Someone else will come along and possibly share their experiences with it. I have no first hand experience with it myself, but there is nothing wrong with getting a 2nd or 3rd opinion from other doctors. Especially see if your nephrologist & rheumatologist have talked with each other about it. Maybe use your pcp as the "mediator". I do know that whatever med you use, your doc will do regular blood work to follow the progress, and watch for signs of trouble, and call for other meds if necessary. You'll have to weigh the risks versus the benefits, and that can be tough to do. Be sure and write things down as you think of them, so that you can ask your docs questions next visit. I used to write down their answers 'cause I couldn't remember them by the time I walked out the door, but now they've got a new computer system, and they print me out a report each visit, which is much easier.
btw, welcome to the forum!
"There but for the grace of God, go I."
"... His mercy endureth for ever."