I have had sciatica on and off, BOO, and the last bad bout lasted for about six months. It was eventually helped by a physiotherapist on the NHS and with ultrasound, although it still twinges.
However, it was no way as bad as your daughters and I had complete bladder control. One of the first things doctors usually ask is whether you are having bladder or bowel problems. Please, please get the doctor in for her. Obviously the pills aren't having any effect.