Naltrexone
"I filtered through these comments to see how many people had the same effect as I did. Literally day one. I have been drinking almost daily for 20+ years. After the first dose I had no craving. I drank a glass of wine just to see what would happen. It was fine, I finished it, but had no desire for another one!  That never happens. It almost seems too good to be true. It is remarkable that this drug is not used more for alcohol dependence. No doubt because it is generic and a big pharmaceutical company doesn't promote it."