I am sorry but I don't agree with this idea.
Why?
If you are meaning sterilisation for BOTH sexes in this case,then OK,but if it's for women only then no.
Drug addicts are often unable to function in the real world(due to their addiction),how are they to judge whether or not this is right for them?
This smacks too much of Hitlers ideas of Eugenics.That is manipulation of the population by genetics to weed out the disabled,the socially inferior(drug addicts) or any other part of the population that a government sees fit to erradicate.
Just WHO decides which and why the person to be sterilised is to be,I doubt that it will be doctors,rather civil servants will lay down the rules (laws?) and we all know how badly drawn up many such rules are.
This is another case of "shutting the stable door after the horse has gone".That is finding a (bad) possible cure for something that should have beed addressed before the addiction etc had got to that stage.
I suppose those in favour will(in their blind blinkered way) assume that sterilisation will be the cure all,it won't,it will just mean there will be lots of sterilised drug addicts about,but they will still BE drug addicts!
This is very bad logic.