|Be careful what the doctor perscribes you some times. I have been getting poison ivy since the day I could walk into some woods. I get so frequently and so bad, that I can just call it in. The bottle usually says for me... "Take 5 the first day, 4 the second day...and so on. Thankfully I didnt get it too serverly this time and i took 2, 2, 1 1/2, and then one today. If your taking 5 of these 20 mg tablets and 4 the next day and dont take your required dosage the next your body will have withdraws from the Rx. The withdraws from Prednisone are just like a normal sickness but, when you have poison ivy AND your sick, thats just the pits. Also, another thing that i heard that works when you know you have gotten into poison ivy (even if your not sure, better to be safe then sorry), Tecnu is about a 7 dollar squeeze bottle that you wash the area that you think has been in contact with the poison ivy. Hope my info helps out.
Also if you have severe poison ivy, wash your sheets on your bed as often as you can.