Hmm. Maybe you were thinking about elemental mercury vs methyl mercury? That’s a case where the danger (at least through ingestion) depends greatly on the format.

This is probably the worst example to choose, because in the US the generic name is acetaminophen. This is a case where the brand name actually unites understanding of a drug whose chemical name differs by location.

That being said, I still agree with the spirit, let’s stick to referring to the drug and not the brand.