Anna Nicole Smith walks into the Ronald Reagan Federal Courthouse in Santa Ana, Calif., in this 2001 file photo for a hearing involving her fight with her stepson over the millions left by her late husband, Texas oil tycoon J. Howard Marshall II. Smith, who died Feb. 8, was found to have received prescription drugs under an alias.

Los Angeles ? If a prescription needs to be filled in Hollywood, chances are celebrities can find a doctor to do it.

Doctors have a long history of feeding the drug demands of the entertainment industry from Marilyn Monroe to Winona Ryder, Elvis Presley to Courtney Love.

Now, California authorities are looking at a physician who reportedly prescribed methadone to Anna Nicole Smith under a fake name. The former Playboy Playmate died Feb. 8 after collapsing at a Florida hotel. The cause is under investigation.

The allure of having a star as a patient can sometimes influence whether doctors follow the rules or break the law, one veteran Hollywood publicist says.

“It’s not easy to say no to a celebrity,” Michael Levine said. “History has taught us whether it’s Anna Nicole, Elvis or John Belushi, they can get what they want. It’s like water.”

Monroe died at 36 from an overdose of sleeping pills in August 1962. She had been under a doctor’s care at the time, police said.

Presley, who died in 1977 at 42, was known to travel with George Nichopoulos, a former physician who overprescribed drugs to clients, who also included rockabilly singer Jerry Lee Lewis.

Members of the medical team who performed Presley’s autopsy acknowledged in 1990 that the singer was addicted to prescription medications and his death may have been hastened by “polypharmacy,” a reaction to mixing many drugs. Nichopoulos lost his medical license but was acquitted of related criminal charges.

“Top Gun” producer Don Simpson was found dead of a drug overdose at his Bel-Air estate in January 1996. Traces of 21 drugs were found in his blood, and at least two doctors were investigated for overprescribing medications for Simpson.

More recently, celebrities have used fake names to get their vials filled. A 2002 probation report stemming from the shoplifting arrest of actress Winona Ryder showed that she used a half-dozen aliases when she sought prescription drugs. The report said Ryder went “doctor shopping” and had 37 prescriptions filled by 20 doctors over a three-year span.

“It’s not uncommon for a high-profile person to get a prescription filled under an alias,” said Ryder’s attorney, Mark Geragos, citing a celebrity’s need for privacy. “It happens with great frequency.”

The California Health and Safety Code includes several sections stating that no person who prescribes or dispenses a controlled substance may give a phony name or address or make any false statements on the prescription form. Geragos said the onus is on the doctor.

In Ryder’s case, Jules Lusman pleaded no contest to practicing medicine without a license and grand theft, and was sentenced to five years probation.

This past week, California’s medical board opened an inquiry as investigators tried to determine if there was any misconduct by Dr. Sandeep Kapoor, who reportedly prescribed methadone to Smith. The celebrity news Web site TMZ.com said “Michelle Chase” was an alias used by Smith in a pharmacy receipt for a methadone prescription.

Methadone is a popular narcotic painkiller that is used as part of drug addiction detoxification and maintenance programs. Methadone overdoses can cause shallow breathing and dangerous changes in heart beat.

An attorney for Kapoor, a 1996 graduate of Boston University School of Medicine, said in a statement Friday that his treatment of Smith was “sound and appropriate” and he will cooperate with the state’s medical board.