I'll raise you one better. Cannabis is Schedule I, that means per the DEA there are no known safe medical uses for the drug. But if you synthesize out the primary active ingredient and bundle it in capsule, the DEA happily recognizes that as a mere Schedule III drug, and you get get a prescription for it even in states where cannabis remains illegal at the state level. It goes by the brand name Marinol.

> and also completely legal to buy in certain locales

I'm not trying to be pedantic, but it's important to understand that according to federal law it's not actual legal to possess them regardless of which state you're in.

They're still illegal under federal law. A person could technically be prosecuted at the federal level even in a state that doesn't have state-level laws against it, though that's unlikely in practice.

while at the same time, Fentanyl is a schedule II drug.