- Select the poison you want in talents (i.e Paralytic Poison).
- When you have entered arena, remove this point and pick another point ("Prey on the weak" or "Dirty tricks").
It will keep this poison active for 1 hour, and the new talent point until the end of arena, so you have to do this each time you enter arena.
This works for both Paralytic and Leeching poisons
Maybe it can work the same way for another class.
Not a repost from another website, and haven't found something similar here