I've seen many people abusing this card, and there's nothing you can do to counter it. It's especially bad when someone is using a gun that sprays. I think it should have a time limit (just like with the piercing bullets) or at least decreasing the damage massively.
#Poison bullets needs changes
low trellis
vapid copper
Maybe it only lasts for a couple mags?
viscid oasis
or just have a hardcap of like 7 max dmg at any given time
austere quiver
Make poison bullets & vamp bullets be Mag based so that they need card sinergy / empty mag counters it :D
They're pretty much 1 card army if used right
viscid oasis
i think making them time based would go better than mag based imho
austere quiver
Time is a comodity in this game, few cards can give you a breather unless you're running away the whole time (which is sad and lame). If the way to nerf everything would be to make it temporary, that just push matches to go face to face asap, removing the beauty and the creativity of using different cards setups
viscid oasis
then make it like 2/3 mags instead of only 1 at least for the pistol/laika