The medication is mostly used to treat obesity, but can be used to treat addictions such as smoking.
It works as an appetite suppressant, and also apparently increases the levels of HDL - the good cholesterol. But it also comes with side effects. If you google the drug you'll likely find some information on its efficacy.
Does your friend need to resort to medication? Has she tried reducing her food intake, eating healthier foods and exercising more?
Acomplia (Rimonabant) - Technical Information