Hi, I am not a vet. All of my advise is based on my experience with both human and canine diabetes. It is exactly what I would do for my own dog with diabetes.
I would like to discuss an insulin regimen for the dog who is not consistent in his or her eating habits. Let’s say you never know how much they are going to eat at any given meal or if they are going to eat at all. This happens a lot to dogs whose health may be declining due to complications from diabetes or any number of other illnesses. It is also very helpful for the finicky eater.
You would still use a long duration insulin like lantus to cover the basal glucose levels which is glucose secreted by the liver and has nothing to do with meals. Lantus begins to work in 2 to 4 hours, has no peak and lasts for about 24 hrs.
For meals (prandial) glucose control you would use a fast acting insulin like Novolog or Humalog which have a duration of 4 to 5 hours. This would cover the glucose metabolism for any given meal without being tied to a certain time or meal size.
For the unpredictable eater you would inject Humalog or Novolog AFTER a meal. This way you could give the right dose for whatever size meal your unpredictable eater consumed or you could give no dose if they did not eat at all.
The most effective glucose control for dog or human is to cover basal glucose and prandial glucose SEPARATELY with 2 different types of insulin, a rapid onset short duration insulin for meals and a slow onset long duration insulin for liver glucose production which remains pretty constant throughout the day.
Here is a graph that shows the curves of different types of insulin:
http://www.lantus.com/images/hcp/charts/lrg_1.2.3_1.png
The basal graph shows the flat blue line which covers the glucose secreted by the liver. The prandial shows the green line which closely matches the glucose from meals. The graph of the NPH insulin doesn’t closely match anything.
