For proof of how one outstanding performance can give elevate a middling movie, look no further than director Edward Zwick's "Love and Other Drugs." Based on Jamie Reidy's "Hard Sell: The Evolution of a Viagra Salesman," the film starts off as a reasonably raucous and raunchy comedy revolving around fast-talking Pfizer pharmaceutical peddler Jamie Randall (a vibrant, funny Jake Gyllenhaal), who isn't thrilled to be pushing Xanax in the Ohio River Valley in the late 1990s, until he meets bohemian artist Maggie Murdock (Anne Hathaway).
In what begins to seem like a rewrite of the Robert Downey Jr./Molly Ringwald comedy "The Pick-Up Artist," Maggie proves to be every bit as smart, sassy and sexually adventurous as Jamie — perhaps even more so. Although former "Brokeback Mountain" co-stars Hathaway and Gyllenhaal generate plenty of steam (and "Drugs" goes much further than most mainstream movies in terms of the frankness of its love scenes), the real fire in the film comes when Hathaway begins to strip Maggie down to her emotional center, to tear away the various attitudes and evasion tactics this feisty young woman uses to protect what must be an often wounded heart. As her comfort zone disintegrates all around her, Maggie furiously fights to hold onto her dignity and her self-esteem; Hathaway makes the struggle completely engaging and, at times, even heartbreaking.
The unvarnished honesty in her acting, however, is at odds with much of the rest of "Drugs," which tries to balance Maggie's crisis with goofy shenanigans that Zwick doesn't always know how to pull off. Jamie becomes one of the first salesmen to offer Viagra (introduced in the movie to the strains of Belinda Carlisle's "Heaven is a Place on Earth"), which leads to many increasingly strained double-entendres. Josh Gad, as Jamie's obnoxious younger brother, might as well have walked in from an "American Pie" sequel, while Oliver Platt, playing Jamie's troubled mentor, doesn't get enough screen time to establish his potentially fascinating character, a veteran salesman who works to support a family he never has time to see.
By the 90-minute mark, "Drugs" has changed styles and tones so frequently you might wonder if you're not watching a compilation of scenes culled from three or four different films, all featuring the same cast. Even when the movie threatens to become as unwieldy as one of those laundry lists of "possible side effects" at the end of every pill commercial, it's worth putting up with the many mood swings simply to savor the rich rapport between Gyllenhaal and Hathaway, and to be enthralled by Hathaway's powerhouse solo scenes.