SAN FRANCISCO (CBS SF) — A San Mateo County doctor has been indicted on federal charges of unlawful distribution of opioids and health care fraud, according to authorities.

A federal grand jury indicted 67-year-old Timothy Mulligan of Santa Clara, who practices in San Mateo County, for allegedy prescribing opioids outside the scope of professional practice as well as the fraud charges. The charges were announced Tuesday by U.S. Attorney David L. Anderson and Drug Enforcement Administration Special Agent in Charge Daniel C. Comeaux.

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According to the indictment, Mulligan issued an unusually high volume of prescriptions for potent opioids such as fentanyl. According to a state government database, from about August 2014 through June 2018, Mulligan issued more than 9,000 prescriptions for opioids to more than 250 patients.

The indictment alleges Mulligan predominantly prescribed the strongest strength dosages when prescribing fentanyl, oxycodone, and hydrocodone and in some instances prescribed opioids in quantities that significantly exceeded generally accepted daily quantities for the drugs.

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Because of the unusual pattern and volume of prescriptions by Mulligan, some pharmacies declined to fill them or restricted the types of Mulligan’s prescriptions that they would fill, according to the indictment.

In addition, people who obtained the unlawful prescriptions from Mulligan used private insurance or Medi-Cal to pay for office visits or for the drugs, while others paid with cash. As the indictment alleged, insurance companies and Medi-Cal would not have paid the claims had they known the prescriptions were not medically necessary or were over-prescribed.

Mulligan’s next appearance in federal court was scheduled for April 29.

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If convicted of unlawfully distributing opioids, Mulligan faces a maximum sentence of 20 years in prison and a $1,000,000 fine, while a health care fraud conviction would have him facing a 10-year prison term and $250,000 fine for each count.