Narcotics Anonymous is a 12-step program adapted from AA. The primary difference between the two is that NA is more inclusive with respect to addiction to any mood-altering substance. Cocaine Anonymous (CA) is a smaller group geared specifically to cocaine addiction, as the name implies. NA and CA, like the many other 12-step programs AA has spawned, adhere to the same philosophy and beliefs as AA. The underlying belief is that most aspects of chemical addiction are transcendent rather than specific to any particular drug.
Source: The National Institute on Alcohol Abuse and Alcoholism (http://www.niaaa.nih.gov)