(CNN) -- Even Denzel Washington's considerable magnetism can't rise above the shenanigans found in "John Q.," a mating of "ER" and "Dog Day Afternoon" that goes completely nuts after establishing its basic premise.

Director Nick Cassavetes and screenwriter James Kearns make Washington look silly for the first time in his career. That's bad enough, but you know a movie is in big trouble if you get giggly while a dying child lies in the hospital waiting for a new heart.

Washington plays John Quincy Archibald, a down-to-earth factory worker who's having trouble paying his bills. Right away, Cassavetes' thudding lack of subtlety is established: Early in the movie, at the exact moment that John and his wife, Denise (Kimberly Elise), are watching President Bush discuss the failing economy on TV, a repo man tows their car away. The couple is afraid they might even lose their home, but at least they have their cute young son, Michael (Daniel E. Smith), to distract them.

Their bad luck continues, however, when Michael collapses on a Little League field and it's determined he'll need a heart transplant or face certain death. This is semi-explained to the Archibalds by Dr. Turner (James Woods), a smarmy surgeon, and Rebecca Payne (Anne Heche), a cold hospital administrator.

Turner employs such esoteric medical jargon when he talks, you'd think he's never spoken to a non-physician before. But Ms. Payne (note the "clever" name) makes one thing perfectly clear: John's HMO doesn't pay for transplants, so he and his wife will have to raise $250,000 to cover the cost of surgery.

Outright foolishness

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At this point, "John Q." is nothing more than an expensive disease-of-the-week movie, but at least it's believable. Such situations do occur.

Unfortunately, outright foolishness takes over when John can't raise the cash. In desperation, he grabs a handgun, drags Dr. Turner into the hospital's emergency room, and demands that Michael receive a transplant. He chains up what appears to be the sole door leading to the room, and tells everyone else, including staff members and a handful of patients, to sit tight while he waits for the cops to fork over a healthy heart.

Cue Robert Duvall, as Grimes, the gruff hostage negotiator who will slowly come to respect John's reckless gumption.

Grimes, of course, is required to have a less-experienced superior who prefers SWAT teams over negotiating. So here comes Ray Liotta, as Monroe, a media-savvy golden boy who shows up wearing a dress uniform covered in shiny stars and medals. Monroe casually poses for photographers before deciding it would be best to try to shoot John. Feel free to boo.

Wall-to-wall cliches

The hostages, for their part, are a grossly caricatured bunch who seem altogether disconnected from the man who's waving a gun in their faces.

They fit every idiotic Hollywood stereotype, ethnic and otherwise. There's Lester (Eddie Griffin), a cackling, jive-talking African-American, and Mitch (Shawn Hatosy), a mean-spirited loudmouth with a busty girlfriend who we immediately realize he's been beating -- not that it stops Cassavetes from treating the information as a huge surprise later in the movie. There's also a slovenly 300-pound security guard and a very pregnant Hispanic woman to keep the cliches percolating non-stop.

Initially, John seems to mean business with that gun. He just about has to, if you want any tension in the emergency room. But he soon forces Dr. Turner to take care of the waiting patients, and even makes him perform emergency surgery on one guy.

This do-gooder reversal is par for the course. All the character motivations are flimsy at best, with several about-faces coming in a third act that's so ridiculous, it's the funniest thing to hit our screens this year.

Washington should leave this one off his resume and get on with his otherwise illustrious career. Cassavetes and Kearns, on the other hand, might want to plead insanity.

"John Q." contains profanity, violence, and a clear view of icky heart surgery. Look for the rich guy who gets wheeled out of the hospital while wearing an ascot, a move that would make Thurston Howell III proud.