An Oklahoma doctor is facing five counts of second-degree murder charges following the opioid overdose deaths of her patients.

Prosecutors charged osteopathic physician Regan Ganoung Nichols, 57, on Friday in Oklahoma County District Court. Oklahoma Attorney General Mike Hunter told reporters that Nichols prescribed trusting patients a “horrifyingly excessive” amount of opioid medications. “Nichols’ blatant disregard for the lives of her patients is unconscionable,” he said.

In all, Nichols allegedly prescribed more than 1,800 medically unnecessary opioid pills to the patients who died , according to a probable cause affidavit reported by the Associated Press. Three out of the five patients also received allegedly deadly combinations of painkillers, muscle relaxants, and anti-anxiety medications.

The charges are the latest in a new trend among authorities and law enforcement to target doctors as well as pharmaceutical companies for their role in a devastating nationwide epidemic of opioid abuse and overdoses. The Centers for Disease Control and Prevention estimate that 91 Americans die each day from the drugs. Opioids contributed to the deaths of 33,000 Americans in 2015, and overdoses have more than quadrupled since 2000, the agency notes.

In recent years, a string of charges has been brought against doctors for allegedly overprescribing opioids to patients and those suffering with addiction. In 2014, an Oklahoma City doctor pled guilty to eight counts of manslaughter for overprescribing opioid painkillers. In a notable case in Los Angeles, doctor Hsiu-Ying "Lisa" Tseng was convicted of second-degree murder for overprescribing opioids in order to make money, which caused the overdose deaths of three of her patients. She was sentenced to 30 years to life in prison

In Nichols’ case, investigators said that she “either didn’t know or didn’t care what she was doing,” the Washington Post reports.

In 2010, one of Nichols’ patients died six days after Nichols prescribed a total of 450 pills, including painkillers, muscle relaxants, and anti-anxiety drugs. Nichols prescribed another patient in February of 2012 with 240 pain and anti-anxiety pills despite not examining that patient since 2008. The patient died about a month later.

Investigators began looking into Nichols’ prescription habits in 2014; the five deaths she is charged with all occurred between 2010 and 2013. But as many as 10 of her patients have died of overdoses, The Oklahoman reports. In 2015, the Oklahoma State Board of Osteopathic Examiners placed her on probation for five years, which prevented her from prescribing more opioids.

If convicted of the current charges, Nichols faces at least 10 years in prison for each of the five counts. Nichols was released from jail on $50,000 bail Friday. She has not been reached for comment by media, and a phone number for her at Sunshine Medical Center was disconnected. This story will be updated if she releases a statement.