I love the mechanics of this card, and it's very well balanced. Otyughs could eat poisonous creatures with this? Also interesting that unupped is a spell, but upped is a permanent. I guess SoG is like that, but unupped shard does nothing.
The name of the upped version doesn't seem to fit though. Antibiotics kill biotic things, such as bacteria. Poison isn't caused by bacteria, but by toxic chemicals. It's different from disease. But I guess viruses aren't affected by antibiotics, nor are they poisonous, yet they still cause poison. So it's not a big deal.
My brother said the same thing, actually. I named the upped version of the card "Antibiotic" because antibiotics are generally mass-produced, fitting the re-usable effect of the card. Antidotes, as far as I'm concerned, aren't.
I also have some issues with the naming, maybe it could be changed to Antivenom | Antidote.
Antidotes are pretty simple compounds, so those are in fact generally mass-produced. Some (for example EDTA) even in much larger quantities than antibiotics. Keeping your original, well thought, reasoning in mind, name Antivenom would make sense. Antivenom is a biological product (antibody to be exact), that can be used to treat envenomation. Those antivenom molecules (as all antibodies) are much harder to produce than most other medicines.