At this point it's hard to determine what dose you should reset at - we don't have a clear picture of how the insulin is really working over a 12 hour period. Any test information you have from the very beginning may help with this decision.
Prozinc generally lasts 12 hours in most cats. For this reason I recommend you only dose twice a day. Let's see where the 2.5u you gave him this morning takes him over a 12 hour cycle today. Can you get a couple tests in today please?
I further recommend giving the same dose AM and PM and holding that same dose for a week if following
SLGS (Start Low Go Slow Prozinc dosing protocol) - unless, of course, anytime the BG drops below 90 mg/dL, immediately reduce the dose by 0.25u at the next shot and the clock starts over. We base dose changes on the nadir or how low the current insulin dose takes kitty not on preshot numbers.
It may take (quite) a few cycles for Purna to settle in to these changes and again it doesn't usually happen overnight. Patience is a must!
Insulin & dosing : He gave the appearance of insulin resistance on 2 doses a day, and only started to respond to the 3 times a day, 8-hr dosing.
Without data for us to see what really went on with the 2 doses a day (you'll find we're seriously data driven here!) I wonder if you were actually seeing some Bouncing and/or the possibility of some Glucose Toxicity you mention. Does any of this seem like it describes what was going on:
Definition from the
General Information Sticky
Bouncing
Bouncing is simply a natural reaction to what the cat's system perceives as a BG value that is "too low". "Too low" is relative. If a cat is used to BGs in the 200's, 300's, or higher for a long time, then even a BG that drops to 150 can trigger a "bounce”. It should be noted that “bouncing” is a term we use in the FDMB and might not be recognized elsewhere.
Bouncing can also be triggered if the blood glucose drops too low and/or too fast. The pancreas, then the liver, release glucagon, glycogen and counter-regulatory hormones. The end result is a dumping of "sugar" into the bloodstream to save the cat from going hypoglycemic from a perceived low. The action is often referred to as "liver panic" or "panicky liver". *Usually*, a bounce will clear kitty's system within 3 days (6 cycles). You cannot avoid all bouncing. It is normal and natural, and frustrating. There are some things to keep in mind that can help though:
- Following a bounce, a cat’s BG may stay high and flat for several cycles. Avoid the temptation to increase the dose at this point. If the BG does not return to normal in 6-8 cycles, an increase might be needed based on the method of regulation you are following.
- Some vets might have little/no understanding of the bouncing phenomenon. Consequently they will look at a single BG number or a single in-office curve and change the dose without realizing that they could be looking at a bounce number, or a high-flat cycle following a bounce, and increasing the dose will make it worse.
- There is also a common misconception, often by vets, that bouncing is caused by chronic Somogyi rebound. Michael Somogyi published one paper based on a very small number of human diabetic subjects on the topic in 1938 in a local St. Louis medical journal. There has been no replication of the research and, in fact, anyone that has attempted to replicate the research with humans failed to find similar results. The research has never been done with cats and, just as importantly, has never been done with cats (or humans) using a long-acting insulin.
- When it’s not a bounce: in general, during a cycle, the blood glucose should decrease for a few hours, and then begin to increase again. If you plot the numbers on a graph, they should look like a smile. This rise in BG towards the end of the cycle is normal. It is not bouncing. As a cat gets better regulated, the cycle will get a little flatter and the PS numbers will decrease, but in the beginning, it can feel like that rise at the end is a bounce. It often isn’t. It’s just the insulin losing duration. As you slowly reach a better dose for your cat, the insulin will last longer and the numbers will look better.
How we deal with Glucose Toxicity:
From the
New to the Group, the Prozinc Basics, Sticky, excerpt from subsection
INSULIN RESISTANCE/ GLUCOSE TOXICITY: Worth knowing about:
"This is how we use this concept on the forum: If your cat has been on PZ for quite a while, remaining in “high and flat” BG numbers throughout his/ her 12-hour cycles at the current dose, the dose may need to be increased every 6 cycles by a small amount, until you reach what we call a “breakthrough” dose."