Huangpu District People's Court has sentenced a drug addict to seven years in prison for selling the methadone he received in a public drug treatment program to other addicts, the court said Thursday.

The case was one of 19 that the district court dealt with from July to September that involved addicts reselling their drug treatment medication, according to a court press release.

There are about 14 community hospitals in the city, including one in Huangpu district, that treat drug addicts with methadone, said Tang Zhengming, a press officer for the Huangpu District People's Court.

The defendant, surnamed Chen, 35, was charged with drug trafficking for selling the methadone, which is a synthetic opioid used to ease the withdrawal symptoms of patients recovering from an addiction to drugs such as heroin, according to the press release.

Chen, who worked as a hotel security guard, began taking illegal drugs when he was 16 years old, the court said. He has received administrative punishment several times for drug use.

Over the last few years, Chen has been receiving treatment at a community hospital in Huangpu district. The hospital treats recovering drug addicts by giving them a specific amount of methadone each day to take the edge off their withdrawal symptoms.

Chen began to save some of the methadone after he figured out that he didn't need his entire daily dose. He did this by only swallowing part of liquid methadone he received from the doctors. He spit the rest into a bottle that he took with him out of the hospital.

When he collected enough of the drug, he sold it to other addicts on the street.

Police arrested Chen on June 16 after he tried to sell 313.56 grams of methadone to a drug addict for 300 yuan ($49).

The court blamed the methadone trafficking problem on lax supervision by the doctors who prescribe and administer the drug.

It advised treatment facilities to assign at least two doctors to supervise patients while they are taking the drug. It also advised doctors to do a better job prescribing an appropriate amount of methadone to their patients.

Under the city's current regulations, opioid addicts over 20 years old with local residency or a residence permit for more than six months can receive methadone treatment at a community hospital.