I had a Dr. one night write H2S04 dressing change bid. I couldn't figure this one out. I faxed it to pharm. and they said there is no such thing. Had several nurses that deal with this Dr. a lot come and look at it and they couldn't make sense of it either. I finally had to call him. He told me I just wrote for a Silvadine dressing change. I told him no you wrote H2S04. Wow did I? I took me 2 hrs of invesigation. Arrrghhhhh.