Medications used in the treatment of addiction differ widely from each other because addiction is such a broad term, and the important aspect to know and understand first is what substance the person is addicted to. For that reason, medications used to treat addiction can only be categorized according to substance abused.
A person who is addicted to opiates might be abusing anything from heroin to methadone to morphine to dilaudid to oxycontin to percocet, Vicodin, or codeine.
Medications used to treat opiate addiction act on the same areas of the brain that the opiates act on—the so-called opioid receptors in the brain—and they block their ability to uptake opiates without perpetuating the addiction itself. Drugs including methadone and buprenorphine work this way. As partial opiates themselves, they can inhabit the receptors without completely sending the addict into full blown withdrawal, which can be dangerous. That is what happens when a patient is given Naltrexone, a drug that directly blocks the activity of opiates like morphine or heroin. This is the kind of medication only given to addicts who have already gone through detoxification.
Sometimes, a benzodiazepene like clonapin will be used to blunt the intial symptoms of withdrawal in an addict.
The goal of many of these medications is to make the patient more amenable to behavioral treatments.
There are three FDA approved medications for the treatment of alcohol dependence:
Naltrexone: Mentioned above, this drug helps by inhibiting the rewarding effects of alcohol and by helping to blunt cravings. It can be effective in some patients and entirely ineffective in others.
Acamprosate: This medication is believed to help ease withdrawal symptoms and their effects, including insomnia, anxiety and other problems that not only make life miserable, but also make relapse more likely.
Disulfiram: Disulfiram blocks alcohol degradation in the body, causing acetaldehyde to accumulate, which creates a a very unpleasant reaction to alcohol that might feature flushing, nausea, and heart palpitations.
A pair of FDA approved medications are available to help people quit smoking:
Bupropion and varenicline. These medications work differently in the brain but both medications, when combined with psycho-social therapy, can help a person quit smoking.
Meanwhile, smokers and other tobacco users have available things suchas the nicotine patch, spray, gum, and lozenges—all of which work to replace the nicotine cravings created in the brain when a person stops smoking, since nicotine is the chief addictive substance in cigarettes.