Andrew Left Vs. Mallinckrodt CEO Debate Live On CNBC: What You Missed

Mallinckrodt PLC (NYSE: MNK) shares sold off 14 percent on Tuesday after Citron's Andrew Left compared the company -- again -- to Valeant Pharmaceuticals Intl Inc (NYSE: VRX). "Mkt. is starting to realize that $MNK equal risk to $VRX," Left tweeted around 2pm ET.

Valeant finished the day down 50 percent after poor earnings and guidance, along with the reiteration it's still under an SEC probe.

Earlier in the day, Left told TheStreet Real Money Mallinckrodt was the "poster child" for price hikes of pharmaceutical drugs. "Mallinckrodt is squeaking by without anyone talking about it. Mallinckrodt makes Valeant look like a bunch of choirboys,” Left added.

"At least Valeant can say, 'Hey, look at our products.' Mallinckrodt has one product that's never been tested," Left explained, in reference to core drug Acthar.

Mallinckrodt CEO Responds To Left Live On-Air

As Left told his thesis to CNBC on Tuesday evening, producers were surprised when Mallinckrodt CEO Mark Trudeau called in to debate the Citron head directly. Responding to the accusations its business model is similar to Valeant, Trudeau said the comparison didn't make sense, adding that the company is transparent operationally and financially.

Left, in response, said Valeant CEO Mike Pearson would say the same thing, telling Trudeau to properly test Acthar instead of calling into CNBC. Left also called Trudeau's defense "ludicrous," warning that he didn't explain to viewers how Mallinckrodt sells the drug.

Speaking directly to Left, Trudeau said comparisons of the company's debt levels and M&A activity to Valeant are "completely inaccurate," adding that it's "not close to what Valeant does."

Mallinckrodt shares were volatile but in the green after the head-to-head debate in Tuesday's after-hours session.