I believe the answer is that Leeches is the only appropriate card for removing poison counters from players, based on this question, but I'll ask anyway since I have observed this card posted elsewhere as an answer to poison counters.
Can cards which remove counters, such as Clockspinning, be used to remove poison counters or is Leeches the only appropriate response? What about the same question but targeting the -1/-1 counters on creatures?