Some notes on insulin terms

[k9diabetes]

I was reviewing a page on the U40/U100 conversion for posting to the main website and thought this was be a good time to go over the various terms used to describe insulin since the U40/U100 difference and the conversion to use U40 insulin in a U100 syringe has often been a subject of confusion. Eventually, this information will wind up on the main website.

Type of Insulin

Vetsulin = U40 = 40 international units of insulin in 1 mL of solution.

Novolin/Humulin NPH = U100 = 100 international units of insulin in 1 mL of solution

Filling a Syringe

Syringes are matched to the type of insulin used.

When you fill a U40 syringe with a U40 insulin, each mark on the syringe is 1 unit of insulin.

Fill the U40 syringe to the "10" mark with Vetsulin and you are injecting 10 units of insulin contained in 0.25 mLs of "insulin solution", which is insulin plus a diluent.

40u/mL divided by 4 = 10u/0.25mL

When you fill a U100 syringe with a U100 insulin, each mark on the syringe is 1 unit of insulin.

Fill the U100 syringe to the "10" mark with U100 NPH and you are injecting 10 units of insulin contained in 0.1 mLs of "insulin solution", which is insulin plus a diluent.

U100 insulin has less diluent added to it than U40 insulin so the solution is more concentrated.

Talking about Units versus Marks on a Syringe

When you match the insulin type and syringe type (U40 to U40 or U100 to U100), "marks on the syringe" and "units of insulin" or "dose of insulin" are the same thing.

10 marks on the syringe is 10 units of insulin.

It doesn't matter which insulin you are using, only that the syringe type and the insulin type are matched.

When you DO NOT match the insulin type to the syringe, "marks on the syringe" and "units of insulin" or "dose of insulin" ARE NOT THE SAME THING.

This typically comes up because there are times when it is useful to put U40 insulin in a U100 syringe.

When you do make the conversion, you...

Multiply the units of U40 insulin or dose of U40 insulin x 2.5 and

Fill the U100 syringe to mark on the syringe barrel that corresponds to the conversion.

So, for example, if your dog gets 10 units of Vetsulin per injection and you want to give that 10 units of Vetsulin in a U100 syringe, you...

Multiply 10 units x 2.5 = 25.

Then you fill the U100 syringe to the 25 mark to deliver 10 units of insulin.

Why It Matters

It is extremely important for anyone doing this conversion to understand how many "units of insulin" you are giving.

When you fill that U100 syringe to the 25 mark with Vetsulin, you are giving ONLY 10 UNITS of insulin.

Say your dog is rushed to the emergency room or you go to a new vet and they ask you how many units of insulin you are giving?

If you say 25 instead of 10, your dog is in serious jeopardy.

The emergency or new vet may not find out that there is a conversion factor involved.

So it's important to understand the difference between your dog's insulin dose (the number of units) and the strength of the solution of insulin and diluent your dog's insulin is.

While you can't really compare one insulin to another as dogs react to them all differently, a unit of one insulin is equivalent in terms of physical measurements in molecules to a unit of another type of insulin.

Natalie

[k9diabetes]

Here is a link to a conversion table: http://felinediabetes.com/insulin-conversions.htm

[We Hope]

Just going to add here that some other insulins are also U 100:

Humulin R/Novolin R= U 100 = 100 international units of insulin in 1 mL of solution

Humulin 70/30/Novolin 70/30= U 100 = 100 international units of insulin in 1 mL of solution

Lantus= U 100 = 100 international units of insulin in 1 mL of solution

Humalog/Novolog/Apidra= U 100 = 100 international units of insulin in 1 mL of solution

There's also another U 40 commonly used, but mainly for cats:

PZIVet= U 40 = 40 international units of insulin in 1 mL of solution.

There are also some insulin strengths which can be obtained through a compounding pharmacy. The most common is U 40, but there is a U 50 strength available in beef insulin through a Texas compounding pharmacy, BCP:

http://www.bcpvetpharm.com/products_bovine.htm

"BCP PZI® insulin is available in 100u/ml 5ml or 10ml, 50u/ml 10ml & 40u/ml 10ml."

The compounding pharmacies are able to produce vials of just about any strength insulin required. This compounding pharmacy works with compounding human insulin for pets, but most compounded insulin is beef:

http://members.tripod.com/diabetics_world/pets.htm

Congaree Veterinary Pharmacy
1309-B State Street
Cayce, SC 29033
Toll free: 1-877-939-1335
Fax: 803-939-0073 803-939-1335

http://www.congareevetrx.com/

"PZI r-DNA human insulin. Their general order is for U100 strength in 5ml vials. Pharmacist Terry Fiffick says he has made strengths ranging from U2, U40, U50 and U100."

If you're using one of the not so common strengths of insulin, you'll need to ask your vet the type of syringe to be used with this special prescription.

If you take a look at the U 40 and U 100 syringes, you will see that the U 100 ones seem to have "shorter" units.

http://www.childrenwithdiabetes.com/gifs/products/BDUFS1cc.jpg
http://images.wikia.com/petdiabetes/images/9/9d/40iusyringe.jpg

The U 100 BD 1 cc syringes with varying needle gauges and lengths are on top--the U 40 1 cc Caninsulin/Vetsulin syringe is at bottom.

But if you were to fill both of them and measure how much liquid they hold, each of these would hold a total of 1 cc.

http://petdiabetes.wikia.com/wiki/Syringe#U40_Syringes

http://petdiabetes.wikia.com/wiki/Syringe

Link with tables, etc. on the two types of syringes.

[We Hope]

So what the heck is an International Unit (IU) anyway?

http://en.wikipedia.org/wiki/International_unit

"In pharmacology, the International Unit is a unit of measurement for the amount of a substance, based on measured biological activity or effect.

"The precise definition of one IU differs from substance to substance and is established by international agreement for each substance. There is no equivalence among different substances; for instance, one IU of vitamin E does not contain the same number of milligrams as one IU of vitamin A.

"To define an IU of a substance, the Committee on Biological Standardization of the World Health Organization provides a reference preparation of the substance, arbitrarily sets the number of IUs contained in that preparation, and specifies a biological procedure to compare other preparations of that substance to the reference preparation. The goal in setting the standard is that different preparations with the same biological effect will contain the same number of IUs."

The mass equivalents of 1 IU for selected substances are:

Insulin: 1 IU is the biological equivalent of about 45.5 μg pure crystalline insulin (1/22 mg exactly)

So while one IU of Vitamin A does not equal one IU of Vitamin E, one IU of Vitamin A does equal one IU of Vitamin A anywhere in the world. One IU of insulin, no matter what it's type, species or strength, has to equal that 45.5 micrograms of pure crystalline insulin as the standard no matter who makes it or where in the world it's produced.

What's the criteria for an International Unit of Insulin?

http://www.childrenwithdiabetes.com/download/hanas_insulin.pdf

Page 6

An IU of insulin must lower the bg's of a healthy 2 kg rabbit fasted for 24 hours to a reading of 45 mg/dL in 5 hours.

The link is to a chapter of "Insulin Dependent Diabetes in Children, Adolescents and Adults", by Dr. Ragnar Hanas, who is a pediatrician in Sweden. She generously donated this copy of her book to the website Children With Diabetes.

Even though it's geared toward people, there's a lot people with diabetic pets can learn from it also. Page 5 explains how insulin must break down from its hexamer form into smaller parts called dimers and monomers before it can go into the bloodstream and begin the work of lowering bg's.

Page 6 explains why larger insulin doses have a stronger effect and last longer and why less concentrated insulin is absorbed faster, thus going to work faster than a more concentrated one.

She covers an aspect of insulin's day to day variability in pages 10 and 11 with the Insulin Depot. Dr. Hanas has written this as if she's talking with you--not "at" you--about diabetes. Through the various things such as children's sleepovers and birthday parties, she reminds everyone that life doesn't stop because of diabetes--and that's another thing caregivers of diabetic pets need to keep in mind too.

[k9diabetes]

Bringing forward for discussion about Mickey's insulin and syringes.

[k9diabetes]

Just refreshing this post for new members! :)