I Am To Have A Urea Breath Test Early Next

I am to have a Urea breath test early next week and have recently taken Colofac and am not sure if it is an antibiotic, which apparently I shouldn't take for 4 weeks before the test. Also have been told to fast for 6 hours and not even clean my teeth, drink any water food etc. Is this all correct and are then any adverse effects from this treatment?