The word “pharmaceutical” is derived from ancient Greek “pharmekia”, which is a broad category which includes magic potions, poisons, medical drugs, and recreational drugs. (Of course, “magic potions” which actually worked were really one of the other three.) In that sense, it can mean “poison”, but it doesn’t always.
Though there’s another sense which medicines can also be poison: antibiotics, antivirals, antifungals, and antiparasitics. These are poisons which damage or kill an infecting agent, while doing minimal to no damage to their host.
And humans are remarkably resistant to a wide variety of poisons, so sometimes there’s enough of a benefit (or at least a perceived benefit, in the case of something like botox) to risk using something with a dangerous side effects.
using potent, venomous toxins and peptides from snakes, scorpions, spiders and cone snails
Occasionally, though in most cases once they’re proven to work they’re still produced artificially and not extracted from the animal in question. Also their chemical makeup is altered in some cases, to make it easier to produce, and when possible to maximize the beneficial effects while minimizing the negative ones. Also drugs come from everywhere, not just spooky 👻 monster 👹 bugs. 🦗 (I know, I know, snakes aren’t bugs…)
I don’t know where you went wrong, but I suspect it’s some form of “all vaguely connected things are identical”.