If Trump is killing off cocaine drug runners (in Venezuela boats) so there will be less

[AZJonnie]

19. Some might, but they are inherently very different drugs

Uppers vs Downers, essentially. And neither drug can be substituted to significantly mediate the effects of withdrawals from the other. There's not nearly the same direct line as the one that can be drawn between, say, the stricter enforcement of Rx laws over pharmaceutical opioids leading to more people taking (much more deadly) illicit fentanyl and heroin.

But sure, there would some who might switch to the opioids if cocaine were unavailable, with potentially deadly consequences. It's likely a lot more would turn to meth though, as it's much more similar to cocaine in effect.