|Went to the doctor to get steroid shot to get rid of the rash from poison sumac. The doctor told me to buy Tagamet. An over the counter medication that used to be prescribed for stomach ulcers, when they thought it was caused by histamine. Tagamet is a histamine blocker and 50 times stronger than benadry and it doesn't make you sleepy. If you take it at the first signs of the rash, it'll shut it down quick, and you can even take it ahead of time if you plan to be in the woods or doing yard work that may expose you it. I'm sharing this info with everyone I know.