2/27 GracieD AMPS 146 - How does Lantus/insulin work?

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Jason & Belle (GA)

Jason & Belle (GA)

Member Since 2010
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Good Morning! Something is happening with Gracie.

So yesterday I was frustrated at her high PS numbers, and last night and this morning, we have the lowest AMPS/PMPS ever. Something has definitely shifted, as her midcycle numbers have been getting progressively better. Too soon to know if the bounces will stop, but it's progress. Now though, we have other concerns. With her huge drops come concerns about dosing at lower numbers. I was tempted to shoot 1u this morning, but thought better of it and shot .75u. I'm just not sure what will happen, even at .75. The last time she was this low PS, I shot .5 and her +1 went to over 400. We'll see if things really have changed.(Her +1 was 239 today)

This leads me to a question. Does insulin affect the body differently based on the BG levels? If 1.25 could drop her BG's over 250 points from a 507 PS can it do the same at a 200 PS or is the drop more based on percentages? Meaning 500 with a drop of 250 is 50%. Would 1.25 at a 200PS also drop it 50% to 100? This will help me decide on dosages as her AMPS yesterday was 507 and today it's 147. At 1.25u, that 147 she's at today would drop to 0 in an hour.

Thanks, Jason
 
First, you need to adjust how you are conceptualizing dose decisions. Lantus dosing is not based on a pre-shot number. As a long-acting insulin that is a depot-type drug, dose is based on the nadir. You do not always see an immediate response to a change in dose. The effect may be seen in one or two cycles due to the influence of the shed (i.e., the depot). Reducing Gracie's dose based on her AMPS, or any pre-shot number, means that you will be giving inconsistent amounts of insulin at each shot and as a result, numbers will be far less good. Short or intermediate acting insulin dosing is based on the pre-shot numbers. This is just not the case for Lantus or Lev. Likewise, by reducing the dose this morning, like the last time you reduced based on pre-shot, you gave a lowered dose which is likely to have less of an effect on the currently rising numbers and because the shed is emptying, by this evening, numbers will still continue to be high. Of course, safety is a consideration but all things being equal, probably stalling 30 min. would have told you that numbers were heading up. (Also, for future reference, don't feed if you're stalling.)

If you read the Tilly Protocol, there is a statement about Lantus/Lev potency. These are not "potent" insulins. In other words, these insulins are not used to their best effect to try to drive numbers down the way Humulin N or PZI can do. Instead, Lantus/Lev are gentle, long-acting types of insulin. As numbers come down, it is easier for Lantus/Lev to "grab on" and cause the curve to be characteristically flat. For example, take a look at Mocha's SS. This is a cat that is moving (or has moved) into tight regulation. The numbers have flattened out and the bounces are gone.

Take a look at Libby's post on handling low pre-shot numbers. It will also give you some guidelines.
 
Thanks Sienne. I do understand all of that, and her numbers have bounced quite a bit today. I did however take a second BG about 25 minutes after the first, immediately after feeding,, and it was down to 146 from 156(I know meters aren't that exact). If the number was higher, I would have assumed she was going up. I also know that nadirs are the guide here. That said, when her PS is lower than her nadir, that concerns me. If she had a drop anywhere near typical for her, she'd be in hypo within an hour or two. Maybe I need to be ready for her to get over the bounces and have a steady cycle, with low PS's, but it's still tough to shoot when the numbers scare the heck out of you. That's why I asked how it actually works. If the dose is tied to the nadir, then theoretically once you establish that nadir, any preshot number should be safe to shoot since the Lantus will drop you no lower than that nadir. When the PS is lower/marginally higher than the nadir, a flat curve should set in.

As for the shooting low numbers guidelines, I actually gave her a higher dose than the general guidelines recommend. I didn't take the third option because after waiting 1/2 hour and feeding, her numbers didn't rise and I didn't want to wait longer or skip a shot. Next time this happens, and I'll be home with her, I'll stay the course and test like crazy.

Thanks for the input. Although I had Belle on Lantus for 6 months and do understand the basics, this has been a different experience.

Jason




Sienne and Gabby said:
First, you need to adjust how you are conceptualizing dose decisions. Lantus dosing is not based on a pre-shot number. As a long-acting insulin that is a depot-type drug, dose is based on the nadir. You do not always see an immediate response to a change in dose. The effect may be seen in one or two cycles due to the influence of the shed (i.e., the depot). Reducing Gracie's dose based on her AMPS, or any pre-shot number, means that you will be giving inconsistent amounts of insulin at each shot and as a result, numbers will be far less good. Short or intermediate acting insulin dosing is based on the pre-shot numbers. This is just not the case for Lantus or Lev. Likewise, by reducing the dose this morning, like the last time you reduced based on pre-shot, you gave a lowered dose which is likely to have less of an effect on the currently rising numbers and because the shed is emptying, by this evening, numbers will still continue to be high. Of course, safety is a consideration but all things being equal, probably stalling 30 min. would have told you that numbers were heading up. (Also, for future reference, don't feed if you're stalling.)

If you read the Tilly Protocol, there is a statement about Lantus/Lev potency. These are not "potent" insulins. In other words, these insulins are not used to their best effect to try to drive numbers down the way Humulin N or PZI can do. Instead, Lantus/Lev are gentle, long-acting types of insulin. As numbers come down, it is easier for Lantus/Lev to "grab on" and cause the curve to be characteristically flat. For example, take a look at Mocha's SS. This is a cat that is moving (or has moved) into tight regulation. The numbers have flattened out and the bounces are gone.

Take a look at Libby's post on handling low pre-shot numbers. It will also give you some guidelines.
Click to expand...
 
Every cat IS different and you are clearly seeing differences between Belle and Gracie.

I honestly wouldn't get all wrapped up in whether the pre-shot from one cycle is lower than the nadir. Until you have a cat regulated, each cycle can be very different. With a lower than usual pre-shot, I'd be more attentive to whether you have a dropping number. If you do, it doesn't necessarily mean that you shouldn't shoot (although it depends on what the number is), it does means you will need to be testing and be sure where the numbers are heading.

There are also some cats who have late nadirs. For those cats, you have to envision shifting their entire pattern by 6 hours. Compared to a cat with a mid-cycle nadir, these cats are low at pre-shot and higher at mid-cycle. Also, remember that the nadir is not a static point. It can change from cycle to cycle and it is not always at +6. Gabby tends to have an earlier nadir -- but not always.
 
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