(CNN) - A Pennsylvania doctor charged with causing the deaths of five patients by unlawfully prescribing opioids surrendered his license to prescribe controlled substances at a federal court hearing Friday, officials said.
Dr. Raymond Kraynak -- whom prosecutors say prescribed nearly 3 million doses of opioids from January 2016 to July -- was released from custody Friday after posting a $500,000 bond, the US attorney's office for the Middle District of Pennsylvania said.
Kraynak awaits trial at a date yet to be determined.
Kraynak, 60, of Mount Carmel, was arrested Thursday. He is accused of, among other things, causing five deaths of patients between 2013 and 2015 by "unlawfully distributing and dispensing controlled substances" to them, according to the US Justice Department.
Prosecutors also allege that Kraynak, between 2005 and 2016, prescribed opioids "without a legitimate medical purpose' and "without conducting a proper medical examination," the US attorney's office said.
He is accused of failing to verify patients' medical complaints adequately and patients' risk of abuse before prescribing the drugs, the prosecution said.
Kraynak, who had offices in the central Pennsylvania communities of Mount Carmel and Shamokin, pleaded not guilty in an initial court appearance Thursday, prosecutors said.
Kraynak treated people in a small part of Pennsylvania where doctors are scarce, public defender Thomas Thornton said.
"At this point, we really haven't had a chance to see the evidence against him," his attorney said. "We're more concerned about his patients right now."
The US attorney's office alleges that Kraynak was the top prescriber in the state for opioids, writing ones for about 2.7 million doses of oxycodone, hydrocodone, oxycontin and fentanyl within 19 months. Those prescriptions were written for about 2,838 patients.
"The sheer number of pills prescribed in this case is staggering," US Attorney David Freed said in a statement. "Death or serious injury was the inevitable result of this defendant's conduct."
Kraynak is facing 19 charges, including five counts of the unlawful distribution and dispensing of a controlled substance resulting in death, 12 counts of prescribing controlled substances outside the usual course of professional practice and two counts of maintaining drug-involved premises at his offices.
It's not unprecedented for a doctor to be charged with causing the death of a patient through prescriptions. There have been similar cases in the past several years where doctors were held accountable in the deaths of patients who overdosed on opioid painkillers that had been prescribed.
In 2015, a doctor in Southern California was convicted of second-degree murder for the overdose deaths of three patients. She was sentenced to 30 years to life in prison.
In the Kraynak case, the government seeks the forfeiture of two medical offices, his medical license and $500,000, according to a DOJ statement announcing the indictment.
If convicted, Kraynak faces a mandatory 20 years to life in prison for each of the counts involving the five patients. The other 14 charges are each punishable by up to 20 years in prison.
The charges were the result of an investigation by the Drug Enforcement Administration, with assistance from state and local police.
Kraynak has a license in osteopathic medicine and had come to attention of the state board for his prescription practices. In 2012, he agreed to complete a medical course after prescribing large amounts of "various controlled substances" to seven patients from January 2007 through June 2008. The record does not identify what he had prescribed. The State Board of Osteopathic Medicine fined Kraynak $2,500.
The United States is in the throes of an opioid epidemic as more Americans have become dependent or abuse prescription pain pills and street drugs. More than 63,600 lives were lost to drug overdose in 2016, marking the most lethal year yet of the drug overdose epidemic, according to a report released this week.