Patrick Dempsey may have re-established his heartthrob status as Doctor McDreamy on NBC’s “Grey’s Anatomy,” but his sex appeal still isn’t getting him quality film roles. That fact is made painfully evident by the disappointing premise of his new film “Made of Honor,” to say nothing of the film itself, which boasts all the charm of a tampon commercial.

Mr. Dempsey plays Tom, a misogynist gad-about-town who made a fortune creating “coffee collars” — cardboard coffee sleeves that provide the perfect display for Starbucks product placements in the film. Tom balances evenings of one-night stands with platonic escapades with his college friend, Hannah (Michelle Monaghan), who must have been a super-genius to have been in college at the same time as her middle-age paramour. But when Tom finally realizes that he wants something more from Hannah, it’s too late. She returns from a trip to Scotland with a fiancé (Kevin McKidd), and gives Tom the unenviable role of maid of honor.

On top of stealing the plot from “My Best Friend’s Wedding,” “Made of Honor” pays only minimal attention to anyone besides its star. Those who come to gawk at their favorite TV doctor will be sated. As Tom, Mr. Dempsey is sweetly scruffy, adorably caddish, and lit to perfection, while Ms. Monaghan is left in the shadows with ill-fitting dresses and bad hair — a discrepancy that becomes unforgivable when the filmmakers send the charming actress down the aisle with Fabergé egg hair for the sake of a weak joke.

Once “Made of Honor” finally loses any sense of restraint, it sacrifices its star’s masculinity to try to breathe some life into its dwindling story line; the indignities of Mr. Dempsey in a mini-kilt and the resulting up-skirt shot prove most egregious. Mr. Dempsey handles these indignities serviceably, a trick gleaned as a teenager, when he played eye-candy roles in such films as “Loverboy” and “Can’t Buy Me Love.” But that sort of gawky humor isn’t as becoming on a grown-up.