I suspect this comparison is made in jest.
There is no comparison between heroin & Tylenol. Heroin is far more dangerous, because heroin leads it's user to loose all of his human traits, & take on the characteristics of a monster. It blots away the consciousness & petrifies the soul. Tylenol may be toxic, but I just do not see it as having the same effect on a person's higher life, which ultimately trickles down to his physical life, as that cursed substance.