Hi there,
Once again, I'm very sorry I couldn't stay to help last night but you were in very good hands with Bron.
I'm so glad that you found FDMB. I'm also very glad that you followed your good instincts and gave Molly extra food yesterday. (She has the loveliest little face, BTW.

)
As the others have said above, 6IU - of
any insulin - is a
massive starting dose, even when a cat is in high numbers at time of diagnosis. (Note: IU = International Units.)
The
most recent manufacturer guidelines for Vetsulin (branded as Caninsulin in some countries outside the US) give a maximum starting dose of 2IU twice daily
per cat - regardless of its weight - if the baseline BG level at time of diagnosis is 360mg/dL or higher:
General note: Starting dose for dogs is based on weight, and they are typically given one dose of insulin per day. Cats have faster metabolisms than dogs which means that insulins have a much shorter duration of effect, hence the need to give them two insulin doses per day, 12 hours apart. An older version of the manufacturer's dosing protocol used to take a cat's weight and baseline BG level into account when determining a starting dose, but even so the maximum starting dose was still set at 2IU twice a day.
Here's an example of an 'ideal' response in a feline diabetic to Vetsulin/Caninsulin:
As you can see from the blue line, Vetsulin hits very hard and fast early in the 12-hour cycle, BG (red line) then typically drops quickly and steeply in response (hence the need to get grub on board a little while before administering the insulin dose). The effect of a Vetsulin dose typically peters out around +8 hours after dose administration. That said, if too high a dose was given then there was a possibility that BG might stay in a lower range for longer until the dose wears off completely (hence Bron's advice last night to keep feeding Molly snacks until you reached the time when 12 hours had elapsed after the dose was given.
Here's a link to a copy of the latest
AAHA guidelines for management of diabetes in cats and dogs (from 2018).
From the linked document:
The initial approach to management of the diabetic cat is to initiate insulin therapy with glargine (Lantus) or protamine zinc insulin (PZI; Prozinc) at a starting dose of 1–2 units (U) per cat q12 hr.
Both Lantus and Prozinc typically have a gentler mode of action and a longer duration of effect in cats, hence their recommendation by the AAHA. (NB: Lantus is expensive in the States so many of our members get a prescription from their vet and buy it much cheaper from Canada. We can give you details of how and where to buy if you need them. Also, I
think chewy.com do a good price on Prozinc. I think they also need a veterinary prescription when placing an order.)
I hope the above information will be helpful to you in your discussions with the vet. Please give a shout out with any questions you have - there's a lot to get one's head around in the early days. Again, I'm glad your instincts were so good yesterday and that you found FDMB. We'll do all we can to help you both as you learn to manage Molly's diabetes.
How is Molly doing today? (((Molly)))
Mogs
.