[29] made by Novo Nordisk is this: Caninsulin/Vetsulin is a veterinary insulin of U40 strength. Both Novo's and Lilly's insulins were U100 strength.

Caninsulin contains porcine insulin. Porcine insulin is identical to canine insulin[30], but differs from human insulin in respect of one key amino acid. Porcine insulin differs from feline insulin in 3 amino acid positions shown in the table below[31]. Human insulins (i.e. Lantus) differ from from feline insulin by all four key amino acids.

What Lente Is Not[]

No Lente-type insulin regardless of species can contain any NPH/isophane insulin[32] or any R/Neutral insulin[33][34].

Both are chemically impossible: the phenol preservative present in NPH/isophane alters the action of Lente-type insulins, creating a mixture with an approximate action of R/Neutral[35].

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect[36][37].

Lente-type insulins cannot be dispensed in pen or cartridge form because the glass ball used to mix the insulin in these devices will shatter the Lente crystals[38].

Combining Lente Family Insulins[]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with[39] NPH/isophane insulins. The phenol preservatives present in NPH-type insulins alters the Lente-types to the point where they become a close approximation of R/neutral, with regard to action[40][41].

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins[42].

Insulin manufacturers[43] indicate that R/neutral and semilente, Lente, ultralente insulins are able to be combined in the same syringe, but only just before injection. In pre-filled syringes, the zinc suspension of the Lente-type insulins binds the R/neutral, causing it to lose its short-acting effect. Various studies have documented this, and some doctors advise against using R/neutral in the same syringe with the Lente family of insulins[44][45][46][47].

Further Reading[]





  1. Caninsulin-Can I Still Use a Vial of Caninsulin if it Freezes?-FAQ
  2. Caninsulin-What Should Caninsulin Look Like?-FAQ
  3. VetstreamCanis-Intervet UK-Caninsulin
  4. Caninsulin-Pharmacokinetics
  5. Vetsulin Website
  6. http://www.vetsulin.com/PDF/Vetsulin_Dear_Doctor_Letter.pdf
  7. Vetsulin Insulin Requirements
  8. Caninsulin-Twice Daily Regimen for Dogs & Cats (Page 6)
  9. Caninsulin-Starting Insulin in the Healthy Diabetic Patient (Page 4)
  10. Effect of Insulin Dosage on GlycemicResponse in Dogs with Diabetes Mellitus: 221 cases (1993-1998)-Journal of the American Veterinary Association-2000
  11. BD Diabetes-Insulin Injections for Dogs
  12. Fleeman & Rand-Comparison of Pharmacodynamics & Pharmacokinetics of Glargine (Lantus), Protamine Zinc (PZI) & Pork Lente in Dogs
  13. Selecting an Insulin for Treating Diabetes Mellitus in Dogs & Cats-Nelson-OSU Endocrinology Symposium 2006 Page 40
  14. Caninsulin-Page 2
  15. http://www.vetsulin.com/PDF/Vetsulin_Dear_Doctor_Letter.pdf
  16. Caninsulin-Twice Daily Regimen in Dogs and Cats (Page 6)
  17. Caninsulin-Page 2
  18. Caninsulin-Starting Insulin Therapy in the Healthy Diabetic Patient (Page 4)
  19. PetPharm.org-Canadian Shipping Only for Caninsulin
  20. 1800 PetMeds Website
  21. BestPet Pharmacy--UK Only
  22. FDMB-Using U40 Insulin in a U100 Syringe
  23. Using Caninsulin With a U100 Syringe-Page 2
  24. EMEA Scientific Discussion Monotard
  25. US-FDA Iletin II Lente Discontinuation Material 2003
  26. Intervet-Caninsulin-Product Information
  27. Merck Manual Amorphous Definition
  28. Iletin II Lente-Lente Pork Insulin Remedyfind.com
  29. Evaluation of an Insulin Zinc Suspension for Control of naturally Occurring Diabetes Mellitus in Dogs-Australian Veterinary Journal-2000 (Page 3)
  30. Intervet-Caninsulin-Product Information
  31. Amino Acid Sequences
  32. Combining Lente-type Insulins with Phenol-Preserved Insulins
  33. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect
  34. Availability of Soluble (R/Neutral) Insulin in Mixed Preparations With Crystalline (Lente) & Ultralente GE Insulin-Clinical Therapeutics-1991
  35. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination
  36. Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente Diabetes Care-1980
    Note--in 1980, there was only beef Lente-type insulin--no pork or r-DNA/GE/GMLente insulins
  37. Resource Guide-2005-American Diabetes Association
  38. Insulin-Dependent Diabetes--Page 10--Dr. Ragnar Hanas
  39. Phenol Preservatives & Lente-type Insulins--A Bad Combination
  40. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination
  41. RxEd.org-Insulin Therapy-Mixing Precautions
  42. RxEd.org-Insulin Therapy-Mixing Precautions
  43. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins
  44. Availability of Soluble (R/Neutral) Insulin in Mixed Preparations of Crystalline (Lente) & Ultralente GE Insulins-Clinical Therapeutics-1991
  45. Absorption Kinetics & Action Profiles-Single Subcutaneous Administration of Human Soluble (R/Neutral) & Lente Insulin-Diabetes Care-1987
  46. Delayed Onset of Action of Soluble (R/Neutral) Insulin After Premixing With Lente Insulin Diabetes Research & Clinical Practice-1983
  47. RxEd.org-Insulin Therapy-Mixing Precautions
  48. List of POM Veterinary Medications
  49. Current Veterinary POM Medications-UK
  50. DTI-UK-Page 3