Sibutramine is a member of a modern group of drugs called SNRI's, which includes many other drugs such as milnacipran, duloxetine and venlafaxine. Most of the compounds in this group are used as antidepressants, and to start with, sibutramine was investigated for its potential properties as an antidepressant. When a serendipitous discovery showed that Sibutramine was very effective in aiding weight loss, development proceeded in this direction, leading to Sibutramine being one of the leading weight loss drugs on the market.