methylene blue toxic to plants? (use of Furan 2 in planted tanks)

Hi,

I've looked for this info everywhere, and I'm getting mixed messages.
I'm hoping someone has experience with it to tell me the real effects..

I have a fish suspected of saddleback disease (columnaris). I am in
the process of removing the affected fish (2 gouramis) to the
quarantine tank, but I am afraid I may have to do some prophylaxis
medication of the main tank as if it really is columnaris, it's very
contageous.

I've been looking at Furan 2 made by Aquarium Pharmaceuticals. It
contains nitrofurazone and methylene blue in crystal form. I will be
medicating the two obviously sick fish in the quarantine tank, and
since that tank is bare, I have no issue using it in the quarantine
tank. however, the main tank is heavily planted... so I am more
cautious.

I have anubias, amazon sword and java fern in my main tank. will the
methylene blue in Furan-2 kill my plants?

linda