I have a ferret with CHF. He does well for the most part with oral furosemide. When he does have a breathing crises I have nitroglycerine cream that is put in his ear. It takes affect in about two minutes. I also need to keep him separated from his friends during treatment and for about 12 hours after the last dose. Directions are every 8 hours for two days. His ears get pretty gummy. This is my only experience with dransdermal meds. Ardith [Posted in FML issue 4723]