Manal-
Sulfa (I think this is what you mean) is usually part of a sulfonamide based antibacterial agent. It can cause hemolysis and can induce very serious allergic reactions in many people. It is generally avoided unless you don't have a history of blood disorders or allergic reactions. Its not REALLY an antibiotic, but it works in the same way. It also blocks folate - so definitely a stay away for thals!