What does this mean?

[Delma and Frank]

When selecting a starting dose, it is important to know that while Lantus and Levemir have a longer duration than other insulins, they also have a lower potency in most cats.

Sorry, I'm just not clear understanding this quote. I don't know what it means to say "have a lower potency in most cats". Does this mean that lantus is weaker than say, vetsulin, a shorter acting insulin? Would this then mean that you would end up using more lantus than vetsulin for same efficiency? Before Lantus, Frank was getting about twice as many Units of vetsulin......

(oh , but the syringes were different, too. Now I'm good and confused.)

 

[Larry and Kitties]

Where did the statement come from?

Here is the definition from a chemical dictionary:
"Potency is the dose of drug required to produce a specific effect of given intensity as compared to a standard reference.

"Potency is a comparative rather than an absolute expression of drug activity. Drug potency depends on both affinity and efficacy. Thus, two agonists can be equipotent, but have different intrinsic efficacies with compensating differences in affinity."

My guess it that the per unit of insulin, a longer duration insulin will cause a smaller drop in BG than a sort acting insulin such as N. Also, the typical curve for Lantus is typically very flat compared to a N curve.

 

[Delma and Frank]

Where did the statement come from?

I've seen this statement in FDMB threads ....a FDMB search finds many.

I also read this in a FDMB sticky or was it a link from this site.....not sure .

 

[Delma and Frank]

Where did the statement come from?

Here is the definition from a chemical dictionary:
"Potency is the dose of drug required to produce a specific effect of given intensity as compared to a standard reference.

"Potency is a comparative rather than an absolute expression of drug activity. Drug potency depends on both affinity and efficacy. Thus, two agonists can be equipotent, but have different intrinsic efficacies with compensating differences in affinity."

My guess it that the per unit of insulin, a longer duration insulin will cause a smaller drop in BG than a sort acting insulin such as N. Also, the typical curve for Lantus is typically very flat compared to a N curve.

Thanks for the explanation but now I know that this is waaay to complicated for me to understand at this point in my feline diabetes journey.

 

[tuckers mom]

I've used a few different types of insulin so here's my take on what that statement means

Your cats BGs wont drop a few hundred points when you give an L insulin. Tucker used to go from 300s to 100s in a few hours when we used PZI. Tucker felt pretty crappy when that happened.

We switched to Lev and his BGs were flatter. He felt better, not going from high to low all the time. He was steady, feeling good. It took a bit longer for the insulin to build up in his system but as it did get stored in the "shed" that is often referenced, Tucker's blood sugar started staying lower all the time. His head stopped scrinching, I could tell he didn't have head aches any more.

Tucker's been FD for a while and has lots of other issues, but even with all his issues, the L insulin he's on keeps him feeling the same pretty much all day. No more constant ups and downs.

So, my thought is the word potency simply means your cat's blood sugar wont drop dramatically but will begin to lower over a short time and your cat will feel better all around.

I'm no expert and I hope others can explain this better for you.

 

[Larry and Kitties]

For Tucker's Mom- Using the term L insulin can be very misleading. I think you are referring to Lantus and Levemir. However, a few people (I think) are using Lente insulin which has a longer duration than N but shorter than Ultralente or lantus and Levemir. Lente insulin is commonly just call L insulin.

Back to the original question, I hate it when fact sheets give definitions that are up to the user to figure out what they mean. The use of the words "have a lower potency in most cats" is one example. Another example is saying N is a harsh insulin. What does "harsh" really mean?

 

[tuckers mom]

Larry, you are correct, I think of L insulins as Lantus or Lev, I'll be more specific going forward. Thanks for the catch.

 

[Delma and Frank]

a longer duration insulin will cause a smaller drop in BG than a sort acting insulin such as N. Also, the typical curve for Lantus is typically very flat compared to a N curve.

potency simply means your cat's blood sugar wont drop dramatically but will begin to lower over a short time and your cat will feel better all around.

This does make sense to me...

 

[tuckers mom]

Forgot your question on the syringes. Vetsulin is 40 units per ML (U-40), Lev/Lantus are 100 units per ML(U-100). I'm not a very scientific person so I'll post this link from the Board that explains it a bit.

http://www.felinediabetes.com/insulin-conversions.htm

The second sentence reads: The concentration of the insulin to the diluent determines its strength.

I prefer U-100 needles, they come in different sizes and I like to use the smallest needle, short comfort needles. The U40 needles I believe are one size only, a little longer needle. One of my diabetics, Misty, who passed away, she was like a cat on a hot tin roof at shot time. We were using PZI Idexx U40 strength. I had switched to U100 strength of a different PZI and got the short needles. Misty no longer felt it when I gave her the injection.

Hopefully you'll get used to the U100 needles and maybe have a good experience with them like we did.

 

[Gia and Quirk]

Hi Delma, the answer to your question is going to be a little rant from me and I want to thank you for asking because it illustrates a serious problem on this board.

That statement has been quoted by people who read it and think it is true. They haven't bothered to do their own research and while they think they look intelligent, they don't. This is called parroting. It's lazy and confusing and, like the old game of Telephone, these quotes become misquotes over time.

To answer your question about potencey, the word is inappropriate. Each insulin is as potent as every other insulin. That is required by the FDA and the medical profession. Imagine how doctors would have to deal with different levels of potency--they would be putting every patient at risk for their very lives.

The concept that someone, long ago was trying to communicate, is that because Lantus and Levemir last longer you will end up using less insulin by volume.

As for selecting a starting dose, when you start a new insulin you are starting over with treatment. Half a unit or one unit is the right place unless the cat has acromegaly, Cushing's or a history of DKA.

When lowering a dose you want to test for ketones as often as you can because not enough insulin is one contributing cause of ketone development. It is not the only cause and ketones can develop when the cat is getting the right amount of insulin but is not eating enough or has an infection brewing. Ketones are caused by a combination of factors and insulin may or may not be one of the causes.

Sorry about ranting on your thread, Delma, but I hope your question has been answered and that a few others have learned a thing or two. The most important thing you and everyone else needs to know is that there is no substitute for doing your own research and for posting what you know to be true, not something someone else has said without backup facts.

 

[Larry and Kitties]

I tend to disagree with the following statement:

"The concept that someone, long ago was trying to communicate, is that because Lantus and Levemir last longer you will end up using less insulin by volume."

One international insulin unit is:
"The activity contained in 1/22 milligram of the international standard of zinc-insulin crystals."

The way I look at it one unit of insulin will tie-up/allow cells to use a specific number of glucose molecules. It is like the area under the curve of insulin effectivity vs time will be the same for each type of insulin. Since the onset and duration of the insulins vary, it is two simplistic to say less Levemir/Lantus is required. IT may be that more is required. AN extreme example is if R insulin is used, you get a steep drop with little duration. Thus, you can't give much of R before the BG will go too low. With a longer lasting insulin you should be able to give more since it lasts longer and the drop is less steep. WIth Lantus, it is more complicate since there is a storage shed (see Lantus forum for details) of Lantus in the body and many cats experience a relatively flat (little drop) curve.

 

[Gia and Quirk]

I worried this one over with an MD before I made my statement. R insulin and 70/30 have different properties that are spelled out and acknowledged by the FDA. There are no such limitations for Lantus or Levemir.

 

[Larry and Kitties]

Where it gets confusing is that "Humulin R consists of zinc-insulin crystals dissolved in a clear fluid." and all insulin is compared to that (by definition). Does on have any valid data that really says less Lantus/Levemir insulin necessary compared to other insulins?

Interesting, this human study concluded: "- 76% Higher Dose of Insulin detemir Needed to Achieve Similar, Well Tolerated Glycemic Control Versus Lantus(R)"
http://blog.taragana.com/pr/superior-ef ... emir-6718/

The Lantus site says:"2.3 Converting to LANTUS from other insulin therapies
If changing from a treatment regimen with an intermediate- or long-acting insulin to a regimen with LANTUS, the amount and timing of shorter-acting insulins and doses of any oral anti-diabetic drugs may need to be adjusted.
If transferring patients from once-daily NPH insulin to once-daily LANTUS, the recommended initial LANTUS dose is the same as the dose of NPH that is being discontinued.
If transferring patients from twice-daily NPH insulin to once-daily LANTUS, the recommended initial LANTUS dose is 80% of the total NPH dose that is being discontinued. This dose reduction will lower the likelihood of hypoglycemia [see Warnings and Precautions (5.3)]."
http://products.sanofi-aventis.us/lantus/lantus.html

The two above would imply (for humans) that the dose of Levemir would be more than the dose of N. That the dose of Lantus should be about equal to or maybe 80% of the N dose.

What I conclude is that it is very hard to make general statements regarding dosing of different insulins.

 

[Vicky & Gandalf (GA) & Murrlin]

I call Levemir the Gentle Giant because it is able to maintain blood glucose levels fairly steady over an extended period of time, or duration.

There's nothing "low" about the power behind its ability to do that. That type of wording may give a mistaken impression about the longer duration insulins. Once the shed has built up there is no mistaking their strength.

Perhaps this is a discussion for Think Tank.

 

[Larry and Kitties]

Vicky, the Levemir 101 on the Lantus forum says nothing about a shed for Levemir. The Lantus forum guide mentions a shed for Lantus do some human sites for Lantus.

 

[Libby and Lucy]

FYI, the statement comes from this: http://www.uq.edu.au/ccah/docs/diabetesinfo/link4.pdf (see page 2 at the top, where they outline the starting dose):

Begin with 0.25 IU/kg of ideal weight BID
OR
If the cat received another insulin previously, increase or reduce
the starting dose taking this information into account. Glargine
has a lower potency than lente insulin and PZI in most cats.

The EXACT quote Delma pasted was from http://www.tillydiabetes.net/en_6_protocol2.htm :

When selecting a starting dose, it is important to know that while Lantus and Levemir have a longer duration than other insulins, they also have a lower potency in most cats.

This is Dr. Rand's latest protocol for Lantus/Lev, dated April 2009. Dr. Rand's protocol and the former German Tight Regulation Protocol with Lantus and Levemir are now one and the same. The protocol originated in the German Diabetes-Katzen forum but has since been studied and published by Dr. Rand.

Sorry for the hijack, Delma, but it was asked from where the statement originated.

 

[Delma and Frank]

FYI, the statement comes from this: http://www.uq.edu.au/ccah/docs/diabetesinfo/link4.pdf (see page 2 at the top, where they outline the starting dose):

Begin with 0.25 IU/kg of ideal weight BID
OR
If the cat received another insulin previously, increase or reduce
the starting dose taking this information into account. Glargine
has a lower potency than lente insulin and PZI in most cats.

The EXACT quote Delma pasted was from http://www.tillydiabetes.net/en_6_protocol2.htm :

When selecting a starting dose, it is important to know that while Lantus and Levemir have a longer duration than other insulins, they also have a lower potency in most cats.

This is Dr. Rand's latest protocol for Lantus/Lev, dated April 2009. Dr. Rand's protocol and the former German Tight Regulation Protocol with Lantus and Levemir are now one and the same. The protocol originated in the German Diabetes-Katzen forum but has since been studied and published by Dr. Rand.

Sorry for the hijack, Delma, but it was asked from where the statement originated.

Glad you knew where it came from Libby. I knew I had seen those words somewhere other than in the threads. I didn't know what it meant the first time I read that, and I still didn't know when I read it in a thread today.