Not only do i have experience with it, i have SUCCESS with it...
And sentience, no offense but medically, other than your pet hate methadone

(jk) (since i know you will argue that it is) opiates aint toxic. the long term health effects are from users neglecting their health, not using clean sets, cuts in the drugs, etc. Using a bag of dope or a oxy aint no more damaging to your body than takin some acid or smokin some bud.
Anyways....i aint got time to answer this question now but I will tell you that I been usin opiates since I was 14 yrs old and Im almost 24 now. I first tried dope when i was 16 and ended up shootin dope for years. It aint about dicksizin like "my habit was THIS big and THIS bad" but just so u understand that it was HARD to break becuz i had been doin that shit for most of my teenage and adult life and spent more of my time as an "adult" shooting dope than ever sober.
i say that shit cuz IMO, when somebody has a 6 month long affair with sniffin a few bags of dope a day then they get clean and then they say oh, i can use again without a problem occasionally, people be like "yea, well you never had a "real" addiction to begin with, a 'hardcore junkie' wouldnt be able to do that", etc. So im just sayin, by all definitions i was "a hardcore junkie" as stupid as it sounds to use that description. But i did get that shit over with and had no problem usin successfully, occasionally like once every few months....Ill expain more later tho, i gotta get my ass to the dr now.

just wanted to cast one more vote for 'yes'