The addiction treatment medication buprenorphine was found in actor Philip Seymour Hoffman’s apartment, along with 50 bags of heroin and a variety of prescription drugs, according to New York City detectives. Hoffman died Sunday in an apparent heroin overdose.

Addiction medications such as buprenorphine can be very useful for treating heroin addiction, Dr. Jason Jerry, a professor of medicine with the Cleveland Clinic’s Alcohol and Drug Recovery Center, told ABC News. “Only 10 to 20 percent of patients who are completely detoxed and off of everything manage to stay clean for an extended period of time,” he said. “But the research shows that about 60 to 70 percent of people who use medications like buprenorphine or methadone are still in treatment after one year.”

He noted buprenorphine can be abused. The medication can be habit-forming, and can cause severe breathing difficulties when used in the wrong combination with other drugs, Jerry said.

The New York Times reports four people were arrested with more than 350 bags of heroin as part of the investigation into Hoffman’s death. Police said preliminary tests of the heroin found in his apartment did not contain fentanyl, a synthetic opiate tied to 22 recent fatal overdoses in Pennsylvania.