Darrah --
The last time Girlie had a run of black numbers was at the end of August. Was there anything other than increasing the dose back up to 0.75u that you can think of that contributed to the earlier run of high numbers? While the Flixotide shouldn't have a huge effect on numbers, it's still a steroid and some cats may be effected by an inhaled steroid.
The current numbers may simply be that Girlie can't sustain the current dose. Some kitties' numbers go up and down whether it's because of something like constipation or the stage of the moon (seriously!).
FWIW, I was reading up on the Zydax. While it's primarily used with dogs, it is used off-label in cats. The dosing is generally once a week for 4 weeks. I don't know if you're going to see much improvement in Girlie's arthritis the way your vet is administering it.
@Sienne and Gabby (GA) : I just transferred your post here so it would be in today's post and I wouldn't have two posts running concurrently and confuse everybody.
Yes, you're right: end of August when she also had Zydax but wasn't constipated - does that rule out the constipation factor? Also, with that insulin cartridge, I did everything that you could do wrong when drawing insulin; not sure whether that was a factor for the high run of blacks there, but started and new insulin cartridge and increased the dose, and she came down.
The only things that happened after 10/10 were:
- 6 Oct: started using insulin ruler to measure dose on 1/2 unit BD 0.3 syringes: clear from that that just eyeballing the dose based on syringe lines resulted in very different doses per syringe compared to insulin ruler
- Vet checkup 10 Oct: blood and urine draw and Zydax injection; her last blood draw on 21 Aug didn't change her numbers at all: stayed in blues
- Constipation: Microlax enema at home (easy and no adverse reaction after - just lots of poo w/no straining or pukas)
- BCS reduction to 0.1 on pm of 10/10 and AM of 11 Oct (panicked at being away all day after the 83 on 10/10 and signs from her that she wanted to dive down); she was already at 504 on 10/10 for her PMPS, though. Previously, she came down pretty quickly after a BCS and even a NS. Could the depot have drained from just those two reductions?
- Test results: only big thing was the increase in creatinine to 290 (was 190 end of July). Will do another check on this next month. Haven't entered all results in Lab section of SS yet; will do soon.
Zydax: Started in 2013 for arthritis; originally got 1x shot/week for four weeks; last year switched to 1x/month to see if that would maintain her better.
@Bron and Sheba used Cartrophen (as did Wendy and Neko, I think?), which is also Pentosan (like Zydax), but they had no adverse BG reactions. I can try Zydax again next month to see the reaction, or I can ask the vet about trying Cartrophen instead? In Australia, there are meds that you can get in the US that we can't here, and vice versa. Meloxicam is another example: I believe we use a different concentration here specifically for cats and that's why we don't have the black box warning that you get in the US. However, I stopped the Meloxicam a while ago due to her kidney issues.
Flixotide: I've been using this all along, so I don't know whether this can figure in?
If it's the stage of the moon, or that she wants a set of pearls to go with her new black dress, Girlie is going to get a stern talking to!
Some poo overnight. 
I am way too tired to be able to make this decision!
even if he isn't hungry.