Converting from Vetsulin to Lantus?

[jangell2]

I need to figure a starting dose for the Lantus. Since Lantus is u100 and vetsulin is u40, the Lantus 2.5 times the potency per mil. Do I divide the vetsulin dose by 2.5 to come up with the equivalent Lantus dose? It seems to me this would be the starting dose for the Lantus.

 

[Ronnie & Luna]

Hi Johnny,

I checked back to some of your previous threads on the board, and found this one with some info on your kitty.
viewtopic.php?f=19&t=12277&p=136889#p136889

this will help others with questions they may have.

First thing thou, you may want to consider home-testing. Would this be something you'd be willing to start?
Here is a link to the FDMB Health Links, including home testing info.
viewforum.php?f=14

After that, doing blood glucose testing will help collect data to determine what insulin, or any insulin is doing.
You've been on a pretty high dose of Vetsulin, do you happen to know your kitty's ideal weight?

Others will be offering suggestions and feedback, but unfortunately, without data collected, it may be rather difficult.
Does your vet have any numbers you can share on recent BG readings?

 

[Monique & Spooky]

I need to figure a starting dose for the Lantus. Since Lantus is u100 and vetsulin is u40, the Lantus 2.5 times the potency per mil. Do I divide the vetsulin dose by 2.5 to come up with the equivalent Lantus dose? It seems to me this would be the starting dose for the Lantus.

Don't try to convert apples into oranges.....Insulin is measured in units and 1 unit equals 1 unit regaurdless of the "strength". We use a syringe that is calibrated for the type of insulin we giving (U40) syringes are usually availble from the vet only a common brand is Teremo they normally have a red cap and the scale is red. For human insulins (Lantus U100) we use a U100 syringe availble from a regular pharmacy, the cap is orange and the scale is usually black. When you fill this syringe to the 2 mark with Lantus you are giving 2 units (2 units of insulin molecules in .02ml of solution) 2 units of an insulin like Vetsulin (U40) given in a U40 syringe is still 2 units of insulin just there is more solution (water) .05ml.

Think of this way if your doctor told you to take 500mg of some drug (in liquid form) and the Adult formula contains 500mg per Teaspoon you would need just 1 Teaspoon. If the pharmacy was out of Adult medicine but sold you instead the Children's formula which contains the same drug but has 250mg per Teaspoon you would simply need to take 2 Teaspoons to get 500mg right?

Are you hometesting? If so and you have arrived at the Vetsulin dose of 2.5U by starting lower and rasing it slowly and you have maintained decent BG numbers then it would be reasonable to begin with the same dose of Lantus (2.5U in the correct syringe). If You are not testing regularly or have poor BG contol then the recommendation would be to start over as if Lantus was the first insulin you have ever given, generally this would be a starting dose of about 1U (sometimes slightly more or less).

It is worth asking here what type of syringes you are using for your Vetsulin, because it is possible to use syringes made for U100 insulin to administer a U40 insulin (but never the other way around!!!!! Lantus etc. should never be given with a Vetsulin U40 syringe) If U40 insulin is being given with a U100 syringe a conversion chart is used which basically means you multiply the desired dose by 2.5 amd measure that amount. If that is the case and you were injecting with a U100 syringe 2.5 Vetsulin then you were really giving just 1U of insulin, so when switching to Lantus you would also give just 1U and fill your U100 syringe to the 1U mark.

Please read the information here on the Lantus group about handeling and storage of the insulin as well as about hometesting, keeping a spreadsheet and the protocol for using Lantus/Levemir in cats. Ask any questions you need to.

 

[Blue]

I switched from Caninsulin (U40) to Lantus (U100) last fall. I took all of my remaining U40 syringes to my vets for others to use. The 2 are different so why cause confusion with conversions and also communication with others on dosing. The cat could end up suffering because of a miscalculation in measuring or misunderstanding of what dose has been given or to give.

We were at 4u Caninsulin when we switched, and started Shadoe at 1u with the proper U100 syringes. Better safe than sorry.

Starting dose for Lantus should be low until you know - what's the saying?
Start low; go slow. I think starting at 1u Lantus with U100 syringe would be safe.

 

[jangell2]

Ok, I was not clear in my post. I was not proposing using u40 syringes for Lantus, I only wanted to come up with a starting dose for Tahoe. Currently I am using u100 syringes with u40 vetsulin. I did that because I think the human syringes are superior to the vet syringes. Years ago we had been using a human insulin and human syringes. The insulin was discontinued and we went to vetsulin with u40 syringes. I and Tahoe immediately felt that the u40 syringes weren't as sharp. So I converted her vetsulin dose into a u100 dose by muliplying by 2.5 and have been using the u100 needles since.

So now I'm trying to determine the equivalent of the vetsulin dose into the Lantus dose using u100 syringes. I know the current u40 dose for Tahoe which is 8.8 u40 units. If my presumption that unit for unit, Lantus is 2.5 times as concentrated as vetsulin, it makes sense to me that I would divide the 8.8 by 2.5 which gives me 3.5 units.

I do realize that this would be just a starting place and perhaps I should even start lower, say 2 or 2.5. I plan on having my vet test her until we get it right. I understand that this is different insulin and the mathematical conversion alone is not sufficient. I just want a starting figure.

I know everyone here does home testing, but I can't even imagine Tahoe tolerating me taking blood from her once or twice a day. She reacts to the needle as it is and bit me badly enough one time that I had to take antibiotics. We have 18 cats (all rescues) in our house and about half are on medication. My schedule does not permit me the time to do testing.

Can you confirm that my calculation is correct?

 

[Monique & Spooky]

There is no mathmatical conversion period. Lantus is not "stronger" (actually it is thought to be "milder" in terms of it's effect on blood glucose levels) it is simply more concentrated in the solution. You say you are giving 8.8 units of U40 Vetsulin...in a U-100 syringe that would mean you are filling the syringe to the 22 unit marking right?

I'm sure someone has told you that is an unusually high dose unless your cat has a condition which makes him/her insulin resistant, or you are feeding a very high carbohydrate diet. In any case if you are currently giving 8.8 units of Vetsulin and this much is required to maintain acceptable glucose control then your starting dose of Lantus should be about the same or slightly less (just to be safe for the first few days) that means you would fill your U-100 syringe which you will be using for Lantus to the 8 unit mark. That would be 8 units of insulin.

I would highly recommend you start hometesting to be sure this is a reasonable dose and to have some information on which to base your potential dose changes later on.

For simplicity sake....You buy coffee powder that comes with a scoop and it says to use 3 scoops per liter of water in your coffee maschine for average strenth coffee. The next bag of coffee you buy also has a scoop with it but it seems much smaller, it also says use 3 scoops per liter of water. In the end the coffee tastes the same (why.....because the second coffee was expresso which is more flavor intense) If you use the small scoop for the first coffee powder you would need to use more scoops than 3 to get the same flavor. In either case you end up with 1 liter of coffee and both taste about the same. Use the right scoop and all is ok!

 

[Iorwen & Tray]

I made the same switch not too long ago and my vet said, because we don't know how the cat will respond to this new insulin we should start slow and low.
I believe you should as well. Pick a low dose and then the good people here will help you find the right dose for your cat.

 

[jangell2]

There is no mathmatical conversion period. Lantus is not "stronger" (actually it is thought to be "milder" in terms of it's effect on blood glucose levels) it is simply more concentrated in the solution. You say you are giving 8.8 units of U40 Vetsulin...in a U-100 syringe that would mean you are filling the syringe to the 22 unit marking right?

yes.

I'm sure someone has told you that is an unusually high dose unless your cat has a condition which makes him/her insulin resistant, or you are feeding a very high carbohydrate diet. In any case if you are currently giving 8.8 units of Vetsulin and this much is required to maintain acceptable glucose control then your starting dose of Lantus should be about the same or slightly less (just to be safe for the first few days) that means you would fill your U-100 syringe which you will be using for Lantus to the 8 unit mark. That would be 8 units of insulin.

She is eating Science Diet W/D.

For simplicity sake....You buy coffee powder that comes with a scoop and it says to use 3 scoops per liter of water in your coffee maschine for average strenth coffee. The next bag of coffee you buy also has a scoop with it but it seems much smaller, it also says use 3 scoops per liter of water. In the end the coffee tastes the same (why.....because the second coffee was expresso which is more flavor intense) If you use the small scoop for the first coffee powder you would need to use more scoops than 3 to get the same flavor. In either case you end up with 1 liter of coffee and both taste about the same. Use the right scoop and all is ok!

Are you saying the u100 syringe is the smaller scoop? And there fore 8 units of Lantus in a u100 syringe is the equivalent of 8 units of vetsulin in a u40 syringe?

I made the same switch not too long ago and my vet said, because we don't know how the cat will respond to this new insulin we should start slow and low. I believe you should as well. Pick a low dose and then the good people here will help you find the right dose for your cat.

This seems to be in contradiction to the previous advice of giving 8 units. In Tahoe's case, with a u40 dose of 8.8, would a Lantus u100 dose of 3 units be a low dose?

From what I've read, Lantus is longer lasting than vetsulin. Perhaps the testing results the vet has taken show the vetsulin wearing off and that is producing results calling for a higher dose.

 

[Shirley and Ragnar]

[quote="
From what I've read, Lantus is longer lasting than vetsulin. Perhaps the testing results the vet has taken show the vetsulin wearing off and that is producing results calling for a higher dose.[/quote]
It's also very possible that your vet is getting higher readings due to "vet stress." Just going to the vet is enough to make a cat's glucose go way, way up. Ragnar's was 70 for about a year after he went OTJ (he's back on insulin since early May and we're still working gradually up to the right dose). But when tested at the vet's, he would show over 200. We had compared my glucometer with their testing equipment using the same blood, and there wasn't a significant difference. His sugar was just going up from the stress of being there and having blood drawn - much harder on him than an ear prick, since they generally took enough to do a complete blood profile to check on his liver, kidneys, check his lipase, etc.

Vetsulin certainly does wear off quickly. We were about to switch Ragnar to Lantus for that reason when he went OTJ, and now we are starting from scratch with Lantus.

Blessings!

 

[Monique & Spooky]

Are you saying the u100 syringe is the smaller scoop? And there fore 8 units of Lantus in a u100 syringe is the equivalent of 8 units of vetsulin in a u40 syringe?

Yup that's it, if you compare the size of the 2 syringes you will see that the U-100 is smaller and thinner, and the scale is also smaller (which is a disadvantage to using these insulins for cats as they require very small doses usually makes it hard to measure) For a human a U100 insulin makes sense If the inslin was (no such thing but imagine ok ) that the insulin was 1:1 so 1 unit per ml water, and you need to inject yourself with 50 units (typical human dose) now you have to squish 50ml of liquid under your skin OUCH! You would have a bubble on your stomache. With a U100 insulin (100 units per ml water) you need just 1/2 ml of liquid that's more comfortable.

Filling the syringe with 8 units of Lantus is giving 8 units of insulin (using the U-100 syringe) while Lantus is a longer acting insulin (in cats between 12-16 hours) it is slower working and therefore causes a milder lowering of the BG. Vetsulin works quickly and "comes on strong" then fades away typically only lasting 8 hours or so in most cats, meaning you have about 4 hours prior to each shot where the cat has no working insulin in his blood. The numbers are often very high at preshot then drop 2-4 hours after injection to almost healthy levels (if the dose is right) then climb back up over the next 6 hours sometimes reaching dangerously high numbers for hours before the next dose. Lantus allows the numbers to stay lower most of the time and more consistant, in addition the serious risks of hypoglycemia are usually less with a slower acting insulin.

As to the dose of 8 units yes it is quite high, even 3 units is atypical (but not unheard of) Most cats find thier maximum dose between 1.5 and 3 units. Some go higher than this 3-5 units) before they show improvement and eventually become stabil on a lower dose. Others never need more than 1 unit or even less. The diet is a factor...If I were diabetic it would greatly influence my insulin needs if I was eating twinkies and potatochips as opposed to brown rice and brussel sprouts.

So I would suggest learning all you can here about diet, insulin, and hometesting.....start testing, maybe someone is in your area here that could meet with you and help you learn? Then read all about Lantus in this forum. When you are ready to start reduce the dose to something we can help you figure out based on your hometesting. Be prepared to test urine for ketones while giving a reduced dose, then get advice from the people here on how to go about adjusting the dose to find what's right for Tahoe.