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 onFELINE HEALTH: The Main Forumwhere you'll learn all about home testing, 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 bit more than overwhelming at first. But the good news is that, with appropriate care, a diabetic cat can live as long and as happily as a non-diabetic cat. And some lucky cats will even go into ‘remission’ from their diabetes. By remission we mean that your kitty may be able to have their diabetes controlled by diet alone either temporarily or permanently. 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.

    Humulin N and Novolin N are both brand names for the same insulin, called insulin NPH (Neutral Protamine Hagedorn). Throughout most of this document, and for simplicity’s sake, these will collectively be referred to as ‘N/NPH’ or N.

    Caution! Be absolutely sure that you are using Novolin or Humulin ‘N’. Do not use Novolin or Humulin ‘R'.(The ‘R’, also known as “regular”, insulins are used by vets in medical situations when the blood glucose (BG) needs to be brought down very quickly. It can also be used in other situations where high numbers are present but you should only do with with the guidance of an experienced user.) Also, be sure you are using Humulin N and not Humalog. (Humalog is the brand name for lispro which is also a fast-acting insulin, similar to R.) These guidelines do not support the use of combination insulin such as Mixtard nor do we recommend a combination short- and intermediate-acting insulin in cats.


    In cats, N/NPH is an intermediate acting, recombinant human insulin. It tends to be a faster-acting insulin than Lantus or Prozinc but longer acting than R and some other types of insulin.

    Please note: The current guidelines for the treatment of feline diabetes published by the American Animal Hospital Association (AAHA) in 2018 no longer recommend N/NPH for the treatment of FD. It continues to be recommended for dogs but the AAHA noted that this type of insulin has insufficient duration to be recommended for the treatment of feline diabetes. However, given the cost of longer acting insulin in the US, N/NPH may be a more economical option if finances are a concern. (Many people in the US buy their insulin from a Canadian pharmacy. If you prefer to use Lantus or Levemir, information on buying from Canada is available on FDMB.)

    N/NPH can start acting very quickly after it’s injected and it can drop the BG steeply in the first hours of the insulin cycle. It is therefore critical that you learn to test your cat's BG at home (‘home test’) as soon as possible. It is also important that you become familiar with the effects of N/NPH in your cat’s system. Because it is intermediate in its action and has an early onset, many cats do not get a long duration. Most often, the effects of N/NPH wear off by 8 hours after injection. However, how long the insulin lasts depends on the individual cat. A favorite saying, Every Cat Is Different (ECID), truly applies.

    NPH is available as an injectable suspension. It is available in 3 forms:
      • 10 ml vial
      • 3 ml vial/cartridge
      • 3 ml Kwikpen
    • N/NPH is a ‘U100’ insulin; it has 100 units of insulin per ml. It needs to be used with corresponding U100 syringes. We recommend buying U100, 3/10cc syringes that have half-unit markings.
    • Make sure you are using the correct syringes. Using the wrong syringe could result in your giving cat the wrong insulin dose. In the US, U100 syringes have an orange cap. If you are switching from a different insulin that has a different concentration (e.g.., a U40 insulin such as Caninsulin/Vetsulin), do not use the same syringes. Check the package or syringe barrel to make sure it actually says ‘U100’.
    • Mixing before use: N/NPH is a suspension and must be mixed before use. This is usually done by rolling the container between the palms of your hands and/or inverting the vial or cartridge a few times. The color should be evenly ‘milky’ after mixing.
    • If there are white specks in the insulin or deposits stuck to the inside of the vial, the insulin needs to be replaced.
    • Storage and shelf life: The different brands of NPH, Novolin N, and Humulin N, may have slightly different instructions about storage and shelf life on the package inserts. Please refer to the package insert for information about your insulin.
    • Make sure to not accidently freeze your insulin. If you freeze your insulin, please replace it.

    • If you have reason to be concerned about hypoglycemia or if your cat won't eat, do not give insulin. Post on the main Health board, here, and/or contact your vet.
    • Don’t ever inject N/NPH if your cat hasn’t eaten.
    • Don’t ever inject insulin twice! If you are not be sure if you’ve given an insulin shot correctly, noticed that the fur seems wet where you’ve injected (a 'fur shot'), or think you’ve only injected a portion of the dose, never repeat the shot/injection. You can never be absolutely certain how much insulin got where it was supposed to go. If you re-shoot, you risk overdosing your cat. Better too little insulin than too much in order to keep your cat safe.
    • If your cat has a history of diabetic ketoacidosis (DKA) and his behavior seems “off” or your cat is lethargic, please test your cat’s urine for ketones. If you are new to FD and you have ketones present, post immediately on the Health board as this could be an emergency situation. You can purchase Ketostix at any pharmacy or if your cat has a history of DKA, you may want to purchase a blood ketone meter.

    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/Vetsulinthis 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.


    Please remember to post on this forum or on the Health forum if you are worried about a low pre-shot number or have a question that needs immediate attention.

    With an insulin with an early onset, it is important that your cat has eaten before you give a shot. Generally, you want to feed your cat and give a shot an hour after your cat has eaten. The order for this process is:
    (1) test, (2) feed, (3) wait 60 min, (4) shoot

    Remember: Insulin is given twice a day at 12-hour intervals.

    Starting Dose:
    • For a cat that is eating dry food or other higher (over 10%) carbohydrate food, the starting dose is 1.0u.
    • If the cat is eating a low carbohydrate (preferably) canned or raw food diet, the starting dose is 0.5u.
    If and when to shoot: Generally speaking, if you are new to managing your cat’s diabetes, it’s recommended that no N/NPH is given if the BG is below 250 mg/dL [13.8 mmol/L] on a human glucose meter. You may wish to use a slightly higher ‘post and ask for help’ number such as 300 mg/dL [16.6 mmol/L] in certain circumstances. Experienced members will guide you through your options if your cat has a lower than expected pre-shot number. As you gain experience, you will be able to lower your threshold for when to shoot.
    • If you are new to managing your cat’s diabetes, we do not recommend shooting a dropping number. Given that N/NPH has a limited duration, it is unlikely that you will see numbers dropping at +11 or +12. However, cats are unpredictable. If this should happen, please check with experienced members on Health or here in order to determine what your options are.
    Note: Because the ‘don’t shoot and ask for help’ threshold levels are often slightly higher for N/NPH insulin than for other insulins, it is particularly important that you monitor your cat’s urine for ketones if your cat has a history of ketones or diabetic ketoacidosis (DKA) or has been testing in high numbers and your cat’s behavior seems “off.”.

    Increasing the Dose
    • If, after at least a week and having gotten a curve, the dose doesn’t seem sufficient, a dose increase should be considered. Doses are increased by no more than 0.25u.
    • Increasing doses of N/NPH needs to be done with great care. If you are new to using N/NPH, post on the board for advice if you are considering dose increases for your cat. If in doubt, consult your vet.
    Decreasing the Dose
    • If your cat’s BG drops to 90 or below, it’s time to reduce the dose,
    • Reduce the dose by 0.25u.
    • 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 the Health forum and ask for input about your dose.
    • As your cat spends increasing amounts of time in normal numbers, your cat’s dose should likewise be decreasing.
    • There are doses that are less than 0.25u – 0.1u, and “some” insulin. You want to gradually reduce the dose.
    • If your cat drops below 90 on “some” insulin, it’s time for an OTJ (off the juice) trial. Over the next 2 weeks, test at your usual pre-shot times. If numbers are staying in the normal range, after 2 weeks your cat is in remission.
    • Remission doesn’t mean your cat’s diabetes is cured. It means your cat’s diabetes is diet controlled. In other words, don’t celebrate by giving your cat carbs! Remember to get weekly tests. If numbers are rising, it’s time for a visit to the vet. Health or dental issues can cause BG numbers to rise so it’s good to get any change outside of normal numbers investigated.


    N/NPH can start to have an effect soon after it’s been injected. It may start to drop BG well within 60 minutes. The point at which the insulin starts to have an effect is called onset. After onset, BG will continue to drop and the process may, in fact, speed up. Be aware that N/NPH typically drops the BG fast, but this is not the case in all cats. Home testing will help you to determine how the insulin works in your cat.

    The lowest BG level of the cycle is referred to either as peak (peak insulin activity) or nadir (lowest BG). Based on forum members’ experiences, the time of the nadir can be quite variable. Depending on your cat’s response to the insulin, nadir can fall between 2 - 6 hours after the insulin shot although in most cats, nadir is between 3 - 5 hours after the injection. With N/NPH it is particularly important to know when the nadir of the cycle typically occurs in your cat.

    The length of time that insulin remains active (lowers BG) in your cat’s system is called the duration. N/NPH typically has a shorter duration than other insulins, with some cats only getting around 8 hours.

    Home testingwill allow you to get a curve which will help you to determine when onset and nadir occur and how much duration you typically see on a given dose of insulin. With NPH, a curve involves testing every hour until nadir and then every 2 hours for a cycle. When first starting out with N/NPH, this may mean that you are testing hourly for most of the cycle for your several days in order to learn when onset and nadir occur and how much duration you’re getting. You will need to repeat curves with a dose change. Knowing these patterns can be extremely useful and will help you to keep your cat safe.


    Q: Is my cat’s BG high enough for insulin?
    There are several things to consider. First, it's generally recommended (especially for newcomers) that a shot of N/NPH isn’t given if the pre-shot BG is below 250 mg/dL [13.8 mmol/L] on a human meter. If you use a pet meter such as AlphaTrak2 you may want to raise the ‘no shoot’ threshold. This gives an added margin of safety when using a pet meter. (If in doubt seek advice from your vet.)

    It’s also important that the BG is definitely rising at the time you give the shot.

    Second, there are some situations in which you may wish to be even more cautious, e.g. if you are new to diabetes, or you can’t test much, or you’re increasing the dose, or reducing the carb content of the cat’s diet. In any of these situations you could consider raising the ‘shoot and ask for help’ threshold initially until you’ve been able to do a BG curve, or at least a partial curve, where you are testing hourly until past the peak of the cycle. A more suitable threshold in these situations might be 300 mg/dL [16.6 mmol/L] on a human meter. If you use a pet meter, such as AlphaTrak2, you may want to raise this threshold. This gives an added margin of safety when using a pet meter. (If in doubt seek advice from your vet.)

    Third, if you’ve gathered a lot of data about how your cat responds to insulin, and this shows that the BG doesn’t drop very fast or far on a given dose, you might consider lowering the ‘shoot and ask for help’ threshold to below 250 mg/dL [13.8 mmol/L] on a human meter.

    However, you need to have a LOT of data to show that it may be safe to give shots at lowered pre-shot levels. Also, you must be confident that you can monitor your cat’s BG and take action if it drops low. Cats who fit in this category seem to be in the minority. And if you are considering reducing your threshold post on the forum first for advice.

    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 250 mg/dL [13.8 mmol/L] on a human meter you can 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 up to at least 250 mg/dL [13.8 mmol/L] on a human meter.

    If using a pet meter, such as Alphatrak2, you may want to raise the number above 250 mg/dL [13.8 mmol/L] to give an added margin of safety. (If in doubt seek advice from your vet.)

    You can repeat the process to see if the cat’s BG reaches a number you can shoot. The difficult aspect of stalling is that it throws your shot schedule off. If you can’t afford to shoot 12 hours after you actually give your cat a shot or if you are in doubt, skip the shot. Another option is to give a smaller dose (affectionately called a BCS – “big chicken sh*t” – dose). If your cat’s pre-shot level is significantly lower than usual, post on the forum for advice about how to proceed. In some instances, because of the short nature of this insulin, you may be able to adjust shot time but post and ask for help.

    Note: If your cat has had ketones or DKA (Diabetic Ketoacidosis) then please post on the forum for further advice if you are considering skipping a shot.

    Q: How low should I let my cat’s BG drop on N/NPH?
    It's advisable to not let the BG drop lower than 100 - 120 mg/dL [5.6 - 6.7 mmol], as measured on a human meter, at the peak of the cycle. (If you are using a pet meter you may want to keep the nadir higher than is suggested for human meters.) N/NPH can drop the BG very sharply indeed. Trying not to let the BG drop below these levels helps to give a margin of safety.

    If you get a BG of 100 - 120 mg/dL [5.6 - 6.7 mmol] on a human meter, and there is still some time to go until the peak of the cycle you may need to take action to insure that the BG doesn’t drop much lower, and monitor closely until past the peak of the cycle.
    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 seek advice from your vet.)

    Important: Ask for help on the forum before giving insulin if you are unsure, as you can never ‘un-shoot’ insulin.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 specific "dose advisers" on the FDMB. The FDMB is an open board subject to peer review where laypersons with varied amounts of knowledge and experience are free to share their own thoughts and opinions through explanation and by making suggestions. We are not veterinarians. It is not our intention to take the place of your veterinarian. Please discuss dosing, methods, medications and care for your cat with your veterinarian.

    Sometimes there are special circumstances such as: the presence of ketones, an unusually low pre-shot number, a caregiver leaving the cat with a sitter, relatively high flat curves, loss of appetite, infection, a schedule change, ability to monitor, etc. which may call for adjustments to these guidelines. Please ask for guidance if any of these or other circumstances present themselves or are of concern.

    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
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