I might have a different take that others on Prozinc vs. Lantus, but I have a couple observations....
First off, I don't know how my cat, Bob, would have done on Lantus. I used compounded PZI which he was on for 10 weeks or so, then he went OTJ. So of course, my opinion, specific to Bob, is that it worked really well for him. :smile:
Specific to what others have said here:
ProZinc is shot based on the preshot #s, and not the nadirs.
Lantus is handled very differently than Prozinc. The dosing is based on the nadir instead of the current bg.
Part of the problem is the misconception that Prozinc dosing is based just on preshot numbers. It isn't. At least, it is not as effective if that is the way you or your vet sets the dose. Lantus dosing IS based on the nadir reading. But the more effective way to figure out dosing with Prozinc is a combination of the preshot numbers AND the nadir numbers. Looking at only the preshots tells you nothing, and that it one reason why some cats don't respond to it well. If you do not know what the mid-cycle numbers look like, then you have zero idea of what a dose,
any dose, is doing. That's one reason why vets continue to advise upping the dose. They think that if the preshots remain high, the dose is too low. That is no different than using Lantus, and not testing in the middle of the cycle, which is insane to attempt.
The low point of the cycle is the indicator of a dose needing to be increased or decreased. Just like with Lantus, the continued presence of high preshot numbers can be due primarily to the cat "bouncing" off the low mid-cycle numbers. Not paying attention to mid-cycle numbers with ANY insulin is an unsafe way to treat the illness. And not using those mid-cycle numbers to evaluate the effectiveness of a dose is a tragedy waiting to happen. Prozinc should never be dosed by just the preshot numbers. It is not safe, and can lead people to mistakenly conclude that the insulin isn't working for their cat.
You have a lot more control with Lantus than you do with Prozinc in guiding the numbers.
I'm not sure I understand that statement, but on the surface, I don't think I agree with it. You can steer the numbers with
any insulin using food, carb counts, and meal timing. Lantus, I think, gives you less flexibility, because you need to hold a dose for X amount of cycles, and you need to dose as close to exactly 12 hours apart for it to be most effective. Prozinc actually gives you more flexibility, both on timing, and on dose amounts on a cycle by cycle basis. The key, no matter what type of insulin you are going to use, is to collect sufficient data so that you can make informed and logical decisions based on the data. That requires frequent testing, and testing "in the middle" of both the AM and the PM cycles when possible. Every cat is going to respond to every insulin differently, and what works for one cat may or may not work for another cat.
The best way I have ever seen the "which insulin is best" question answered is this -
There is no such thing as a "best insulin". The "best insulin" is the one that works best for YOUR cat.
All that said -
When I look at Lily's SS, it does not look like she has responded well to the 3u dose of Prozinc. You see very little "curve" on the majority of her cycles. No big drop in the middle. However, I don't know if that is due to the dose (meaning I don't know if "more" or "less" is the correct answer), or to the insulin type. When you see her go from pink preshots, to blue preshots, with no tests in between, there's no way of knowing if the dose is too low or too high. My hunch is that it is "too high", and what you are getting is really low numbers in the middle that you aren't seeing on the meter, or you are getting a really late nadir (which can indicate a dose is too high). Then other days, you see a pink number, and very little drop at nadir, and then right back up to pink preshots. That looks like a dose that is doing nothing for her. 10/21 is a perfect example. Just looking at that one cycle, 3u did nothing for her. BUT, you can't make a dose decision based on just one cycle, with any insulin. At best, your data is inconclusive.
Two final points -
- No matter whether you keep her on Prozinc, or switch to Lantus, you need more data. You don't have any data that shows what is happening between her PM shot and her AM shot. Most cats won't have AM cycles that match the PM cycles, so in order to really know what a dose is doing, you need PM spot checks, and random checks that aren't preshot numbers or nadir numbers. Right now, you can't say for sure when her nadir is on Prozinc.
- I would advise a switch to Lantus, personally. And the primary reason would be the TR protocol, not necessarily that I think Prozinc won't work. There is no official protocol for Prozinc. The Lantus protocol is science based, logical, and well documented. It offers you a set of guidelines to follow that have been proven to work, with thousands of cats. It takes most of the "guesswork" out of the picture. Yes, ECID, and your cat may not follow the rulebook. But at least using a protocol helps you understand what to do based on data and other peoples' successes.
3u isn't a "high" dose, but it is a dose that is higher than normal. My cat went as high as 4u BID before he started to get better. From what I've seen here since I joined, that's more insulin than most cats ever need. It's totally possible that Lily
will need more than 3u, with Prozinc or Lantus, but she might also need less than that.
If you do decide to switch, please make sure that your vet is aware of the Lantus protocol and dosing information that people have linked you to. They have to at least understand it, even if they have more experience with Prozinc, and switching is something that you want your vet to be supportive of (even if you don't need to rely on their advice for dosing in the future) if you want or need their support.
Carl
