Yes those are all completely different drugs lol I don ' t understand how you can even argue they are not . The presence of different chemistries inheritely makes them different drugs . Adding a functional group changes mass , density , pharmacology , metabolism , nearly literally everything about the drug . Diacetylmorphine technically is inactive , it is known as a prodrug . Meaning metabolism must occur within the body to change the structure to the active drug 6 monoacetylmorphine . Which can further be metabolized to the completely different drug , morphine . If you take morphine by itself , no metabolism is involved , no need for enzymes to make the drug work . <| sep |> I ' ve had something like this recently . Think it ' s something to do with WhatsApp .