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, will plead not guilty, public defender Thomas Thornton said. Kraynak treats people in a small part of Pennsylvania where they don't have doctors, 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.

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.