Sales of the pain reliever Vivomo soared 90 percent in 2012, meaning a 70 percent increase in royalties for Pozen (Nasdaq: POZN), the Chapel Hill-based pharmaceutical firm reported Wednesday before the markets opened.

Vivomo is marketed and sold by AstraSeneca, Pozen’s partner.

The big jump in sales to $64.3 million meant $4.8 million in royalties, Pozen reported.

However, the company still reported a net loss of $25.3 million, or 84 cents a share.

Pozen reported net income of $42.3 million in 2011, largely due to a deal centered around a $71.9 million deal for its revenue stream from the pain reliever Treximet.