<unk> (oral) is an opioid antagonist that is FDA approved for the treatment of alcoholism and opioid dependence.   Common adverse reactions include abdominal cramps, abdominal pain, nausea, arthralgia, myalgia, insomnia, headache, fatigue, anxiety, and nervousness.
Naltrexone 
Methadone 
Buprenorphine 
Guanfacine
Nabilone
Atomoxetine
Vilazodone
Levomethadone