I would increase him by 0.5u. I'm suggesting this based upon the
and the option of increasing after 2 days if you have continuous high nadirs. I've highlighted the relevant part below. That's the same protocol as ours, but it has a few things worded differently - this being one of them.
Most cats need to have their dose increased. Do it in 0.25 IU or 0.5 IU steps (0.25 IU if the cat is getting a low dose and/or relatively low BGs, 0.5 IU if the cat is getting a higher dose and/or relatively high BGs). Hold each dose for 5-7 days.
However, if the cat is producing continuously high BGs (nadir always >=300 mg/dl), only hold the dose for 2-3 days before increasing it by 0.5 IU.
Alternatively, if the cat is continuously producing moderately elevated BGs (nadir always >=200 mg/dl), increase the dose every 2-3 days by 0.25 IU ( if the cat is getting a low dose) or 0.5 IU (if the cat is getting a higher dose). From this point onward test for ketones once per week, or more often if the nadirs are still >=200 mg/dl.
Many cats will occasionally react to an increased dose with increased BGs - within the first 2 to 3 days after an increase, usually lasting for less than 24 hours. Nobody really knows what the reason for this phenomenon is (perhaps a "panicky liver"?) - hold the dose and ignore the fluctuations.
It is likely, because of the way Lantus and Levemir work (they appear to work for >12 hours, therefore producing overlap between doses), you will face the problem of having a low pre-shot BG and wondering what dose you should give. Try reducing the dose the first few times to see what happens - in all likelihood the cat will have higher BGs as a result. A second alternative is to feed the cat, wait 1 to 2 hours, test again, and when the BGs start rising, give the normal dose. A third alternative is to split the dose: feed the cat, give most of the dose immediately and give the remainder 1 to 2 hours later when the BGs start rising. However, in most cats none of these alternatives have shown themselves to work as well as consistent dosing. You will have to learn how your cat reacts to Lantus/Levemir before you determine the best way to deal with this problem.
Try to find a way to dose as consistently as possible, time-wise and dose-wise: sliding scales don't work. Don't skip shots. Fluctuations are very common in this phase before BGs start to stabilize under
consistent dosing: a typical curve of cat over the first 1.5 months on Lantus can be seen
here.
When the cat first begins to have daily nadirs in the normal range of a healthy cat (50 to 80 mg/dl) and spends significant amounts of time in this range each day, stop increasing the dose and switch to Phase 3. It doesn't matter
when you measure these lower BGs, it can be at pre-shot or sometime between shots. Getting to this point generally takes 1 month, sometimes a lot longer. Cats are extremely variable in terms of the maximum dose they end up requiring: they have ranged from 0.5 IU to 10.0 IU BID in the German forum, with most cats lying between 1.0 IU and 5.0 IU BID.
Be aware that experimental studies in human diabetics over the last 15-20 have rejected the existence of the Somogyi effect (sometimes also called rebound). In cats, no studies have ever been done which properly demonstrate that such a phenomenon exists. Therefore, adjust the dose as described above, focusing on the nadir: don't do so-called rebound checks, as they only lead to unnecessary (and unhealthy!) hyperglycemia.
and then we got the black. Yes, I presumed it was cos he is used to high numbers.