Mexican cartels have insured that super pure meth and heroin are flooding our streets in huge supply, and at low cost to the users. Every time I hear a Mexican President complain about a wall being built at our border (which might help bust some of the mules) I feel like wringing his neck and shoving his face into a mountain of this poison. This is the primary source of the problem IMHO.
Put the big dealers, particularly the "importers", out of business with extreme prejudice.
Punish the foreign governments who are either actively involved or looking the other way. Help them to get their minds right.
Offer the users, the addicts, an opportunity to get rehabbed and back to work, or maybe to work for the first time, once.
If that fails, or if they relapse, they get sterilized and then get to go live in a special resort for the rest of their lives, with three meals a day, and plenty of productive, physically vigorous activities to keep them busy and their minds on things other than dope. They might even enjoy certain aspects of it, who cares, but... no more life amongst the living and no more influencing the yutes.