Vekkie's Diabetes Playground(16KB)

Last updated: Fri, 15 Jan 2010 08:33:32
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Vekkie's Merry Measure

Tales of Measurements

Measuring Insulins

of Two Different Kinds

A Rose Is A Rose

A Rose Is A Rose
A Unit Is A Unit

Photo by Almali

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Fast-Tracking your way through measurements

First Fast-Track draft, Thursday, 28 August 2008; 07:20

Vekkie's series of pages on measuring insulins is long and occasionally complex. She goes at a relaxed pace, giving you time to breathe, to smell the roses, and to enjoy a few of her silly games. She thinks this eases the complexity of certain aspects of measuring insulins, particularly, those that can lead you to converting measurements in order to take advantage of the lovely, sweet, gentle, U-100 syringes, which come with lovely thin, short needles, suitable especially for small dogs, those with thin skin, or for cats.

You would only need to think about converting measurements if your dog (or cat) were prescribed a U-40 insulin, and you were needing, therefore, to use the thicker, longer needles that come on syringes that match; that is, U-40 syringes.

Normally, to make sure not to make errors in dosing, you must use the right syringe for the right insulin, so, if you are using a U-40 insulin, you must use a U-40 syringe. Or, so it is commonly said.

However, it's quite common for people whose dogs are small, or have thin skins, or who have cats, to switch, and to use U-100 syringes with U-40 insulins. People who do this take great care in learning to convert the measurements. It is just too easy to get the dose wrong, and, thereby, to endanger the animal's very life!

Typically, people who make this switch get their veterinarians to show them exactly where, on a U-100 syringe, to measure the dose to, when the insulin is a U-40 insulin. You or your vet could actually mark the barrel of a U-100 syringe, say, with a waterproof marker, to indicate just which barrel-mark is correct for the U-40 insulin dose prescribed. You or your vet, then, would do that for every dose-change.

The entire series of pages here in Merry Measure is intended to help people comprehend such conversions in detail, to help avoid error for those who "use the wrong syringes" (use U-100 syringes with U-40 insulins).

So I recommend that if you use the "Fast-Track" provided here, you also take the time, at least once, to go through the entire series of pages, just to become more familiar with various implications of making such a conversion. And you cannot expect your veterinarian to remember just which human clients are making these conversions, and which are not. And that means, when you talk to your veterinarian about doses, you should use the term "units of insulin." And with a U-40 insulin that would mean, units as measured on a U-40 syringe barrel.

But if you are using U-100 syringes with a U-40 insulin (to take advantage of the thinner, shorter needles) you need to think in terms of "barrel-marks," rather than "units," when measuring your doses. That is because the barrel-marks on a U-100 syringe DO NOT MATCH the number of units in a U-40 insulin.

If your veterinarian approves, you could make the conversions and use U-100 syringes with U-40 insulins. But please remember, if you do that, the responsibility for getting the dose right is yours. Your vet can help. But it is YOU who must remember, if you do this, that you are measuring "barrel-marks" instead of "units," if you use "the wrong syringes." And you should ALSO make sure you understand how many actual UNITS of the U-40 insulin you are giving, so as to be able to converse with your vet about doses!

Units and Barrel-Marks

If you and your vet agree that you may use U-100 syringes with a U-40 insulin, I suggest you use two terms: "units," to mean the actual number of units of U-40 insulin, as measured in a U-40 syringe, you are giving, and "barrel-marks," to mean the mark on the U-100 syringe barrel to which you measure the dose of U-40 insulin.

So, when discussing dose of a U-40 insulin, you would use the term "units," and when discussing the measurement of the dose in a U-100 syringe, you would use the term "barrel-marks."

Purpose of Fast-Tracking through Merry Measure

You can use the Fast-Tracking to review principles of converting from units to barrel-marks, in order to use U-100 syringes with U-40 insulins or to get an idea of the content of Vekkie's Merry Measure. However, Vekkie's entire series is intended to lead you on a sweet adventure, in which the facts you need come along here and there, at a relaxed pace. Vekkie knows that humans, like dogs, learn in instantaneous flashes, so the facts of conversion appear here and there, we trust, in the order needed, allowing you to relax and take your time while you learn. It will surely take you several sessions to wend your way through the entire forest path of this series. But doing so, being on the Slow-Track, should give you something that approaches a kind of intuitive understanding of the conversion you would need if you "use the wrong syringes."

Bon voyage.

You may begin your Fast-Track Journey through Vekkie's Merry Measure here, or you may continue, with the Chapter List, at the Slow-Pace.

Chapter List

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Two commonly-available concentrations

Most of the insulins you would buy at a pharmacy or from your veterinarian will be one of two concentrations. Concentration refers to the amount of biologically-active insulin relative to amount of fluid (suspension) in which the active insulin is dissolved or suspended.

  1. U-40 insulin contains 40 (international) units of biologically-active insulin per milliliter of fluid in which it is suspended.
  2. U-100 insulin contains 100 (international) units of biologically-active insulin per milliliter of fluid in which it is suspended.

Appropriately enough, these insulins are labeled, respectively, "U-40", or "U-100", and those labels should be on the vials of each.

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PREV-Fast-Track (U-40 and U-100 insulins)

Obviously, those two concentrations are very different, so if you're using a U-40 insulin (which has 40 units per milliliter), you will be injecting, relatively speaking, more fluid than you would if you were using a U-100 insulin (which has 100 units per milliliter).

The word "unit" can be very confusing! In one sense, it designates a specific amount of biologically-active insulin contained in the fluid in which it's dissolved, or, "suspended." This specific amount happens to be 1/22 milligrams of biologically-active insulin, which might be in crystalline form.

But suspensions differ from one manufacturer to another, one brand to another, of insulin. The suspension affects how the insulin is absorbed and used by the body. So, there is more to the make-up of one unit of insulin than merely its concentration.

The characteristics and the amount of suspension in which the biologically-active insulin is dissolved varies from one brand of insulin to another.

So there is more to a choice of insulin than just the concentration; the suspension makes a difference, too, and presumably your veterinarian takes that into account when prescribing for your dog (or cat).

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Vekkie and I are anything but experts on the content of various formulas of insulin, but we got a general idea of the principles.

In this Merry Measures group of tales, we explore in slight depth and considerable playfulness, the meaning and significance of (International) Units of Insulin.

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Disclaimer One

The only information contained in Vekkie's Merry Measure that can be said to be accurate is that concerning the concentration of U-40 or U-100 insulins, and the conversion factor if you decide to use syringes intended for U-100 insulins, with U-40 insulins.

All the rest is quite imaginary. Consult your veterinarian if you are treating a dog, or a cat, with insulin. If you want to use U-100 syringes - those marked specifically to measure U-100 insulin - with U-40 insulins, you need to learn the conversion, and to measure accordingly. That conversion is illustrated eventually in Vekkie's Merry Measures.

Syringes are marked to measure insulins of corresponding concentration, and if you get confused about just which markings on the syringe barrel mean what, you can kill your dog (or cat), by delivering too much insulin. You can do the same by delivering too little, though death will be slower in such an instance.

Please do NOT use the material here to make your own conversions, but check with your veterinarian and perhaps your pharmacist as eell

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Disclaimer Two

The name Vetsulin designates an insulin made by Intervet. In the United States, it is called Vetsulin, and in Canada, Europe, and probably some other places on Earth, it is called Caninsulin. It is specifically made for dogs, and is used for some cats as well, and perhaps with some other diabetic animals.

The name Novolin designates a U-100 insulin made by Novo Nordisk. This insulin is a U-100 insulin, made for humans. Quite a few veterinarians will prescribe for dogs, sometimes even cats, insulins made for humans. Many dogs, says my veterinarian, Dr. Amanda Booth, do really well on Novolin NPH insulin, and my Kumbi is living proof that can work well.

As a mnemonic device, Vekkie has shamelessly copied most of these two names to use as examples of U-40 or U-100 insulins. She calls her U-40 insulin "Vetsalin," and her U-100 insulin "Novalin". To prevent confusion, however, Vekkie has given Novalin a Passionate Pink color, and Vetsalin, a Glorious Green color.

Vekkie chose Novalin as her example of a U-100 insulin, rather than Humalin (the real stuff is called "Humulin"); simply because our Kumbi is receiving Novolin. Lilly's Humulin-N insulin is a U-100 insulin similar in many ways to Novolin NPH insulin. The real-world stuff has a slightly milky-white, cloudy appearance, with Novolin being somewhat more opaque than is Vetsulin (or its counterpart, Caninsulin).

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Vekkie and I give special thanks to Jode and Rambo, Angie and Spud, and Marlene and Chelsea, for sending photographs that helped her get sorted out with her Merry Measures, insulins, and syringes. Also, to Bari and Angel for information on measurement markings on vials of Novolin and on BD U-100 syringes purchased in the United States.

More is to come

Vekkie is working away at more Parts for the Parts List.

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DISCLAIMER: Contents on Vekkie's Playground are almost entirely fantasy. Do NOT try to make your own insulin. Obtain what your veterinarian prescribes for your animal, and use that. For any questions about insulin or its measurement and dosage, consult your veterinarian. And do not try swinging from clocks.
All material on this site except where noted is
Copyright © 1995-2014 by Carol Whitney. All rights reserved.
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