The Tánaiste was responding after he and the Sinn Fein deputy engaged in highly personal attacks on each other in the chamber last week.
Describing his stance as “self-defence”, Mr Vardakar admitted on Newstalk Breakfast that it "probably didn't" reflect well on politics”.
"I won't go through the detail of it, but in my mind it was very much self-defence,” he told the station.
"Sinn Féin - whether it's their supporters online, or their supporters on the streets, or their politicians in the Dáil - are constantly trying to attack us personally and bully us and do us down on the Government benches.
"Every now and then, I think you have to stand up to bullies.
"I think the way they try to demonise their political opponents - sort of make out that they care about people more than us.
"It started off, let's not forget, because Pearse Doherty alleged that my party was out of touch because I'd steak and chips with Jimmy Deenihan in the members restaurant the night before - no public money involved.
"Yet they can go on their exotic, fundraising trips around the world and drink champagne, and they're totally down with normal people.
"When you have to listen to that kind of stuff day-in, day-out - I think even for your own mental health, every now and then, you have to snap back.”
Mr Doherty had criticised the Tánaiste following a response to a question over a dinner Fine Gael held last Wednesday, saying that he "really thought somebody who, in which the DPP is currently assessing whether they'll prosecute you under the Corruption Act, maybe you would be a bit more humble in relation to your response".
Varadkar replied by bringing up a previous prosecution Doherty had received when he was younger.
"Deputy, I think that was another cheap shot and a very personal shot," Varadkar began. "And it says a lot about you and the nature and the character and kind of person you are, and it's particularly strange coming from you because you were prosecuted.
"You abused, mistreated, a Garda Síochána. For that, you were prosecuted. You were found guilty. Yes, you got away without a conviction because of your age at the time but you were actually prosecuted, you were arrested – that's what happened to you.
"And in your party, there are a huge number of convicted criminals in your party and in your wider Republican family," the Tánaiste continued. "Whether that is tax dodgers like Slab Murphy, a 'good Republican' according to Mary Lou McDonald, a good Republican, a tax dodger, people who are convicted for murder. We know what your party's attitude is to rape and paedophiles and what you've done in relation to that.
"So your cheap shots, your cheap shots say a lot more about you than they do about me."