Yes, I am on 20 mg of mtx and take leukovorin 24 hrs after the mtx. It is a folic acid that is supposed to prevent the continued absorbtion of the mtx into the system which could be potentially harmful to the "good" cells in the body. The mtx reaches it's maximum efficacy in the first 12-24 hrs after ingestion, so the folic/leukovorin is kind of like a reversal/rescue drug of sorts. I don't have a lupus dx but a lupus-like Connective Tissue Disease. The mtx worked well for me in the first 3 months but it's not been able to get me into remission. My rheumy is battling my insurance co to also get me on Enbrel injections along with the mtx right now.
I don't get nauseous on the mtx any longer and it was only very minor to begin with (been on it since Jan.07) but I'd hate to think how badly I'd feel without the mtx. Plaquenil wasn't helpful in my situation. I'm still on 10 mg of prednisone and it's my saving grace along with celebrex.
I had some minor hair loss with my illness even before I started any meds and that hasn't changed even with the mtx - I'm still sort of "shedding" - but I had a lot of hair to begin with
Good luck to you.