My daughter was put on bactrim (sulfamethoxazole and trimethoprim) last night for a bladder infection. She has sulfa allergy. Is it ok?

Absolutely NOT!!!! Do not give your daughter bactrim, (sulfamethoxazole and trimethoprim) which is a sulfonamide (sulfa) and could, if she is truly allergic, produce a life-threatening reaction. If she has already taken it and has no reactions, might continue, but if any reactions stop and see the dr. Who prescribed this.