I think it's a derivative of opium so there's obviously addiction to contend with, you'll probably become tolerant to it and I think it might make you itch. Might also affect your sleep if you become a long term user. My Granny has been taking a consortium of different opiate derivatives since the 60's and she has terrible bother sleeping nowadays, gets up and does her house work in the middle of the night and stuff. That said, she's fit as a fiddle but for a new hip, being hard of hearing, and having what we presume to be mild parkinsons which hasn't seemed to get any worse in the 20 years I've known her. She is the same age as the queen and had smoked like a chimney for over 50 years before giving up recently so it can't be that bad. I think thrush, ulcers and kidney problems might also be caused by it but I'm no doctor. Kidney problems and ulcers I would suggest becuase if its anything like heroin it will dry you out a bit, which is also why it causes the constipation.