Tilly's Diabetes Homepage

Tight Regulation with Lantus®or Levemir®
for Diabetic Cats


• see your vet and get his or her approval of this protocol before you start!!!
• talk to your vet regularly about your cat's progress
• see your vet immediately if your cat develops additional problems (e.g. ketones, hypoglycemia, vomiting, fever, bladder infections, etc)

Read this first

• this protocol was developed by lay people, including myself, who are members of the German Diabetes-Katzen Forum. It has since been published in the Journal of Feline Medicine and Surgery.
• the majority of cats do very well on this protocol, some cats do not (generally these are hard-to-regulate cats)
• it is more time-consuming than most other protocols, but still definitely doable if you work a regular full-time work week
• it is more expensive than most other protocols, but costs can be reduced by e.g. buying glucose test strips from online pharmacies or reputable sellers at eBay
• members of the German Diabetes-Katzen Forum buy 3 ml Lantus/Levemir cartridges, refrigerate them after opening and routinely use them for 6 months or more - when refrigerated, opened cartridges of these insulins are extraordinarily stable
• you will need to test the blood glucose levels of your cat multiple times per day
• you will need to know about hypoglycemia and be prepared to deal with it
• you will need to test for ketones regularly to start with and know about ketoacidosis, but be aware that ketones don't occur once a cat is (and remains) properly regulated
• you will need a brand-name glucometer made for human diabetics which uses 0.6 ÁL of blood per test or less. While this protocol was originally developed with glucometers that measured whole blood, many have used it successfully with newer plasma-equivalent glucometers.
• you will need to use syringes which allow you to measure tiny doses: U100-type, 3/10 cc = 0.3 ml volume and with the half-unit printed on the barrel
• you will need to feed the right diet: high-quality low-carb canned food or raw food exclusively
• you will need to feed your cat lots of small meals spread over the day, free-feeding canned food can be an option for some cats

Phase 1: Starting dose

In many cases, the starting dose of Lantus or Levemir has been 0.25 IU per kg of the cat's ideal weight and is always dosed BID (two times a day, 12 hours apart). If the cat received another kind of insulin previously, the starting dose should be raised or lowered by taking this information into account. When selecting a starting dose, it is important to know that while Lantus and Levemir have a longer duration than other insulins, they also have a lower potency in most cats.

The cat should be monitored closely on the first 3 days on Lantus/Levemir: do curves between the AM and PM-doses, e.g. AM pre-shot, +3 hours, +6 hours, +9 hours, PM pre-shot. Generally the starting dose is kept for 3 days. Test for ketones daily. Cats that have a tendency to get ketones and/or who are getting relatively high flat curves after the switch should have their dose raised earlier (after 24-48 hours). It is extremely rare that a cat will need to have its dose reduced in the first 3 days, but if the cat falls below 50 mg/dl, reduce the dose.

Measuring curves regularly is important, as well as measuring all pre-shots and taking random spot checks. It is important to know that most cats do not have reproducibly-timed nadirs. It also is not uncommon for a nadir to occur at +12 hours after a shot. If you are fortunate to have a cat with a very reproducible response, you can test less often than with a cat that has a varied response.

Phase 2: Increasing the dose

Most cats need to have their dose increased. Do it in 0.25 IU or 0.5 IU steps (0.25 IU if the cat is getting a low dose and/or relatively low BGs, 0.5 IU if the cat is getting a higher dose and/or relatively high BGs). Hold each dose for 5-7 days. However, if the cat is producing continuously high BGs (nadir always >=300 mg/dl), only hold the dose for 2-3 days before increasing it by 0.5 IU. Alternatively, if the cat is continuously producing moderately elevated BGs (nadir always >=200 mg/dl), increase the dose every 2-3 days by 0.25 IU ( if the cat is getting a low dose) or 0.5 IU (if the cat is getting a higher dose). From this point onward test for ketones once per week, or more often if the nadirs are still >=200 mg/dl.

Many cats will occasionally react to an increased dose with increased BGs - within the first 2 to 3 days after an increase, usually lasting for less than 24 hours. Nobody really knows what the reason for this phenomenon is (perhaps a "panicky liver"?) - hold the dose and ignore the fluctuations.

It is likely, because of the way Lantus and Levemir work (they appear to work for >12 hours, therefore producing overlap between doses), you will face the problem of having a low pre-shot BG and wondering what dose you should give. Try reducing the dose the first few times to see what happens - in all likelihood the cat will have higher BGs as a result. A second alternative is to feed the cat, wait 1 to 2 hours, test again, and when the BGs start rising, give the normal dose. A third alternative is to split the dose: feed the cat, give most of the dose immediately and give the remainder 1 to 2 hours later when the BGs start rising. However, in most cats none of these alternatives have shown themselves to work as well as consistent dosing. You will have to learn how your cat reacts to Lantus/Levemir before you determine the best way to deal with this problem.

Try to find a way to dose as consistently as possible, time-wise and dose-wise: sliding scales don't work. Don't skip shots. Fluctuations are very common in this phase before BGs start to stabilize under consistent dosing: a typical curve of cat over the first 1.5 months on Lantus can be seen here.

When the cat first begins to have daily nadirs in the normal range of a healthy cat (50 to 80 mg/dl) and spends significant amounts of time in this range each day, stop increasing the dose and switch to Phase 3. It doesn't matter when you measure these lower BGs, it can be at pre-shot or sometime between shots. Getting to this point generally takes 1 month, sometimes a lot longer. Cats are extremely variable in terms of the maximum dose they end up requiring: they have ranged from 0.5 IU to 10.0 IU BID in the German forum, with most cats lying between 1.0 IU and 5.0 IU BID.

Be aware that experimental studies in human diabetics over the last 15-20 have rejected the existence of the Somogyi effect (sometimes also called rebound). In cats, no studies have ever been done which properly demonstrate that such a phenomenon exists. Therefore, adjust the dose as described above, focusing on the nadir: don't do so-called rebound checks, as they only lead to unnecessary (and unhealthy!) hyperglycemia.

Phase 3: Holding the dose

Try to keep the cat at a dose where the BGs are in the 50 to 200 mg/dl range for as much of the day as possible. The majority of cats are actually able to achieve consistent BGs in the 50 to <100 mg/dl range with consistent dosing. A well regulated cat looks like this.

Don't let the cat go below 50 mg/dl (N.B. there are some cats that do well with BGs >=40 mg/dl and are difficult to regulate unless the dose is held at BGs in this range, but a cautious approach should be used until you are sure your cat reacts this way). 200 to 220 mg/dl is approximately the renal threshold for glucose and important for renal health and general recovery. This phase may last a long time (many months). Periodic slight adjustments are necessary in many cases.

If your cat remains in this range, testing for ketones is no longer necessary. But if your cat should, for example, develop an infection and suddenly have higher BGs as a result, start testing for ketones immediately and adjust the dose appropriately.

Phase 4: Reducing the dose

When the cat regularly has its lowest BGs in the normal range of a healthy cat and stays under 100 mg/dl overall for at least one week, attempt to reduce the dose. Alternatively, if the nadir glucose concentration is 40 - <50 mg/dl at least three times on separate days, try lowering the dose. If the cat drops below 40 mg/dl once, reduce the dose immediately! The reduction is done very slowly in a step-by-step manner (0.25 or 0.5 IU increments). At each newly reduced dose, try to make sure the cat is still stable in the normal range before reducing the dose further.

If the cat will not stay in the normal range after a reduction, immediately increase the dose again to the last good dose. Sometimes, a cat can even manage to keep its BGs low for a day or two, but then the BGs begin to rise again because the beta-cells haven't recovered enough yet. Try to go from 0.25 IU to a drop before stopping the insulin completely. Reducing the dose too quickly generally does not work: most cats do not go into remission with fast reductions.

Phase 5: Remission

14 days without insulin and normal blood glucose values. Most remission cats are able to stay in the normal range all of the time (50 to 80 mg/dl), although there are a few cases of sporadic higher and lower BGs. Don't stop feeding low-carb and try to avoid cortisone if possible. Test the cat's BGs once per month.

Approximately 25% cats that achieved remission using this protocol relapsed and required insulin again (frequent causes are hyperthyroidism or bouts of pancreatitis). Therefore, it is important to keep your diabetes kit up-to-date. Then you can react immediately by giving insulin and home testing. Importantly, the sooner you react to a relapse (i.e. preventing hyperglycemia and initiating other necessary veterinary treatment), the more likely a second remission will become.

The longer a cat has had diabetes, the less likely it will go into remission. Many long-term diabetics get stuck in Phase 3 or 4. Yet there is a benefit of using this method for such a cat as well: keeping the cat's BG levels as normal as possible is much healthier for it long term. Insulin requirements will often decrease to very low levels too.

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