I have studied alot about Nystatin and I believe that it is harmless. It passes through the gut and is not absorbed into the bloodstream. Doctors had 4 of my kids practically from birth on Nystatin for a year, and they never had any side effects. It is precisely because it is not absorbed systemically that they won't prescribe it for vaginal yeast infections. Also I had one experience where I went on ketoconazole for 30 days straight, combined with a strict diet of vegetables and meat. For the first few days, the vaginal itching seemed to get better, but by the end of the course it was much worse. The doctor diagnosed me with bacterial vaginosis (overgrowth of bacteria in the vagina.) If you can't seem to get the itching under control, and the antifungals don't seem to be working it makes sense to have them look at it. Vaginal infections usually have a possibility of 3 different diagnosis: trichomoniasis (a protozoan I believe), yeast, and bacterial vaginosis. They are treated differently. If you have a good gynecologist, they should do a vaginal smear, and have it examined by a lab. Not just do a physical exam and say "I think it's yeast".