Nystatin powder

How/where can you get nystatin powder? I went through three doctors/NP before one said that they would prescribe it if I could find it and find out the right dosage. The pharmacists that I have asked look at me like I'm crazy. Even the compounding pharmacy said that they don't dispense the powder, only a capsule. Is it really necessary to have the powder? I have had four two-week rounds of Diflucan over the last five months. The last doctor I saw (one week ago) prescribed more Diflucan and advised me to start the candida diet (which I have). I am concerned about the Diflucan's effect on the liver and would really like to try the nystatin. Why can't I get it?