What Causes Dizziness And Weakness While On A Butrans Skin Patch?

My doctor put me on a Butran s pain patch of 10mcg/hr and it was too strong because it started giving me violent headaches and sick at my stomach so I decided (stupid decision) to cut them in half and use them until I could get my doctor to change them. Then I finally remembered to call my doctor and told them and they told me that it was very dangerous to do that. I have been having terrible dizziness and weakness all day today and my blood pressure went from 100/68 to 145/95 and I have had heart flutters, extreme fatigue, and symptoms mentioned above. I took the patch off the day before yesterday and my blood pressure was a little low later that afternoon but I woke up with all these symptoms this morning and I am still having them. I m not sure if it s withdrawal or too much medicine from the patch I had on day before yesterday.