What drug does Bowen take to help him reduce his opiate dependency as noted in the memoir, The World According to Bob: The Further Adventures of One Man and His Streetwise Cat?

Subutex is the drug that Bowen has been taking to help him reduce his opiate dependency. After roughly six months on the drug, Bowen's counselor tells him he is issuing his final prescription. Bowen is shocked and terrified of stopping the subutex, unconvinced that he will be able to survive clean. The morning after taking the final subutex tablet, however, Bowen wakes up feeling strong and energized. The end of the subutex marks Bowen's full recovery.