PROVIDENCE, R.I. (Reuters) - A Rhode Island doctor was sentenced on Friday to more than four years in prison after admitting he took kickbacks from Insys Therapeutics Inc to prescribe its fentanyl-based cancer pain drug to people who did not suffer from the condition.

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Jerrold Rosenberg, 63, was sentenced by U.S. District Judge John McConnell in Providence, Rhode Island, who said the doctor effectively sold his medical license to a pharmaceutical company seeking to boost its profits.

McConnell said patients were put at risk by Rosenberg, who has admitted the $188,000 Insys paid him in the form of speaker fees were a factor in his decision to write prescriptions for the medication, Subsys.

The U.S. Food and Drug Administration has approved the powerful opioid-based spray for use only by people with cancer, but prosecutors said Rosenberg prescribed it to a wider range of patients with chronic pain.

“Greed has no role in that sacred relationship that exists between a doctor and a patient,” McConnell said in sentencing Rosenberg to 51 months in prison.

Three patients spoke at the doctor’s sentencing including Daisy Medina, who said she became addicted to Subsys. Medina said when she asked Rosenberg to take her off it, he told her to “stop being a baby.”

“I had never touched drugs,” she said. “He made me a junkie.”

Rosenberg, who pleaded guilty in October to healthcare fraud and conspiracy to receive kickbacks, said he took precautions to help his patients. “That said, I’ve obviously failed some patients,” Rosenberg said.

Rosenberg, who must also pay $754,736 in restitution, is among several medical practitioners and former Insys executives and employees who have faced criminal charges related to Subsys.

Federal prosecutors in Boston have accused seven former executives and managers at Insys, including billionaire founder John Kapoor, of participating in a scheme to bribe doctors to prescribe Subsys and to defraud insurers into paying for it.

Prosecutors said Kapoor, ex-Insys Chief Executive Michael Babich and others schemed to bribe medical practitioners, paying them using sham speaker programs ostensibly meant to educate healthcare professionals about Subsys.

They have pleaded not guilty. Chandler, Arizona-based Insys has said it may need to pay at least $150 million to resolve the U.S. Justice Department’s probe.

Rosenberg received speaker fees from 2012 to 2015. He also fraudulently indicated his patients had cancer when they did not in order to secure insurance approvals for Subsys, prosecutors said.