It can be very difficult to get a loved one to even admit that they have a drug problem, let alone take the steps required to overcome drug addiction. What drug(s) your loved one is having a problem makes a difference too. If you’re referring to smoking you probably won’t be able to do anything to stop it. If you’re referring to alcohol, an intervention is a common method to make your loved on realize they are hurting themselves and their family. Interventions can be used for other drugs as well, although sometimes more drastic steps are required for drugs such as heroin.
The best thing you can do, at least to begin with, is to discuss the drug problem with other people who know and care for the person with the drug problem. You are going to want to show this person that there are many people who care about them and want them to kick the drug habit they have created. Talking with a professional, such as a doctor, is also helpful. They can give you contact information for drug rehabilitation centers, or other places that may be needed to help break the drug habit.
This link will give you additional information.
http://www.listenmagazine.org/listwinner/listen/drugs.asp