A Los Angeles-area doctor convicted of second-degree murder for prescribing pain killers that killed three patients was sentenced Friday to 30 years to life in prison in a landmark case that many in the medical community believe will create a chilling effect among physicians across the country.

Dr. Hsiu-Ying "Lisa" Tseng received the lengthy sentence after she apologized to the families of her dead patients and others who became addicted to prescription drugs under her care.

"I suffer every day from the impact and I will do everything I can to take responsibility," she said. "I have learned a very hard lesson on this that will stay with me forever."

That did little to sway Los Angeles County Superior Court Judge George Lomeli, who said Tseng wrote reckless prescriptions even after learning her patients were dying.

"(She's) a person who seemingly did not care about the lives of her patients in this case but rather appeared more concerned about distributing dangerous controlled substances in an assembly line fashion so as to collect payments which amounted to her amassing several million dollars," Lomeli said.

The mother of two children, 8 and 11, will be over 70 before she has a chance at release. She had asked Lomeli for a 15-year prison term.

Prescription drug abuse has skyrocketed in recent years.

Opioids — primarily prescription painkillers and heroin — were factors in more than 28,000 deaths across the U.S. in 2014, and opioid overdoses have more than quadrupled since 2000, according to the U.S. Centers for Disease Control and Prevention.

Tseng's murder conviction has sent a message to doctors across the U.S., said Dr. Bill McCarberg, president of the Chicago-based American Academy of Pain Medicine.

"Prescribers see that and they say to themselves and I say to myself, 'What did she do wrong and could that happen to me?'" McCarberg said.

The reaction will leave some people in legitimate pain unable to get painkillers, a problem that already has emerged amid a crackdown on improper prescriptions, McCarberg said.

"Providers are very hesitant to give any medication for pain, so they'll give a Motrin or an Advil," he said.

But more hesitation among doctors may not be such a bad thing, said Larry Driver, a pain medicine and clinical ethics professor at the University of Texas M.D. Anderson Cancer Center in Houston and president of the Texas Pain Society

"It may be an opportunity to pause and reflect for a moment and think rationally about appropriate care for a patient," Driver said.

He and McCarberg said they'd like to see state medical boards better police their own, rather than having cases escalate to criminal charges.

Deputy District Attorney John Niedermann told jurors during Tseng's trial that the doctor prescribed "crazy, outrageous amounts of medication" to patients who didn't need the pills.

Twelve of her patients died, but she was charged with just three murders because other factors were involved in the other deaths, including drugs prescribed by other doctors and a possible suicide.

Defense lawyer Tracy Green has said the 46-year-old doctor had been naive to prescribe so many medications and didn't think her patients would abuse them. Tseng's patients often hid addictions to painkillers and Tseng thought she was helping ease their pain, Green said.

After the sentencing, Tseng's 72-year-old mother wept outside the courtroom, saying 30 years is too much prison time.

"My heart is broken," she said.

The Drug Enforcement Administration says Tseng wrote more than 27,000 prescriptions over a three-year period starting in January 2007 — an average of 25 a day. She operated a storefront medical clinic with her husband in the Los Angeles suburb of Rowland Heights.

The first of her patients to die had received prescriptions from Tseng two days earlier for oxycodone, the anti-anxiety drug Xanax and the muscle-relaxer Soma, prosecutors said.

Vu Nguyen, 29, of Lake Forest, Steven Ogle, 25, of Palm Desert, and Joseph Rovero, 21, an Arizona State University student from San Ramon, died of overdoses between March and December 2009.

Ogle's mother, Desiree Ogle, said her son died eight hours after getting a methadone prescription from Tseng.

"She actually stopped his heart," Ogle said. "She froze time for us that day."