A federal judge sentenced a former salesman for a Honolulu pharmacy to 18 months in prison Monday for defrauding the Hawaii Medical Service Association of thousands of dollars by submitting forged prescriptions to pad his commissions.

In addition to the prison term, Senior U.S. District Judge Susan Oki Mollway ordered Jeremy Imai to repay HMSA $59,530 he collected through his employer in unearned commissions. Mollway did not impose a fine.

Imai, 40, of Aiea, pleaded guilty in January to health care fraud.

He admitted that between June and August 2016, he submitted to his employer forged prescriptions for pain creams, patches and compounds for HMSA members, including his minor son. The pharmacy, in turn, billed HMSA $165,908. That was for prescriptions for one doctor.

Imai admitted that he submitted forged prescriptions for a second doctor, but he is not having to pay additional restitution because the doctor cannot discern which of the prescriptions attributed to him during that period are fraudulent.

Assistant U.S. Attorney Kenneth Sorenson described Imai’s scheme as well orchestrated and well executed, and asked Mollway to impose a longer sentence and a fine. He said HMSA is not the only victim because it passes on losses to its members in the form of higher premiums.

“What I’ve done is not lost on me, the severity of it,” Imai told Mollway.

He said his current job in insurance has him dealing directly with clients.