The cast and crew have tried hard, but they haven’t been able to crack the nut that novelist Chuck Palahniuk fashioned in “Choke.” The incendiary material, edgy humor and radical shifts in tone in which the book reveled are simply beyond the adaptive skills of the filmmakers; their movie strains to be wickedly funny and provocative, but comes across feeling curiously pedestrian and tepid.

The central figure in the madcap plot is low-life Victor Mancini (Sam Rockwell), a medical school dropout who’s taken a dead-end job playing an indentured servant at a cheesy colonial-village recreation park where everybody slinks around desultorily except for the gung-ho fellow who’s the town chief, Lord High Charlie (writer-director Clark Gregg). Vince supplements his meager income—per the title—by pretending to choke in restaurants and accepting gifts from the people who, after “saving” him with the Heimlich maneuver, feel responsible for his future wellbeing. Victor, along with his best buddy and co-worker, a big lug named Denny (Brian William Henke), is also a sex addict who’s joined a therapy group (led in a cameo by Joel Grey). But all he actually does during the sessions is make out with the female participants.

Mancini isn’t a complete scumbag, though. His entire income goes to paying the cost of maintaining his increasingly addled mother Ida (Anjelica Huston) in a nursing home, even though—as we see in flashbacks—she was hardly a prize parent, often dumping him with foster families until she felt like stealing him back again. Ida’s getting so far gone that she can’t even recognize her son anymore, but her new doctor Paige Marshall (Kelly Macdonald) has some strange ideas about how she might be helped, including she and Victor having intercourse in the hospital chapel. She also claims to find a great secret in Ida’s Italian diary involving Victor’s paternity. Let’s just say that Dan Brown has nothing on old Ida’s alleged recollections.

A farrago of raunchiness, religious satire, slacker goofiness and con-man farce like this would require an especially nimble touch to avoid coming across as a mess, and Gregg—though he’s actually quite funny as the pompous but emotional Charlie—doesn’t have it. Rockwell certainly goes for broke as Victor, in every sense, and he’s matched by the likable Henke (who makes the hulking fellow’s romance with an airhead pole dancer who introduces herself as Cherry Daquiri and adds gravely, “It’s not my real name,” one of the warmest aspects of the movie). But their efforts aren’t matched by the rest of the cast—including Huston, who does nothing special as Ida, and Macdonald, a blank Paige)—but it’s Gregg’s inability to invest the piece with any particular style or mood that leaves the picture feeling far too bland and shambling for its own good. The deficiency is accentuated by a production that’s frankly mediocre; presumably Tim Orr’s drab, gritty cinematography and Roshelle Berliner’s equally grim production design are meant to mirror the shabbiness of Victor’s existence, but without the compensation of a truly imaginative approach to the material they just seem the unfortunate result of budgetary constraints.

Even if you appreciate Palahniuk’s book—and he’s an acquired taste, anyway—it’s unlikely that you’ll find this adaptation a worthy reflection of its peculiarly ribald, anarchic spirit. In its screen form, “Choke” may aim to be outrageous, but despite the wildness of its narrative, it’s just a perfectly ordinary failure.