How do you successfully deal with Ki'Kathal as melee?

Playing ENH and as soon as there are more melee river me and tank, we got problems when poison debuff goes out.

I am trying to alligk myself so I don't damage others with the poison. I can also poison cleanse the first and next round of debuffs.

But I find poison debuff along with webs and black hole spell doesn't give me much dpanuptime on boss and I want too better myself.