Am seeking a prescription for this right now. Came up with a plan over the winter for my OTTB, and Pentosan next on the list.
First was finally finding a good barn (on #3 after a year and a half), and he is in a training program ridden regularly by our dressage trainer and myself. Ultimate job unknown - I’m old H/J, last barn’s visiting trainer was eventing, but just want this guy to be able to do well in whatever looks right. Current trainer wonderful in identifying issues and knowing solutions.
This winter I searched just the COTH forums, and there was so much positive about Pentosan, thought I’d include it if it was apparent he needs more. When we moved to this new place, I had just started him on Cortaflx, but being a 10yo OTTB who had raced 4 years (and has taken some time for him to get in the right frame of mind - right barn helps!), I thought I may have to move up to the next step.
He is just now really learning to carry himself properly, we are getting him centered and away from bowing out to one side or the other. The Cortaflx is good, but he has an arthritic L ankle, and is “hocky” and can still take some time warming up to get comfortable and move well underneath himself. Also diagnosed with kissing spine, but hasn’t seemed to have an obvious back issue once we had the right saddle. Trainer agrees starting on Pentosan is a good next step.
Have never done injections of any kind. Left message for general vet for new barn and he hasn’t returned my call. Left barn that my favorite lameness vet visits, but have kept in touch with her. Called tonight and it’s been over a year since she’s seen him, so she can’t prescribe, but also wasn’t high on Pentosan
, although with Adequan not being available, would have written the script. As I’d read here, thought the Pentosan would be a good first option since it doesn’t just address one area. Will try general vet again - at least Wedgewood has his name on file, so hoping he’s just busy. And trainer has another vet in mind just in case.
I just thought it would be easier calling to get this prescribed. Reading the posts on COTH isn’t exactly scientifically based, but I even created a chart of what seemed popular, and was sold on Pentosan being the next logical option. 
Will add our 2 cents when we can get going!