I too am RA negative arthritis, have been on MTX for years. after some time it was found that I do not take up MTX via my stomach, as I was getting no relief at all, and that's unusual, so changed me over to self injecting into upper leg once a week, I nearly freaked, Dr put me in my place with the words, their are 8 - 9 year old children who are self injecting insulin, get over it, she was right, just the thought of sticking myself with a needle, UGHHHH, I still am a little needle phobic but no where as bad as I was, you can get over it, very patient GP helped me the first few weeks to self inject.
Arava, which does not like me at all, night sweats, loose bowels, take it at night, and in the morning the family know to stay away from the toilet, it is mine, (known side effect) and that's on 10mg, 20mg dose I developed extremely high blood pressure, apparently only about 2% of patients have this side effect, I can manage to take it just by taking every 2nd day at 10mg dose, really does help settle arthiritis, so worth the problems.
Don't know about the others, but I'm sure someone else can help.
​What I will say as a last comment, have you tried stopping eating ALL WHEAT, a few months ago, I just got sick of all the tablets, and the side effects, as above, and one day just stopped eating wheat, I check everything's labels, some are naughty and don't even put it on labels, if under 2% apparently they don't have to, and guess what, the pain lessoned.
I don't find it easy, as I love a bit of toast, have been sticking with fruit, rice products, cornflakes for breakfast, surprising enough I can eat oats, they don't seem to cause me problems, have even given up potato as well, the difference it has made is astounding, so do I have a problem with wheat, nothing the Dr has tested me for comes back with a positive result.
I could feel the difference in pain levels within about 4 hours, and thought it can't be this easy.
Is it worth a try, YES, and can it do you any real harm NO.