First, welcome to the group!
It looks like Prozinc wasn't awful but more that you weren't getting sufficient duration.
Chances are that if you start dosing with Lantus over a weekend, you won't be "set." Because Lantus is a depot-type of insulin, it takes approximately 5 - 7 days for the depot to form and stabilize. You may not see a great deal of response until the depot settles down.
Changing over: Generally, you can make a direct change in dose. You don't need to wait for Prozinc to clear out of your cat's system and you can start at your current dose. If you're feeling apprehensive about starting at 1.25u, then start at 1.0u. One thought, given your schedule, is to start at a dose of 1.0u and start earlier in the week -- Tues. or Wed. -- so once the depot has built up, you will be home over the weekend to monitor.
I'm not entirely sure I know what you mean by,
"How do I start?" I'm going to interpret that in terms of which dosing approach to use. You have 2 choices -- the Tight Regulation Protocol (TR) or Start Low Go Slow (SLGS). Each has it's pros and cons. TR requires more testing and is a more aggressive approach. You are testing enough to use TR. With TR your cat must be on a low carb, canned food diet only. TR also has the advantage of having its basis in published research and has a strong track record for getting cats into remission. SLGS pre-dated TR and is the approach that has been used here not just for Lantus but for other insulin as well. Dose increased are made weekly (vs every 3 days with TR) and the threshold for when you reduce is different.
Purchasing insulin: Both Lantus and Levemir are human insulins so if you want to spend big bucks, you can purchase them at any pharmacy. Because they are human medications, vets don't stock them. Many people here purchase their insulin from Mark's Marine Pharmacy in Vancouver. The savings on the cost of Lantus is substantial. I'm tagging one of our members who knows more about using Mark's than I (
@Chris & China (GA)). I used Lantus throughout Gabby's life. There are pharmacological differences between Lantus and Lev and I'm happy to go into the differences if you'd like. However, the important way that they differ is when their onset and nadir occur. With Lantus, onset is at around +2 and nadir at around +6 versus with Lev, everything is about 2 hrs later. (These times are approximate because some cats' onset and nadirs are typically early or late.) I stuck with Lantus because of my work schedule -- I could get several tests in before I left for work because Gabby had an early nadir and those tests let me know if her numbers were dropping. If I'd been using Lev, I would not have had benefit of that information.
Sticky notes: Read them all!! Start with the New to the Group and read up on the two different dosing methods and the sticky regarding the insulin depot.
Syringes: Please make sure your vet gave you an Rx for syringes. You will need U100 syringes for Lantus or Lev. It's helpful to have syringes that are marked in half unit increments.
And please ask questions. People here are very generous with their time and knowledge.
