Looking at your spreadsheet, I don't advise shooting at 100, or at anything under 150 for that matter.
What type of meter are you using? On a pet glucometer, normal BG range is about 70-150. On a human meter, we usually consider 40-120 to be the normal BG range. So if your vet is advising that you shoot anything under 120 (or 150), she's telling you to give insulin to a cat that has normal blood glucose numbers. Why would she want you to do that?
Yes, when you feed, the BG will go up some, and the insulin will work to lower it. That's how a healthy pancreas works as well. If your cat was not diabetic, and you tested his BG before and after feeding, you would see the BG go up, then back down as his pancreas did the job nature intended it to do. While your shot is taking the place of the insulin his pancreas should be producing, the problem is that you can't give just the right amount, like his pancreas would. Even if you halve the dose, it might be too much, especially if his pancreas is trying to produce some insulin of its own.
Larry said that he shot 2.5u of Lantus on a PS of 118? Well, that's fine for Larry, he's been doing this for years. And Larry is using Lantus, which doesn't work the same way that Prozinc does. Lantus dosing is not based on the AMPS or PMPS number, but on the nadir number that happens between shots. Many Lantus users give shots on numbers of 100 or even less. But again, that's the way that insulin works. Prozinc doesn't work the same way, so you can't follow the same "rules" that Lantus users follow without putting your cat in danger.
Question - are the doses you have been giving based on a scale the vet gave you to use where you adjust the amount based on the number at shot time?
If you look at June 3rd, when you shot 2u on a 441.... The BG dropped 350 points or so. Then you shot the same dose on a 287 that night. Without tests in the middle, you can't know how low it went. But the next morning it was only 108, and you skipped the shot. That was exactly the right thing to do. But what it indicates is that 2u on a 287 was too much. The cycle went more than 12 hours, indicating too much insulin. The next night, the number was higher than you wanted it to be I'm sure, after 24 hours with no insulin. But you shot a bit less with 1.75 on a 388, which logically sounds good. But the next morning, you again got a number that was on the borderline of "shoot or don't shoot", so you skipped, and got that ugly black number after 18 hours without insulin. What I find interesting is that it didn't continue to climb for the next six hours like you would logically expect, right? Instead, it dropped about 100 points. That would seem to indicate that he's at least producing some insulin on his own.
What you should try for is to find a dose high enough to keep the numbers under 300 or 250, but low enough to give you a number that you are able to safely shoot insulin into every 12 hours. To me, your spreadsheet indicates that in general, the doses have been too high so far. They are either leaving you with a low number 12 hours later, or they are causing the dose to last longer than 12 hours. Either way, you haven't been able to consistently dose twice a day due to low numbers.
You can draw a line in the sand at 200, or at 150, but you need to find a low enough dose to get those numbers at least by shot time.
Insulin isn't perfect, it doesn't act the same way every shot, and it doesn't follow a proportional logic or a ratio. You can't say "OK, 1.5 dropped it 250 points, so .75 should drop it 125 points." You can think that, but there are no certainties when it comes to how much insulin will be the exact right amount to shoot.
1.5 units might drop the BG 200 points today, and drop it 150 or 250 points tonight. With some of the mid-cycle numbers you have seen (the nice pretty green ones), you don't have much wiggle room between how low they were, and "too low".
I used PZI, which acts the same way Prozinc does, but doesn't last quite as long. Like Larry, I also shot "normal" doses into "normal" BG numbers. I shot 1u or more into numbers in the range of 90-110. BUT, I wasn't using Lantus, I was using a "P" insulin, which works differently. So I was stupid to do that. I could have killed my cat. In my defense, I wasn't aware of the fact that what I was doing was dangerous, or potentially fatal. My vet told me "call me if his number is less than 100". Otherwise, she said to "shoot the scale". She laid out a scale of doses that were graduated based on Bob's BG test numbers, and I blindly followed her advice. I did that for about 6 weeks or so, then realized the danger in doing that, so I decided to no longer follow her dose advice, and started reducing on my own, based a lot on what I read here. The people here, (while I never really asked for any dosing advice from them), saved Bob's life as far as I'm concerned. Just reading what they said to other people made me rethink what I was doing. I don't have any doubt that if I had not found FDMB, Bob would have died from hypoglycemia . Instead, 4 weeks after I started to reduce his dose and treat him more safely, he went into remission.
Bottom line....you hold the needle, so it's always your call on what to shoot and when. What you'll find here is that everyone's primary concern is the safety of your sugarkitty. So we advise cautiously. That's where the "200 line" comes from. Until you have a lot of data, so you more or less know what will happen based on the dose and the BG number you see at shot time, you should always err on the side of caution. Once you shoot the insulin in, you can't get it back out.
I would reduce the dose to 1u, test before every shot and at least once around the +5 to +7 range every cycle. On a day off, test 3 or more times between shots so you can see what the insulin does over 12 hours. Stick with that dose for 3 or 4 days, record all the data, and you would hope to see patterns start to show on the spreadsheet that will tell you whether the dose is too low, too high, or just right. Then you can adjust accordingly. Of course, if you see a really low number in that time period, you'd think about reducing the dose accordingly. If you have questions, ask away. People are here all day and all night to help.
Carl
