All modern vampire tales are variations on an “addiction” allegory. The “victim” needs her or his “fix.” Even in the “Twilight” movies, that was what played out — Kristen Stewart was addicted to Robert Pattinson’s pale (literal) sparkle.

“Painkillers” is novel in that it removes the subtlety of that allegory. A victim, not bitten (but infected, via transfusions or something) craves blood. He gets the hollow-eyed shakes without the taste of it.

And damnit, Jim, he’s a DOCTOR! He should be able to figure this out.

“Painkillers” is an indie production that bills Mischa Barton as a “star,” when really, she only had to show up for the opening scene. She plays the nameless victim of a vampiric slasher attack outside of a club.

“See Mischa Barton getting her wrists cut and sucked!” That’s that for Mischa.

Cut to a suburban surgeon dad (Adam Huss, making the most of his first starring role in film), playing with his son (Tate Birchmore), doting on the lad, and then playing the stupidest version of the “Wanna see something scary?” game ever. He turn the headlights off ass they drive home — in the dark.

Stupider still, that isn’t the exact reason they crash. Silly screenplay.

Dr. John Clarke wakes up in a coma and lurches into spasms of grief upon hearing the news that his boy died. He tumbles into the delirium tremens — uncontrollable shaking, alarming.

His Head of Medicine (Debra Wilson) is stumped. “Nothing is physically wrong with you.”

His wife (Madeline Zima), already heartbroken, is gutted that they cannot talk about this and that he is unable to return to work or function in any normal way.

But this Morris fellow (Grant Bowler) sidles up to him at his kid’s funeral and assures him, “I can help.”

And after John cuts his hand and discovers the restorative/curative powers of sucking a little blood, he looks this Morris fellow up.

“You drank your own blood, and the pain went away,” he’s told. “That particular cure works only once.”

How convenient. For the movie, I mean. Morris reassures John that he’s not a “vampire.”

“You’re NOT going to live forever. You can go out and enjoy the sun. Enjoy garlic on your steak and your good looks in the mirror.”

No. He’s just another junkie. He’s hooked. But to get his fix, he’s going to need to “adjust your notions of good and evil.” Besides, not everything’s black and white simple. He’ll be living in a “grey” area from now on.

As the stark string duo score (by Dustin Morgan) shrieks its approval, John dodges Morris’s offer to “help” and being a doctor, avails himself of easy access to blood for “my condition.”

Fans of splatter films and bloody vampire pics won’t be bowled-over by these scenes of John collecting surgical leftovers and draining blood bank bags. They’re pretty damned gross, though. Getting a little nauseus here, remembering it to write about it.

But shortcuts like donated blood won’t cut it. No, Morris has an answer. It won’t be “wrong” so long as the people you hunt and drain kind of, you know, DESERVE it.

“What are we doing?”

“Justice!”

The “vigilante vampire” hook for this tale is like Ms. Barton’s brief appearance in it — terribly under-developed.

But what isn’t is Huss’s value-added performance in the lead role. A supporting actor best known for support work in TV’s “Power,” he gives us wrenching grief that bends into withdrawal symptoms. The shakes and twitches, uncontrollable bobbing up and down have you fearing for the character and buying into the notion that the man needs restaints.

No fooling. If Huss ever wants a job playing any other kind of addict, this is the highlight reel he should show the casting director.

“Painkillers” may not be much, and I’d have gladly accepted a longer running time (more vigilante scenes) than the 83 minutes delivered here if it meant the story had more moral dilemma meat on its bones.

Bowler has an understated villainy about his performance, Zima gives wife Chloe a gutted-by-grief cast and Wilson does OK at creating empathy for her character in just a couple of scenes.

But Huss holds center stage with a body-contorting commitment like few actors we’ve seen outside of an A-picture about addiction. It’s great work in a middling movie.

MPAA Rating: unrated, bloody violence

Cast:  Adam Huss, Madeline Zima, Debra Wilson, Grant Bowler, Tate Birchmore, Mischa Barton.

Credits: Directed by Roxy Shih, script by Giles Daoust. A Vision Films release.

Running time: 1:23