Two friends and a few reviewers and a radio host with vertigo said they fought nausea a whole lot of time, and one ended up leaving after a while as he was about to be sick.
Another friend with an acute case of vertigo didn't even think of nausea.
That's a poor sample to work from, but I suspect it depends on what type of vertigo you have. As ironclad said, if it's the type where you don't feel bad looking out of windows or in planes and only open heights makes you dizzy, it seems OK. OTOH, if it's the type where you get dizzy even when people are falling or standing too close to the edge of a skyscraper in movies, Gravity seems pretty likely to be too much for your stomach/inner ear.
Personally the great dive in the opening scene of Revenge of the Sith made my stomach lurch when I watched it on the big screen, so much as I would have loved to see this one on IMAX 3D and was planning to, I'm gonna wait the Blue Ray for Gravity.
