If you are referring to opiate addicts, the have access to methadone and seboxone programs. Both clean, both minimize withdrawal symptoms. Both are monitored.
The problem with drug addiction (especially the opiates) is not the addiction to the drug itself, but the multitude of other health problems and social consequences that are connected to the addiction. Since the vast majority of opiate addicts are indigent, we as a society end up paying the cost of these consequences. We need to use a harm reduction model in dealing with this problem. But just mention a clean needle program, which has been shown to drastically reduce the negative consequences to both the addict and to society, and watch the conservatives turn blue.