Discussion in 'Caninsulin / Vetsulin and N / NPH' started by Sienne and Gabby (GA), Jun 28, 2020.

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  1. Sienne and Gabby (GA)

    Sienne and Gabby (GA) Senior Member Moderator

    Dec 28, 2009

    If you're new to the FDMB, please start on FELINE HEALTH: The Main Forum where you'll learn all about hometesting, the basics of feline nutrition, and feline diabetes. Please be sure you read “New? How You Can Help Us Help You!

    Finding out that your beloved kitty is diabetic can feel a more than a bit overwhelming at first. But the good news is that with appropriate care, a diabetic cat can very often live as long and as happily as a non-diabetic cat. Some cats will become tightly regulated or go into remission from their diabetes and be able to have their diabetes controlled by diet alone. Right now it may seem that managing Feline Diabetes (FD) is a steep learning curve to master.

    Be patient. Your confidence in managing your cat’s diabetes will soon grow.


    Your vet has prescribed Caninsulin (Vetsulin). Originally developed for dogs, it is also often prescribed for cats. Because of cats’ faster metabolism, Caninsulin (Vetsulin) may not last in the system a full 12 hours. Typically, it may remain effective for 8 - 12 hours. How long it lasts depends on the individual cat. As we often say, Every Cat Is Different (ECID).

    Recently, the American Animal Hospital Association (AAHA) task force approved the use of this insulin in dogs but not for cats but did note that Vetsulin is approved by the FDA for its use in cats.

    Caninsulin/Vetsulin is available in:
    • a 10 ml vial
    • a 2.7ml cartridge
      • The cartridge comes in 2 sizes:
        • An 8u VetPen that will dose in 0.5u increments
        • A 16u VetPen that will dose in 1.0u increments
    It is your choice which delivery system (vial, cartridge, or cartridge in the pen housing) you use. The dosing method we use requires that doses are changed in 0.25u amounts. If you use the VetPen, you do NOT want to use the pen needles since the smallest amount that can be dispensed from the pens is 0.5u. You will need U40 syringes in order to dispense Vetsulin in smaller doses

    Caninsulin (Vetsulin) is s a ‘U40’ insulin (40 units of insulin per ml). If using syringes please make certain that these are also ‘U40’. Try to get U40 syringes with half-unit markings. In the US, U40 syringes have a red cap.
    • Mixing before use. Caninsulin (Vetsulin) is a suspension and must be mixed before use. Some people invert the vial/cartridge a few times before using; others roll the vial several times between the palms of their hands. In some countries the manufacturer’s advice is that the insulin should be shaken until a uniformly milky suspension is obtained. Any foam from shaking should be allowed to subside before using. The insulin, once mixed, should appear as an even, milky white solution.
    • Storage and shelf life: Keep Caninsulin (Vetsulin) in the refrigerator. Don’t allow it to freeze and don’t store your insulin in the refrigerator door as the temperature is too variable). Store vials upright. For cartridges and the VetPen, the Vetsulin website recommends “...keep cartridges refrigerated. When VetPen is loaded, it can be stored on its side”.
    • Note: Depending on country, the product label may say the insulin should be discarded 21, 28 or 42 days after first opening. Caninsulin (Vetsulin) was tested by the USA manufacturer for 42 days after first use. Some countries’ regulatory authorities do not allow product labels that permit the use of sterile products for more than 21 or 28 days after first opening.
      • Many FDMB members find they can use the insulin for longer than is suggested on the label. But don't assume that you can do this. Sometimes the insulin does lose potency sooner. If you are home testing, and see increased blood glucose (BG) levels in your cat, this may mean the insulin is losing potency.
    • If there are white ‘floaties’ in the insulin or any other form of particulates, your insulin needs to be replaced.

    Technical information: Caninsulin (Vetsulin) is produced by Merck Animal Health (MSD Animal Health outside the USA). It is an intermediate acting (lente) porcine insulin, comprised of 30% ‘amorphous’ and 70% ‘crystalline’ insulin. The amorphous insulin takes effect quickly, the crystalline is released more slowly. In dogs this can result in two peaks of activity. But in cats, because of their faster metabolism, there is usually a single peak. or


    Remember to read the Introduction to the ISG post. You want to be familiar with:
    • Using the spreadsheet
    • How to home test
    • The insulin you are using and making sure you have the correct syringes
    • What to feed your cat
    • What you need in case of an emergency – your Hypo Toolkit and where your emergency veterinary clinic is located
    • What to do if ketones are present or if your cat was recently hospitalized with diabetic ketoacidosis (DKA)

    Your cat should be monitored closely the first three days when starting insulin. Initially, BG levels should be checked at pre-shot, +3, +6, and +9. More monitoring may be needed if your kitty has a strong early response.

    Many people find it easiest to begin on a Friday so they can monitor through the weekend. You can determine what works best for your schedule.

    An important note on when to feed your cat: Because Caninsulin/Vetsulin has an early onset, you want to have fed your cat 20 – 30 minutes before you give a shot. The order for this process is (1) test , (2) feed (3) wait 20 – 30 minutes (4) shoot.

    Some key terms/acronyms that you need to know:

    • BG: Blood glucose. Sometimes called blood sugar.
    • Bounce: a sharp increase in blood glucose. It can be caused by a drop int low numbers, a fast drop in numbers, or a drop into numbers your cat is no longer used to. Bounces can take up to 3 days to resolve.
    • Curve: The shape that the graph makes when the BG numbers are graphed. Generally a full curve refers to testing every 2-3 hours throughout a cycle.
    • Cycle: A cycle is 12 hours. It is the time between shots. There are two cycles each day – an AM and a PM cycle
    • Don’t shoot and ask for help number: This is what you do when you get a pre-shot number that is initially below your comfort level for giving a shot. Do NOT feed your cat. You will want to consider whether to delay, reduce, or skip the shot. Post and other members will walk you through the options. In the first three months, we recommend using 200 as your point for asking for help number. As you collect more data and are confident in your cat’s response, you will be able to shoot lower numbers.
    • ECID: Every cat is different. While these guidelines will help you get started, ultimately you need to learn how your own cat reacts and learn to make adjustments to meet the needs of your cat. This takes time and data.
    • Mid-Cycle: The BG tests that are done between the two shots. Getting tests at different times is important to creating a full picture of how your cat is responding. So some days you can get a +6 test, some days a +4 test, some days a +9 test, etc...
    • Nadir: the lowest blood glucose number during the cycle. With Caninsulin/Vetsulin, this generally falls somewhere around 4 to 4.5 hours after the shot is given.
    • Normal BG: Normal BG for a non-diabetic cat is between 50-120 on a human meter and 68-150 on a pet meter. You will find different ranges listed throughout the internet, but this is the range we’ve found to be most accurate.
    • PS: Pre-shot. This is the BG number that you get right before you give the injection. It is used to make sure that the BG is high enough to safely inject the cat.

    Starting Dose

    • Usually it’s best to start with a low dose of not more than one unit (1.0u), twice a day. The manufacturer recommends a starting dose of 0.25u to 0.5u per kg body weight.
      • If your cat is on a low carbohydrate (less than 10% carb), canned or raw food diet (there are a few select dry foods that are low carb) and blood glucose is less than 380 mg/dL (or < 20 mmol/L) the starting dose should be 0.5u.
      • If your cat is on a diet that is over 10% carb and blood glucose is over 380 mg/dL (or > 20 mmol/L), you can start at 1.0u.
      • If you are transitioning your cat to a low carb diet, your starting dose should be 0.5u.
    • For those new to dealing with feline diabetes we recommend that you post and ask for help if the BG is below 200 mg/dL (11 mmol/L) on a human glucose meter. Please post both here and on the Health forum especially is you see this forum isn’t busy. (For more information on what these numbers mean see ‘Home Blood Glucose Testing’ information below.)

    Changing the Dose

    Hold the starting dose for at least a week UNLESS

    • your cat won’t eat or you suspect hypoglycemia
    • your kitty falls below 90 mg/dL (5 mmol/L). If kitty falls below 90 mg/dL (5 mmol/L) decrease the dose by 0.25 unit immediately.
    After 1 week at a given dose perform a 12-hour curve (i.e., testing every 2 hours) OR perform an 18 hour curve (i.e., testing every 3 hours). Note: Random spot checks are essential in order to "fill in the blanks" on your kitty's spreadsheet. The goal is to learn how low the current dose is dropping kitty prior to making dose adjustments.

    The general guidelines for making dose changes are:
    • If nadirs are more than 150 mg/dl (8.3 mmol/L), increase the dose by 0.25 unit
    • If nadirs are between 90 (5 mmol/L) and 149 mg/dl (8.2 mmol/L), maintain the same dose
    • If nadirs are below 90 mg/dl (5mmol/L), decrease the dose by 0.25 unit
    • HOWEVER, there are some situations which signal that a larger than usual dose reduction is needed. If you are unsure, please post on this forum or in the Health forum and ask for input about your dose.
    As your cat's blood glucose begins to fall mostly in the desired range [lowest point of the curve approaching 100 mg/dl (5.5 mmol/L) and pre-shot value around or below 300 mg/dl (16.6 mmol/L)], lengthen the waiting time between dose increases. If you decide to change another factor (e.g. diet or other medications), don't increase the insulin dose until the other change is complete but decrease the dose if your cat's glucose numbers consistently fall below 90 mg/dl (5.0 mmol/L) as a result of the change.

    Don't be tempted to rush the process along by increasing the dose more quickly or in larger increments no matter how high your cat's blood glucose is! Rushing towards regulation will cost you time in the long run, because you may race past the right dose for your cat.

    Important and Helpful Hints
    • Never inject insulin twice! Sometimes we may not be sure if we’ve given an insulin shot correctly. Perhaps we notice that the fur seems wet where we’ve injected (a 'fur shot'). Even if you see the insulin squirt across the room because you went in one side and out the other when you tented the skin, never repeat the shot/injection. You never know whether or how much insulin went into your cat and you could end up giving too much insulin and your cat’s BG may drop too low.
    • Measuring very small insulin doses. If you are having trouble measuring a small insulin dose in a U40 syringe, you may find it easier to use U100 syringes along with a conversion chart that explains how to measure the correct dose. Before attempting to use a U100 syringe with a U40 insulin, it is vital that you understand how the conversion works, otherwise you could give your cat the wrong dose of insulin. Don’t attempt this without first getting advice on the forum.


    • Caninsulin (Vetsulin) can quite often start to have an effect quite quickly after it’s been injected. The point at which the insulin starts to drop the BG is called onset. After onset, BG will continue to drop for a time and the process may even speed up. Be aware that Caninsulin (Vetsulin) can sometimes drop the BG quite fast.
    • The lowest BG level of the cycle is referred to either as peak (peak insulin activity) or nadir (lowest BG in the cycle). With Caninsulin (Vetsulin) you may see the peak/nadir of the cycle at around 4 - 4.5 hours after the shot. In some cats, nadir may be either earlier or later than this. It may occur as early as 3 hours after the shot, and as late as 7 hours after. The nadir is not a fixed point -- it can and does change.
    • The length of time that insulin remains active (lowers BG) in your cat’s system is called the duration. Caninsulin (Vetsulin) typically has a duration of 8 - 12 hours (depending on the individual cat).
    • If you learn to home test, you should be able to identify when onset, peak /nadir, and duration typically occur on a given dose of insulin. Knowing these patterns can be extremely helpful when it comes to managing your cat's diabetes.

    Do not be tempted to reduce the amount of your cat’s food in hope that this will reduce her overall BG levels. Decreasing calories could be detrimental to your cat’s health. Your cat needs to eat an appropriate amount of food for her size and weight. There are certain circumstances, however, when it is helpful to temporarily withhold food (or rather, to delay feeding): these circumstances are explained further down this section.
    • There are particular considerations when using faster-acting insulins such as Caninsulin (Vetsulin) especially for newcomers or for those with little or no BG test data about how their cat responds. This is because Caninsulin/Vetsulin can sometimes drop the BG fast in the first few hours of the cycle.
    • Because this insulin can drop BG quickly, it is important to feed your cat 20 - 30 minutes before giving insulin. This ensures there is food on board for when the insulin starts to work. So, the sequence would be: (1) Test BG. (2) Feed. (3) Wait 20 - 30 mins. (4) Give the insulin shot. (If you are not yet home testing it is still advisable to feed and then wait before giving the shot).
    • Some caregivers feed a snack (or part of the main meal) an hour and a half to two hours after the shot. This strategy can slow down the rate at which the BG is dropping.
    • If you can determine when your cat's nadir (lowest BG) typically occurs during a 12-hour cycle, you can make food available prior to that time. Again, several small meals spread out before nadir can help to soften fast drops in numbers. Timed feeders can be helpful for caregivers who can’t be there in person to feed their cat.
    • Some caregivers using Caninsulin (Vetsulin) withhold food for the second half of the cycle in order to slow down the rate at which the BG rises as the effect of the insulin wears off. If your cat’s BG rises fast after the peak of the cycle you may find this technique useful.
    • In any case, it can be helpful to withhold food for the two hours prior to a pre-shot BG test. This is just to ensure that the test result is a ‘true’ reading and isn’t influenced by food.


    Blood glucose testing at home (‘home testing’) makes managing your cat’s diabetes much easier and may save your cat’s life. It’s not hard to learn and most of us use glucose meters made for human diabetics.

    Home testing can save you the cost of BG curves and/or fructosamine tests done at the vet’s clinic. You can even do your own BG curves at home, record your results in our color-coded spreadsheet, and share that with your vet. *See below for details on how to set up our spreadsheet (SS)*.
    • Your cat will probably be calmer at home than at the vet’s clinic which often results in a more accurate BG test. The stress of a vet visit can cause your cat’s BG to rise significantly, compared with what it would be at home.
    • Does testing sound scary? RELAX! Your cat’s outer ears have very few nerve endings so the sensation is nothing like if we pricked one of our fingers. It is simply a matter of warming the ear to increase blood flow and get a small sample of blood which is transferred to a test strip in a glucose meter. Many cats come to look forward to being tested since they are rewarded with a treat!
    • Here’s a great how-to link with instructions, photos and video: Hometesting Links and Tips.

    How often should I test my cat’s BG?
    As a minimum and to insure your cat’s safety, always test before you give an insulin shot. This is called a ‘pre-shot’ (PS) test. We call the morning test ‘AMPS’ (a.m. pre-shot); and the evening test ‘PMPS’ (p.m. pre-shot). Pre-shot tests are to ensure your cat’s BG is high enough to warrant being given a dose of insulin. In addition to the pre-shot tests, you want to test at least once during both the AM and PM cycles. Since dose reductions are based on your kitty dropping below 90, you want to be able to catch a dose reduction worthy number. We also recommend that you get a “before bed” test shot every night. That test will let you know if you can go so sleep knowing your cat is in safe numbers. Take a look at experienced members' spreadsheets to get an idea about how frequently people test.

    Important sequence: Test - Feed – Wait - Shoot:
    to see what the BG level is; feed to make sure the cat has food on board; wait 20 - 30 minutes, and then shoot/inject insulin. (For more information see ‘FEEDING SCHEDULES’ above.)

    It is important to test your cat as your schedule permits or as your cat requires. A test, one to two hours after the shot (or sooner depending on when your cat's onset occurs) can be very helpful and can give important clues about what may happen later in the cycle. Some additional mid-cycle tests are always useful, especially when there has been a change in insulin dose or food. If you work during the week, weekends are a good time to get additional BG testing during the day and evening cycles.

    A blood glucose curve can give very useful information, especially early on in the cat’s treatment. After the pre-shot test (and insulin shot) tests are typically done every two hours throughout the cycle. With Caninsulin (Vetsulin) it can be helpful to do tests every hour until the cat's BG has passed the lowest point in the cycle (nadir); this is especially useful if there is reason to believe that the cat's BG is dropping too low or too fast.

    A curve can help you see the pattern of how the insulin works in the cat’s body. It can help you to identify when the insulin starts working (onset), when the lowest BG of the cycle tends to occur (peak/nadir), and how long the insulin lasts in the cat’s system (duration). Be aware though that a curve is just a snapshot of a given day, and every day will be different -- sometimes a little different, sometimes very different. (See also, ‘Understanding ONSET, PEAK / NADIR and DURATION’ further up the page.)

    Note: On FDMB we describe BG tests in terms of the number of hours since insulin was given. So, a test one hour after a shot will be ‘+1’; a test two hours after will be, ‘+2’; etc. This system makes things easy to understand when you post on the forum for advice, especially as members live in different time zones around the world.


    Q: Is my cat’s BG high enough for insulin?
    For those NEW to treating feline diabetes, and/or those who don’t have much data about how their cat responds to insulin, we generally recommend that you post to either this forum or the Health board and ask for help if the pre-shot BG is below 200 mg/dL [11 mmol/L] on a human meter. Experienced members can walk you through the options of what to do if you have a lower than expected pre-shot number.

    Q: It’s time for my cat’s shot, but the BG is a little too low. What now?

    • If your cat’s BG is a bit below 200 mg/dL [11 mmol/L] on a human meter, consider ‘stalling’.
      • Stalling is waiting - without feeding your cat - for 20+ minutes, then retesting to see if the BG has risen to a suitable level.
      • You are looking for a number that is rising, not falling, and is high enough to give insulin.
      • If you have time, you can repeat the stalling process to see if the cat’s BG reaches a number you can shoot.
    • If you cannot stall do to time constraints, if numbers are continuing to drop or if you do not have a supply of strips and high carb food on hand, it will be safer if you skip the shot.
    • Note: As you gain experience with home testing and have gathered data to show how your cat responds to insulin, you will become more confident and better able to shoot progressively lower numbers.
    • Ask for help on the forum before giving insulin if you are unsure, as you can never ‘un-shoot’ insulin.
    • If your cat has history of ketones or DKA, or other health issues, or you are concerned, DO post on the Main Health forum for further advice.

    Q: How low should my cat’s BG drop on Caninsulin/Vetsulin?
    Usually it's best that newcomers aim for a nadir no lower than 90 mg/dL (5 mmol/L) as measured on a human glucose meter. This insulin can drop the BG quite sharply. Trying not to let the BG drop below this level as it gives an initial safety buffer while you are learning the ropes.

    If you are using a pet meter you may want to intervene earlier since pet meters are calibrated differently and typically read higher than human meters.

    Q: My cat has quite variable pre-shot BG levels. Do I use the same dose of insulin each time?

    Possibly. It may be that your cat would be more suited to ‘sliding scale’ dosage. With ‘sliding scale’ the dose varies according to the pre-shot number and the typical rate of drop from a given dose of insulin. This varies in every cat. Post on the forum for advice regarding your cat. However, consider that it takes some time to sort out if the variability is due to your cat adjusting to being on insulin or if a sliding scale dose is truly indicated.

    Q: The insulin isn’t lasting very long in my cat, nowhere near 12 hours. What can I do?

    Some cats do get only a short duration with Caninsulin/Vetsulin. If this happens consistently you may want to consider switching to a longer lasting insulin. Alternatively, if you have gained sufficient experience - and if your schedule permits - it might be possible to give three shots a day instead of two. This needs to be done with great care and is not a technique for a beginner. Do not attempt this without first getting advice on the forum and having an experienced member who is willing to guide you through this process. Practically speaking, shooting every 8 hours is very hard on the caregiver’s schedule since you need to consider being awake to test your cat!

    Q: My cat spends some time in really good numbers and the numbers then increase. What does this mean?

    This means your cat is “bouncing.” If the BG drops too fast this may be sensed as ‘dangerous’ by your cat’s liver and pancreas regardless of whether this is the case. Bouncing can also occur if your cat drops into low numbers or even into numbers your cat is no longer accustomed to. When this happens, the body may seek to protect itself by releasing a stored form of glucose along with counterregulatory hormones, thereby raising the BG to a much higher level. We call this ‘bouncing’ - a common phenomenon that caregivers find to be annoying but it is not dangerous. As said above, it may be possible to slow down the rate that the BG is dropping by feeding a snack. It may also be that a dose reduction is appropriate. DO post here or on the Main Health forum if you need further advice.

    Q: Why is my cat so hungry?
    When initially diagnosed your cat may behave like she is starving. That’s because prolonged high BG and your diabetic cat's pancreas cannot produce sufficient insulin, making it hard for her body to get glucose (the end product of food metabolism) into the cells. This is why many diabetic cats lose weight and are hungry all the time. Once her BG is under better control her appetite should return to normal.

    Your cat may need feeding more than twice a day. Many cats do well on a number of smaller meals fed throughout the day. Some cats can be ‘free fed’ for much of the time.

    Multi-cat households
    It can be helpful to get all cats in a household onto diabetic-friendly food if possible. The best diet for diabetic cats is great for most non-diabetics too.


    BG that is too low can be VERY dangerous.
    Low BG numbers need to be taken very seriously even if your cat is not immediately showing symptoms. Some cats show symptoms early on; some show symptoms when the hypo is moderately advanced; some show symptoms only when the hypo is severe. And some do not show any obvious symptoms at all.

    Remember: ‘Absence of symptoms may not mean absence of dangerously low numbers. Do not ignore your meter in a situation where you are not immediately seeing symptoms. Symptomatic hypoglycemia can be a life-threatening situation. It’s better to catch low numbers and intervene before your cat is symptomatic. We believe in safety first and it’s why home testing is so strongly encouraged.

    (For a list of common hypo symptoms see the link 'Emergency HYPO Instructions' further down the page.)

    Q: What is ‘too low’?
    As a general rule, to prevent symptomatic hypoglycemia we want to keep a diabetic cat’s BG levels above 50 mg/dL (2.8 mmol/L) on a human glucose meter. If you are using a pet meter it would be wise to keep the BG a bit higher. On an AlphaTrak2 meter, for example, you are advised to keep your cat’s BG above 68 mg/dL (3.8 mmol/L).

    If you see these numbers you are advised to take action to ensure that your cat’s BG doesn’t drop any lower. If the cat’s BG drops lower, there is a real risk you cat will become hypoglycemic. (A very small minority of cats may actually show symptoms of hypo at these numbers or even slightly higher.)

    Remember too that with Caninsulin (Vetsulin), it is usually best that newcomers aim for a nadir no lower than 90 mg/dL (5 mmol/L) at the peak action of the cycle as measured on a human meter (see ‘Blood Glucose Reference Information’ above.)

    If you get a BG of 90 mg/dL or 5.0 mmol/L or less on a human meter, and there are still several hours or more before the insulin peaks, you may need to monitor your cat’s BG frequently (e.g., every 15 min. and take any necessary steps to keep the BG at safe levels.

    Note: If you are using a pet meter you may need to keep the nadir higher than is suggested for human meters. (If in doubt, post on the board and/or seek advice from your vet.)

    Raising blood glucose in an emergency:

    The fastest way to raise BG in an emergency is to give high carb (HC) food (usually this is a gravy-based food) or a simple sugar such as glucose syrup, honey, or corn syrup. Be aware that the effect of HC food can wear off quite quickly and you may need to repeat this process. See the document ‘How To Treat A Hypo’ (linked below) for further information; and post on the Main Health forum if you have questions.

    Essential hypo reading:
    Emergency HYPO instructions, Hypo Toolkit
    Hot tip: Read through and print off BOTH of the above documents; the first is a great shopping list. And it's a good idea to print off the ‘How To Treat A Hypo’ document and keep it for reference in an emergency.

    If you need help with low numbers, post right away on the Main Health forum.
    If you don't feel comfortable dealing with the hypo at home, or if hypo symptoms are severe, give syrup/glucose and go to the nearest ER vet clinic immediately. If the trip is more than a few minutes long, bring something high carb along and take your meter. (It’s helpful if you have someone with you so you can care for your kitty while someone else drives.)

    Disclaimer: These are general guidelines which have worked for many cats. However, ‘Every Cat Is Different’. Learn how YOUR cat responds to the combination of food and insulin. Please be aware: There are no ‘dose advisers’ on the FDMB. This is an open board subject to peer review where laypersons with varied amounts of knowledge and experience share their own thoughts and opinions through explanation and by making suggestions. We are not vets. It is not our intention to take the place of your vet. Please discuss dosing, methods, medications, and care for your cat with your vet.

    Written by: Diana & Tom, Elizabeth & Bertie, JanetNJ, Kris & Teasel, MrWorfmen’s Mom, Squalliesmom, Tuxedo Mom, and Yong. With acknowledgments to Sue & Oliver, Robin & BB, and Sweetgrass & The Furries. And first posted on October 30, 2017.

    Edited by Sienne and Gabby (GA), Marje and Gracie, and WendyNeko, 2020
    Last edited: Aug 21, 2020
    CarlieQ and Gavin like this.
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