An antidote is a substance which directly counteracts the activity of a given poison.
Fantasy (and some Sci-fi) antidotes are usually universal (until the next splatbook introduces poisons that they specifically don't cure), frequently instant and often undo any damage done by the poison.
In the real world, they are often extremely specific, can be very toxic in their own right1, difficult to use, frequently slow acting and only serve to prevent further harm.
Antidotes divide roughly into the following (non-exhaustive) categories:
- Mechanical therapies: such as activated charcoal to adsorb swallowed poisons or EDTA chelation for heavy metal poisoning.
- Antivenins: complex, immunological preparations designed to counteract a specific venom.
- Supplemental doses: designed to react out or out compete a poison (such as calcium therapy for hydrogen fluoride poisoning or ethanol for methanol poisoning).
- Anti-drugs: interfere in the toxic action of the poison (examples include naloxone - used in opiate poisoning and N-acetylcystiene used to counteract paracetmol poisoning).
Another relevant (although honourary) addition to the list is adrenaline - this is given to counteract the effects of anaphylactic shock which, although an immune response and not toxic damage, can also result from some "poisonings", especially venoms.
It should, however, be noted that some poisons have no (known) antidote and that some of these are not 100% effective or reliable, particularly if the poison has had plenty of time to work on the patient. Most will need extensive supportive treatment to aid recovery and counteract their own negative effects and the majority will need to be administered by a skilled medical professional (or at least prepared very carefuly for amateur use).
Sci-fi or fantasy settings may also have nano-tech or magical cures which remove poison from the body - the universal antidote Mithridate (named after Mithridates, a king of Pontus with a morbid2 fear of being poisoned) appears quite a bit in classical and medieval legend. The panacea and the elixir vitae - two major goals of alchemy may also have had antidotal functions and of course there were always bezoars. Various other herbs and precious stones were said to be specifics against certain poisons and/or to draw venom from wounds and the horn of a unicorn was said to detoxify any poison.
Mithridatism - named after the same bloke as Mithridate.
Game and Story Use
- To amuse your players, try introducing specific antidotes for specific poisons - suddenly, instead of being something everyone carries a dose of (in fantasy games at least) it becomes a job for the healer to identify and prescribe the correct treatment from his (hopefully extensive) collection of remedies.
- You can still keep the magic, broad spectrum stuff, just jack the price up appropriately.
- PCs can be sent hunting toxic beasts for their venom by someone that wants to make antidotes - and looking for other rare herbs and minerals for the same purpose.
- Fake antidote may be a significant hazard for the tight fisted shopper (or one who has annoyed the local apocatheries).
- In a modern setting, toxicology is another useful skill for the team medic to pick up, allowing him to prescribe the correct treatments. Expect to carry several kinds of regionally appropriate anti-venom into the bush.