Not sure if this will help anyone or not, but here goes.
In my 30s I experienced unremitting thrush. It did not matter what we threw at it over the course of 2.5 years, it just never went away. Repeated tests for diabetes, all negative. I even followed a restricted diet (no yeast, no sugar) based on an expert book - you'd be surprised what foodstuffs contain yeast, btw!
I was at the Gynaecologist for another matter, and a wee Indian nurse was taking my history. I mentioned how debilitated I was due to unremitting thrush.
She recommended a specific product. It cleared my thrush within a couple of weeks and I was thrush-free for months on end. When I went to purchase more, it had been discontinued. I was devastated and began searching for an equivalent - even spoke with my GP (when I was there on another matter) who said yes it had been discontinued and there was no recommended alternative!
Eventually I found what I use now as a preventative and I have now not had thrush for decades.
Not everyone will respond the same to medications but if you are desperate and can afford it, there would be no harm in trying: Multi-Gyn Acti-Gel.
For me, it has been a sanity-saver because thrush was for me an absolutely debilitating and depressing condition.
Good luck everyone in finding a solution (or gel, or cream, or tablet) that works for you!