A Medway doctor is facing charges that he wrote fraudulent narcotics prescriptions, Middlesex District Attorney Marian Ryan said. Prosecutors say Nicholas Pacella, 50, wrote seven oxycodone prescriptions for a woman who was not his patient between June 2007 and June 2008. The woman then filled the prescriptions using her private health insurance, and the two allegedly shared the drugs, according to prosecutors. Pacella pleaded not guilty at his arraignment in Middlesex Superior Court Wednesday to two counts of filing a false insurance claim and one count of larceny under $250, prosecutors said.Lauren Dezenski can be reached at email@example.com. Follow her on Twitter @LaurenDezenski.