Taking nystatin does not work.having oral thrush and amalgam fillings don't mix. the candida/thrush will never go away, antibiotic resistant and sick.

Resistant Yeast: If you are on multiple antibiotics and have been taking common anti thrush medicine like Nystatin for some time, it is more than likely that the yeast has become resistant, for which your doctor needs to give you other anti fungal melds like Fluconazole or Amphitracin. Culturing the oral yeast with sensitivity will provide useful info on medicines which would work.