There aren't "other drugs similar to plaquenil" - it is known to inhibit disease progression and honestly we can't generally tell if it's doing anything unless we stop taking it and the disease gets worse. This is not recommended.
I suspect you meant "other drugs similar to prednisone" - this is the steroid often used to combat inflammation and thus indirectly treat pain. Medications such as Cellcept, Imuran, and MTX are used instead, they don't have the side effects on calcium (bones) and sugar (weight gain) that Prednisone has.
It is unknown why one of these 3 (Cellcept, Imuran, and MTX) help, and the only way to tell which one will help a specific person is to try it and see. I tried Imuran, no side effects but no help either. Then I tried Cellcept (again no side effects) which has been my miracle drug and changed life from one long flare into something almost equal to my pre-Lupus condition. I think MTX has the most side effects thus my choice to save it to last in case neither Cellcept or Imuran worked.
If your Dr really said "other drugs similar to Plaquenil", I would find a Dr more up-to-date on Lupus. I suggest checking with the Lupus Org at www.lupus.org to find your local chapter of the organization. Then check in with the local chapter to see which local Drs are active on the advisory board -- these are generally the Drs most interested in and most experienced with Lupus in your area.
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2000DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde