Diabetes in Pets


Tight regulation (TR) refers to the goal of keeping your pet’s blood glucose within non-diabetic levels, also called euglycemia, 100% of the time. For cats, euglycemia ranges from 60-130 mg/dL, or 3.3 to 7.2 mmol/mL.

Tight regulation was studied in humans in a famous 10-year study called the Diabetes Control and Complications Trial (DCCT)[1][2] that compared the incidence of diabetic complications between tightly regulated and traditionally regulated diabetics. The tightly-regulated patients showed:

  • 76% reduced risk of eye disease
  • 50% reduced risk of kidney disease
  • 60% reduced risk of nerve disease

Based on these results, everyone in the control group was put on a program of tight regulation before the end of the study. Since this study, the target range for humans has been lowered significantly.

Unfortunately, no such studies have been conducted for dogs and cats, and vets continue to target glucose levels that are well above euglycemic range. However, some vets claim that tight regulation for cats will result in increased levels of remission[1].


Commonly, three insulins are used for Tight Regulation in cats:

Lantus and Levemir are very similar in terms of duration and potency in humans[3]. Lantus and Levemir also appear to have very similar action profiles in cats, but there are still too few cats on Levemir to say this with certainty.

The most often recommended protocol for cats is "Start Low Go Slow"[4], which does not emphasize Tight Regulation, though it can be used that way if the insulin and the cat permit it. See Regulation for more details.

It's also possible, using the three insulins above and in some cases, short-acting boosters, to attempt tight regulation in cats. The following protocols show how.

If you choose to follow one of these protocols, please inform yourself thoroughly before you start. These protocols don’t just involve giving insulin and measuring blood glucose values, but there are also important dietary prerequisites (a low-carb canned or raw diet) and other factors you should be aware of[5].

On the other hand, these protocols are nothing to be afraid of either and can be used by people new to feline diabetes: all that is required is time to dedicate, a thorough understanding of the methods, and their careful applicaton.

"Dr. Hodgkins' Protocol" with PZI[]

A good TR protocol for regulating and inducing remission in cats with PZI was developed by Dr. Hodgkins[6]. Her protocol uses PZI insulin, which has a shorter duration than Lantus or Levemir, therefore it is injected mostly TID or QID (every 6 to 8 hours) to keep the cat in the normal range for as long as possible. PLEASE NOTE: this protocol ABSOLUTELY requires a low-carb diet (under 10% calories from carbs) of either raw or canned food - no dry foods or treats of any kind are allowed on this protocol.

The protocol uses a sliding scale for insulin dosage, a basic starting version of which is as follows:

This is a BASIC starting scale, for cats with no history of their response to insulin. You may need more or less in some cases. These instructions are for injecting insulin every 6 to 8 hours, when you know that peak is past.

Blood Glucose (US) International Insulin to inject notes
(mg/dL) (mmol/L) (Units)
35-44 2.0 - 2.4 0 (Low, feed/watch cat)
45-54 2.5 - 2.9 0 (Feed cat, test in 2 hours)
55-150 3.0 - 8.2 0 (Normal, test in 2 hours)
151-170 8.3 - 9.4 .5 (if no history)
171-185 9.5 - 10.2 1 (if no history)
186-200 10.3 - 11.1 1.5 (if no history)
201-220 11.2 - 12.2 2 (if no history)
221-250 12.3 - 13.8 2.5 (if no history)
251-290 13.9 - 16.1 3 (if no history)
291-350 16.2 - 19.4 3.5 (if no history)
351-410 19.5 - 22.7 4 (if no history)
411-450 22.8 - 25.0 4.5 (if no history)
451-500 25.1 - 27.8 5 (if no history)

Know your cat -- if blood sugar is rising again 6 hours after shot time, test again after 6 hours. If blood sugar normally continues dropping and doesn't start to rise until 8 hours after shot time, wait 8 hours before testing. All injection instructions assume blood sugar is currently RISING. If unsure, wait an hour and test again.

Again remember that Dr Hodgkin's protocol ABSOLUTELY requires a low-carb diet (under 10% calories from carbohydrate) of either canned or raw food. Please see http://www.yourdiabeticcat.com/ for the original protocol and more information and Dr. Hodgkins' forum. Dr. Hodgkins no longer participates in this forum, but it is still actively being administered by those she trained. Those devotee have also implemented and administer http://www.diabeticcatinternational.com/ which contains more up-to-date information on the newest insulins and foods and acts to guide those new to Dr. Hodgekins' protocol

"Dr. Rand's Protocol" with Lantus[]

Dr. Jacquie Rand[7] has developed and refined a protocol for dosing diabetic cats. Like other Tight Regulation protocols, its goal is to bring most cats into remission. It has been used very successfully in newly diagnosed cats.

This protocol is becoming well-known to vets lately, and some believe that the key innovation is the use of Lantus. It's possible, though, that Levemir with its very similar action profile[8], would work exactly the same way.

Major points of the protocol include:

  • Initial insulin dosing is by ideal weight and relatively aggressive, but there is provision for lowering the dosage in the first 3 days.
  • Goal is to keep blood glucose level below 216 mg/dL (11.9 mmol/L), but above 90 mg/dL (5.0 mmol/L), (72mg/dL or 4.0 mmol/L in well-regulated cats).
  • However, the protocol also mentions that: "To increase the chance of remission, we suggest aiming for perfect control or possibly slightly overdosing during the first 2 months, provided the veterinarian and owner can carefully monitor the cat. There is the potential risk of hypoglycemia, but we believe this is outweighed by the benefit of diabetic remission to the cat and owner."
  • Low-carb diet with a high protein level should be used. Canned food is definitely preferred to dry_food.

Dr. Rand's protocol may be found in various published versions.[9][10][11][12]

"German Protocol" with Lantus and Levemir[]

A good TR protocol has been developed in Germany for Lantus and Levemir. These insulins are injected BID and no sliding scale is used.

This protocol has been developed by members of the TR Lantus Levemir Forum. These people originally founded a Yahoo!Group in October 2004 because they had experienced that TR was the best approach for their cats with Lantus. In March 2006, the founders moved to the new forum.

The logic for a fixed dose on Lantus/Levemir BID is just this: the peak of these insulins is so late and the effect of the dose so long-lasting (well past the next shot), that the dose size is more likely to affect your next preshot than to have any effect on the immediate situation. Nadirs are frequently measured at +10 to +12 hours after injection.

So changing your dose based on immediate numbers doesn't have any relevance: by the time the new dose has an effect, the current number is long-gone. The changed dose just affects the next peak, and you wanted that to be constant anyway.

Here are some key features of the protocol:

  • It works very well in the great majority of cats that it has been used with.
  • Many owners who have been using Lantus, but not this protocol, have had much more trouble regulating their cats and mostly don’t achieve regulation.
  • It should be noted that Caninsulin is the only licensed insulin for cats in Germany and virtually all German cats who use this TR protocol are therefore not newly diagnosed diabetics, but medium to longer-term diabetics. They have been hard to regulate, frequently also on other insulins in addition to Caninsulin and have a lot of beta-cell damage due to glucose toxicity.
  • There have not been any clinical hypoglycemic events under this protocol, while some cats may occasionally have a too low BG.
  • The measurement of ketones in cats using this protocol is extremely rare: and these events can be counted on one hand and usually resulted from an acute infection before the cat has reached regulation.
  • All remissions, with one exception, have been extremely stable.
  • There are several cats that are unlikely ever to go into remission due to complicating factors; the majority of them are well-regulated in the normal range with Lantus/Levemir (mostly 50 to 80 mg/dL (2.8 - 4.4 mmol/L), rarely peaking at 100-120 mg/dL (5.6 - 6.7 mmol/L)).
  • The protocol for TR with Lantus/Levemir was refined over the years and can be read in its most up-to-date form here: http://www.tillydiabetes.net/en_6_protocol2.htm

Links to a number of Excel spreadsheets and one JPG of cats who use this protocol can be found here (they are pretty language-neutral):

"Start Low Go Fast" Protocol with Boosters[]

Steve and Jock have developed this aggressive protocol for quickly regulating cats, assuming that both a long-acting insulin and a short-acting booster insulin are available, and at least the booster is well-known in its effect on the cat. (Note that NPH is sometimes considered "short-acting" in cats, and is suggested here as a booster). The approach has been field-tested on 2 cats (Case:Smokey and Case:Jock) successfully so far. Advantages include lowered risk of DKA, shorter time in hyperglycemia, and faster regulation.


The idea is to start with frequent doses of a booster insulin, enough to keep blood sugar down in mid-high levels (150-250) most of the time. Each booster dose is based on the current preshot value.

Then add in a deliberately low dose of long-acting insulin (Levemir,Lantus, or PZI), at the same time, and gradually raise that dose as fast as safely possible. The booster doses will gradually reduce at the same time. Ideally the boosters will become unnecessary as the slow insulin takes over.


1. Know your R or N booster, and how many units it takes to bring your cat down to about 100 (5.5mmol), 150 (8.3), and 200 (11.0)see blood glucose levels. If you don't know this, you must

a) find out exactly when that booster peaks in your cat.
b) calibrate the dosage by experimenting with small boosters and testing at booster peak time.

2. If you have some idea where your long-lasting insulin dose should be (because you have just switched from another long-lasting insulin, or because you had regulation on this insulin up until recently), start at about 50% of that dose. If not, start it at a dose a bit lower than your usual booster dose.

3. Inject R every 4 hours, or N every 6 hours, as needed, in whatever amount is needed at that time to bring the BG down to these targets:

  • at preshot, aim for 150 (8.3 mmol) at booster's next peak
  • at +4, aim for 200 (11.0) at booster's next peak
  • at +6 or +8, aim for 250 (14.0) at booster's next peak.

If the amount of booster needed to bring your cat from about 400 (22.2 mmol) down to 150 (8.3) is:

  • 1 unit or less: Follow low-dose instructions
  • 3 units or less: Follow medium-dose instructions
  • more than 3 units: Follow high-dose instructions

4. While continuing this R (at PS, +4, +8) or N dosing (at PS and +6) as needed, start the long-lasting insulin doses every 12 hours. The following applies to the long-lasting insulin dose:

a) If there is little or no effect on the R or N dose required, raise the long-lasting insulin dose by:
low-dose: 0.1U every 12 hours
med-dose: 0.2U every 12 hours
hi-dose: 0.5U every 12 hours
b) As soon as a repeatable effect is observed from the long-lasting insulin, slow the raises down to half the above rate.
c) When you are starting to skip R or N boosters (because you are seeing the target numbers without them), slow the raises down by half again or slower if you prefer. At this point if you're feeling in control, lower all the target numbers to taste. (This will depend on the long-lasting insulin and your comfort levels).
d) When you no longer need any R or N boosters (except maybe at Preshot time), stop raising the long-lasting insulin dose. Athis point you should be regulated, and you can adjust the long-lasting insulin dose by small fractions as necessary to maintain that regulation. The boosters may or may not be useful at preshot time.

Additional approaches for cats[]

Some people have had success supplementing their normal insulin with boosters of R/Soluble insulin, as needed. R has a very high potency and can therefore be dangerous: you should be closely supervised by a vet if you choose to use this approach.


In dogs, tight regulation is especially important if the dog still has its eyesight, since blindness can ensue when blood glucose levels stay above 180mg/dL (10mmol/L) for too long. Remaining beyond the renal threshold for glucose for extended periods of time can also mean damage to the kidneys and other vital organs[13][14][15] .

In many dogs it is possible to achieve TR by using a high-fiber diet combined with strategically-timed shots of NPH or Lente insulins. It is also possible to manipulate feeding times to match the way the individual dog metabolizes the insulin. Most dogs are fed 2 equal portions of food 12 hours apart, and receive their insulin after eating. Some achieve optimum results with a 3 or 4 daily meals pattern, dividing the total food portion this way, with injections remaining on a 12 hour cycle.

If TR cannot be achieved this way, the dog should be switched to a basal/bolus regime, similar to that of diabetic humans. There are some dog owners that successfully combine fast or rapid acting insulin (bolus) and intermediate or long-acting insulin (basal), for example. The most common basal/bolus combination for dogs would be use of R//Neutral insulin as bolus and NPH/Isophane insulin as a basal.

Those dogs whose blood glucose levels drop lower than desired at peak time are scheduled for a snack to ensure hypoglycemia won't occur. Learning the individual pattern of highs and lows and using them to one's advantage is the key here.

Further Reading[]