A Chicago psychiatrist was sentenced to nine months in prison Friday for taking nearly $600,000 from pharmaceutical companies in exchange for prescribing a certain drug to patients.

Dr. Michael J. Reinstein, 72, of Skokie, pleaded guilty last year to violating the federal Medicare and Medicaid Anti-Kickback statute, according to the U.S. Attorney’s Office. Along with the sentence, the agreement call for him to repay about $592,000.

Reinstein, who practiced psychiatry in the Uptown neighborhood since 1973, prescribed the Clozapine to thousands of elderly patients in area nursing homes and hospitals, federal prosecutors said. At one point in the early 2000s, he was the largest prescriber of Clozapine to Medicaid recipients in the county.

Clozapine is an anti-psychotic medication effective for treatment-resistant forms of schizophrenia. But it has potentially serious side effects for elderly patients, including a potentially deadly decrease in white blood cells, seizures and heart inflammation, according to prosecutors.

In exchange for writing the prescriptions, pharmaceutical companies paid the doctor consulting fess and entertainment expenses such as meals, sports tickets and all-expense-paid vacations, according to the statement.

Reinstein said in his plea agreement that he prescribed Clozaril, the brand-name version of Clozapine, for some time after the less-expensive, generic versions became available because the manufacturer paid him thousands of dollars, according to the statement.

In 2003, the deal with the manufacturer ended, and Reinstein agreed to switch patients to the generic version, but only after the manufacturers, Teva Pharmaceuticals USA and IVAX Pharmaceuticals, agreed to pay him a consulting fee and finance a Clozapine research study by a Reinstein-affiliated entity, according to prosecutors.

Between 2006 and 2011, Teva also paid $112,000 to an individual Reinstein “described as an important source of patient referrals.” The person was paid to enter white blood cell data into a national Clozapine registry, according to the statement.

Reinstein previously agreed to pay $3.79 million and Teva and IVAX paid $27.6 million to settle civil lawsuits.

Along with his prison sentence and forfeiture, he must complete 120 hours of community service.