LOS ANGELES — Rob Reiner’s junkie son Nick failed to appear in LA court Tuesday to face charges that he slit the throats of his famed director dad and mom — with his high-profile lawyer saying he has yet to be “medically cleared.’’

Celebrity lawyer Alan Jackson told reporters outside the courthouse that his client’s first appearance in court could be as early as Wednesday, although that will be decided on a “day-to-day” basis.

“Every inmate has to be medically cleared before they can be transported to court,” said Jackson — who has previously represented fallen Tinseltown powerhouses Harvey Weinstein and Kevin Spacey. “He has not been medically cleared, it’s just a procedural issue.”

The lawyer refused to say who is paying Nick’s legal fees, including whether the Reiner family is involved.

Ne’er-do-well nepo baby Nick is accused of killing his dad Rob, 78, and 70-year-old mom Michele inside their Brentwood home sometime between Saturday night and Sunday afternoon.

Nick, 32, checked into the Pierside Santa Monica hotel around 4 a.m. Sunday, and hotel staff later found the room soaked in blood, according to TMZ. Nick did not have blood on his clothes at check-in, the outlet said.

He was taken into custody Sunday evening about 15 miles from where his parents were discovered dead by their daughter, Romy, in the upscale Los Angeles neighborhood.

He has since been held in custody leading up to Tuesday’s canceled court appearance.

It’s unclear what medical issue specifically kept him from court, but the middle child has battled drug addiction for years and was placed on suicide watch after he was detained, law-enforcement sources have told TMZ.

Jackson said prosecutors have not officially filed any charges, but former federal prosecutor Alyse Adamson told CNN the Los Angeles District Attorney’s Office is likely trying to sort out whether he should face first-degree or second-degree murder charges.

“First-degree murder, of course, suggesting that this was planned and premeditated, second-degree murder being more spontaneous,” she said.

Jackson is known for repping an assortment of high-profile clients.

He recently represented Karen Read, the Massachusetts woman who was found not guilty earlier this year of running over and killing her boyfriend, Boston cop John O’Keefe.

Jackson has also represented rapist producer Weinstein and accused sex-assaulter star Kevin Spacey.

Nick had an explosive public argument with his parents at Conan O’Brien’s Christmas party Saturday night, according to sources.

Rob, who was born in The Bronx and grew up in New Rochelle in Westchester County, is known for directing a series of acclaimed movies, including “This Is Spinal Tap,” “A Few Good Men,” When Harry Met Sally” and “The Princess Bride.”

He shot to prominence for his role as Michael “Meathead” Stivic the 1970s TV classic “All in the Family.”