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Information for owners of Canine's with Diabetes Mellitus 


Diabetes in animals is very similar to that of humans. 
Therefore this page may contain links that are about humans or other animals. 
Background Information about Insulin

When we eat, our bodies break food down into organic compounds, one of which is glucose. 
The cells of our bodies use glucose as a source of energy for movement, growth, repair, and other functions. But before the cells can use glucose, it must move from the bloodstream into the individual cells. This process requires insulin. 

Insulin is produced by the beta cells in the islets of Langerhans in the pancreas. When glucose enters our blood, the pancreas should automatically produce the right amount of insulin to move glucose into our cells. Canines with type 1 diabetes produce no insulin. Felines with type 2 diabetes do not always produce enough insulin. (Felines can be type 1 or 2 and Canines are always type 1)

Insulin Tips:

- NPH cannot be mixed with any Lente (L or U) insulin, they are chemically incompatible.
- Insulin does not have to be refrigerated if kept at a moderate temp., although it is recommended.
- Do not give cold injections, it could cause discomfort.
- Popular opinion is to dispose of opened insulin after 30 days or 100 sticks.
- To prevent abscesses, infections, and discomfort, only use syringes once.
- Rotation of injection sites is recommended.
- It is best to feed before the injection to make sure the animal eats. (generally 30 min. before)
- Human insulins are shorter acting than animal insulins of the same type.
- Never shake "cloudy" insulins. Roll the bottle between the palms of your hands. 

Duration and Peak Times for the Most Common Insulins

Types of Insulin

There are more than 20 types of insulin products available in four basic forms, each with a different time of onset and duration of action. Plus you have caninsulin, vetsulin and pzi for animals. . The decision as to which insulin to choose is based on a veterinarian's preference and experience, and the canine's blood sugar levels. Among the criteria considered in choosing insulin are: 

how soon it starts working in (onset) 

when it works the hardest (peak time)

how long it lasts in the body (duration)

The following table lists some of the more common insulin preparations available today. Onset, peak, and duration of action are approximate for each insulin product, as there may be variability depending on the animal, the injection site, exercise. The key to regulation is consistency!
Insulin type Insulin Brand Starts in (onset) Peaks in (nadir) Gone by (duration)
Rapid Acting Humalog (lispro)
Eli Lilly
10-20 minutes 1.5-2.5 hours 4-5 hrs
Rapid Acting NovoLog (aspart)
Novo Nordisk
10-20 minutes 1.5-2.5 hours 4-5 hrs
Short Acting Humulin R
Eli Lilly

Novolin R
Novo Nordisk

30-45 minutes 2-4 hours 5-7 hours
Intermediate Acting


Humulin N
Eli Lilly

Novolin N
Novo Nordisk

1-3 hours 4-9 hours 14-20 hours
Intermediate Acting
being discontinued
Humulin L
Eli Lilly
2-4 hours 6-12 hours 16-24 hours
Intermediate and short-acting mixtures  Humulin 50/50
Humulin 70/30
Humalog Mix 75/25
Humalog Mix 50/50
Eli Lilly

Novolin 70/30
Novolog Mix 70/30
Novo Nordisk

varies according
to mixture
varies according
to mixture
varies according
to mixture
with peak
being discontinued
Eli Lilly
2-4 hours 8-14 hours 18-24 hours
with little peak
Lantus (glargine)
2 hours 6 hours (slight) 18-26 hours
with little peak
Novo Nordisk
1 hour 8-10 hours 18-24 hours

These are only averages, each pet reacts differently to their insulin. 

Another graph showing duration and peak times of some insulins 
lente and ultralente insulins are being discontinued.

Vetsulin is now available in the United States.

For more information visit their website


Caninsulin is made exclusively for animals, but is not yet available in the United States. It is currently available in Europe, Canada, and Australia from your veterinarian. Intervet is currently in the initial stages of getting government approval for its use in the US. This product however is the same kind of insulin as Lilly's Iletin II porcine mixed insulin zinc suspension (lente), only its more dilute for more accurate dosing in small animals (40iu/ml instead of 100iu/ml).

Caninsulin is a lente product, and contains 30% "fast" insulin (semilente) and 70% "slow" insulin (ultralente).

For additional information visit their website.

excerpts by Peter A. Graham


PZI stands for protamine zinc insulin. This is insulin combined with large quantities of a protein called protamine. This protein slows the absorption of insulin from a subcutaneous site. These preparations have a long duration of action, but might sometimes have the problem of poor insulin absorption that also occasionally affects ultralente preps. PZI can be formulated for any species of insulin. In the UK, the veterinary licensed PZI is bovine.
Peter A. Graham
How do I store my insulin?

Frequently Asked Questions About Insulin
Preparing a single dose of insulin
Preparing a mixed dose of insulin
Injecting Insulin
Insulin Administration & Proper Usage
Insulin by Jennifer Prince, D.V.M.
All About Insulin
Insulin Pens 
Tips On Humalog 
Tips on Lantus 
Human Insulin 70/30 
Human Insulin Regular (R) - RxList Generic Information 
Human Insulin NPH - RxList Generic Information 
Insulin Survey in Dogs 
Questions about Insulin 
Insulin Resistance 

BDô INJECT-EASE® Automatic Injector
Painful Insulin Injections in Pets - Tips - Why you should not reuse needles
Can I Prefill Insulin Syringes
Should I give insulin if my pet is ill?
Diabetes Mellitus | Insulin | Your Care Kit | FAQs | Blood Glucose Chart
Sissy and Dakota | Canine Cuisine | Glossary | Mail Lists | Bookmarks
Ken's Daisys Home Blood Glucose Test Site | Pets with Diabetes
Feline Diabetes | Diabetes Mellitus Pet Diabetes Database
The information on this site is general, and should not be used as a substitute
for advice from your veterinarian. Questions concerning your pet's health 
should be directed to your pet's health care provider.