I've battled thrush with every baby. I can always tell I have it when baby's or my tongue is coated white, and when it gets bad my nipples get red and sore.
The first time we had it my MD gave us prescriptions. When I got home, I read about the drug and started crying--there was no way I was giving my baby that drug.
I found out that taking probiotics and placing some on baby's tongue too, helped. But to completely wipe it out, I made sure to wear my bras only once and use towels only once and to wash them in hot water. I also used white vinegar on my nipples after nursing.
It's not easy to get rid of, and I continued to take probiotics for months and months, but I felt much better using these methods than introducing such a harsh drug (or any drug) to baby.
I'm starting probiotics now for the birth of the next baby to hope to avoid thrush this time. As long as I end up with a homebirth like I want, I should be fine. But if I end up in the hospital again and they automatically give me antibiotics because my water breaks early or I run a temperature--then I know I better get ready for the thrush battle.