My quad-pug Tani had terrible arthritis in her back and all four legs, it was first diagnosed at 6 years old.

We started with supplements and ramped up over the years to include prescription meds.

If I remember for Tani once we started the loading phase of adequan (once weekly shot for four weeks, then monthly for maintanence) it was about week three that we saw improvement.

Based on what you posted you have room for more meds and supplements.

Here is what Tani was on:

Fish oil, twice daily in meals

glucosamine, max dose for her size, one time a day

rimadyl, max dose for her size, 2 times a day with meals (note- this is an anti-inflammatory med,  it does provide some pain relief but there are stronger pain meds)

gabapentin, a pain med, 2 times a day with meals

adequan injections, after loading phase 1 time a month at first, increased to every two weeks.

With all those meds regular blood work was important.

I also found that chiropractic treatments really helped Tani.  You might also try acupuncture.  And the amount of exercise Tani got was important for her mobility.  She tended to over-do so I found I had to regulate her activity so she wouldn't get so sore.

I hope you find a good balance for Lexie.

Karen and the Spirit Pug Girls