per deadspin.com:
Woods told officers that he was taking four medications, listed here as “soloxex,” “vicodin,” “torix” and “viox,” but noted that he hadn’t taken the last this year. (Vicodin is a painkiller; Torix and Vioxx are anti-inflammatories, though Vioxx was withdrawn from the market in 2004.)
i'm pretty sure the warning on the vicodin bottle says something along the lines of: may impair the mental and physical abilities needed to perform potentially hazardous activities such as driving a car or operating machinery.