There’s a legal standard they would have to follow to avoid commerce clause problems called “undue interference.” IANAL so cannot define it directly for you, but it’d be hard to argue outright banning isn’t undue interference. Whereas regulations may be permissable in some cases like you mentioned with opiates. But you won’t see a state that has a law outright banning sale of an opiate that’s approved for use by the fda for this reason.