why do we still use methadone for opioid replacement therapy?? I can understand its past use, given its half-life. The only rationale I can see for using it compared to other modern long-acting opiates is that it supposedly blocks the euphoric effects of heroin. I haven't been able to find the mechanism of action for this in any of the articles I have looked at. Do other opiates (besides suboxone) do this??