Diabetic dogs have been successfully regulated with a variety of different insulins. These insulins are derived from different species and have different potencies and durations of action. In general, the shorter the duration of activity, the more potent will be its effect. Nevertheless, every patient will respond somewhat differently to various insulins, and the choice of which product is used should be individualized. Below is a list of currently available insulins, the species from which they are derived, and their approximate duration of action. Since human and canine insulins are nearly identical, dogs can usually be well regulated with human recombinant products. Cats, on the other hand, have insulin which is most like that of cows and therefore tend to be more easily regulated using insulin derived from beef sources or from beef/pork combinations.
Short-acting insulins currently used in animals:
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Regular insulin is very short acting. It is most commonly used to achieve
initial glucose regulation in a patient with diabetic
ketoacidosis. It is administered intravenously or in the muscle
and is considered to be the most potent insulin. Occasionally it may be
used as part of an insulin mixture (50% NPH + 50% Regular or 70% NPH +
30% Regular) for patients in whom intermediate-duration insulins
(such as NPH or Lente) are not potent enough or have a very late onset
of activity.
Intermediate-acting insulins used in animals:
| INSULIN | Species Source | Concentration | Duration |
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Humulin NPH (Humulin N or Neutral Protamine Hagedorn) is the most commonly used insulin in diabetic dogs. The similarity between natural canine insulin and the human insulin from which this recombinant form derives makes Humulin NPH one of the good insulins to try first. While some diabetics are well-regulated with once-daily administration, most dogs require twice-daily injections. With the exception of NPH Anilin, distributed by Anpro Pharm, pork and beef/pork formulations of NPH insulin (the Iletin insulins) have been discontinued and supplies are likely to be depleted by March of 1999.
Lente insulin is derived from human recombinant and pork or beef/pork sources. Like most animal-derived NPH formulations, pork and beef/pork derivations of Lente (Iletin insulins) have been discontinued, therefore Humulin should be used in the initial regulation of newly diagnosed diabetics. As with NPH, many dogs are easily regulated with twice-daily injections of Humulin Lente.
Long-acting insulins used in animals:
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Humulin Ultralente is a long acting insulin that has found its best use in diabetic cats. Unfortunately, despite the similarity between human and dog insulins the potency and ultimate efficacy of ultralente in dogs is less than ideal, making this an unsuitable first insulin to try in a newly diagnosed diabetic dog.
PZI, or protamine zinc insulin, was off the market for several years and has just recently become available through limited distribution by Anpro Pharm, for use in diabetic cats. Since cat insulin is most like that of beef, it is likely to be at least as efficacious if not more so than Humulin Ultralente.
Recall that by March of 1999, the only insulins likely to be available are the human recombinant formulations (Humulin, for dogs and cats) and PZI (used for cats only).
Specific insulin formulations must be administered with the appropriate insulin syringe which matches the concentration of insulin used.
Insulin must be kept refrigerated (not frozen) at all times, even during transport to a boarding kennel or veterinarian. If you anticipate prolonged exposure to warm or room temperatures, place the insulin in a cooler with an ice pack. Insulin vials must be handled gently; optimum handling of insulin during administration is addressed in the section on how to administer insulin properly.