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GLARGINE INSULIN: SOMETHING NEW FOR CATS
Achieving regulation in the diabetic cat can be tricky. In most cats, the human insulin products are either not reliably absorbed from the injection site (a problem for Humulin U in particular)
or they do not last long enough to cover a 24 hour period even with twice a day administration. PZI insulin, currently the insulin of choice for cats, has a reliably long duration most of the time but is expensive
since it became available only for the veterinary market or must be compounded with inconsistent quality control between batches.
In Australia, PZI insulin is not available due to its beef origin and an appropriate insulin for cats was sorely needed.
In human diabetes mellitus, the trend has been towards the use of ultra-short acting synthetic insulin (like Humilog®) at meal time and a once a day long acting peakless insulin
(namely Glargine insulin) to provide a general blood sugar control throughout the day. Glargine insulin (brand name Lantus®) is readily available at any drug store, usually costs less than PZI
insulin, and is designed to be long acting. The million dollar question is this: how well does it work for cats?
So far, studies show it works pretty well and in new diagnosed diabetic cats, it seems to provide such good control (when used in combination with a low carbohydrate diet) that many cats revert to a
non-diabetic status in a matter of weeks (six out of seven cats were in remission after only 4 weeks of glargine therapy). Is it too good to be true? Studies are still on-going and even the glargine researchers in
Australia still say that PZI insulin should remain “insulin of choice” at this time but have released some guidelines on how to use glargine insulin in the cat.
IF YOU WANT TO TRY IT, HERE’S WHAT YOU NEED TO KNOW:
- Glargine insulin cannot be diluted. The feline dose of insulin is generally only a few units of insulin and the gradations on an insulin syringe are tiny. With insulins other than glargine,
dilution is possible to make measuring easier. The long-activity of glargine depends on the formation of small crystals where it is injected. This does not occur if one attempts to dilute glargine.
- Glargine is available in a Pen injector that measures one unit increments but it is expensive, expires in 1 month and cannot be refrigerated. The 10ml bottle of glargine should be
refrigerated to insure best activity as they will last at least 6 months when stored this way. Refrigeration is not as important with other insulin types.
- Eventhough glargine is a long acting insulin, it probably will need to be given twice a day just like other insulins.
- With other insulins, as long as the cat is stable and eating, the owner is taught how to use insulin and the cat is sent home for a few weeks. A glucose curve is performed in 1-2 weeks to assess
the success of the dose and insulin type chosen. Because some cats drop their blood sugars quickly, it is recommended that the cat starting glargine stay in the hospital for the first three days for blood sugar
monitoring.
- Because of the strong chance of a cat going into remission (i.e. becoming non-diabetic), it is important for the cat on glargine to have a curve weekly for the first 4 weeks of treatment.
This many curves may not be needed when other insulins are used or, if they are needed, they need not be scheduled so close to one another. Most cats on glargine have achieved regulation after 10 days.
- Glargine insulin is not for ketoacidotic cats. Shorter acting insulins are needed for the treatment of this serious diabetic complication.
Most veterinarians do not have experience with the use of glargine insulin at this time.
If you wish to try glargine, your veterinarian will need to consult with other experts regarding protocol and dosing details.
The high remission rates reported for diabetic cats
apply to cats newly diagnosed with diabetes.
Other cats who were switched to glargine for better
glucose control after having been diabetic for years
do not tend to revert to non-diabetic status.
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