Naltrexone is an opioid receptor antagonist used primarily in the management of alcohol dependence and opioid dependence. It is marketed in generic form as its hydrochloride salt, naltrexone hydrochloride, and marketed under the trade names Revia and Depade. In some countries including the United States, a once-monthly extended-release injectable formulation is marketed under the trade name Vivitrol. Also in the US, Methylnaltrexone Bromide, a closely related drug, is marketed as Relistor, for the treatment of opioid induced constipation.
Naltrexone should not be confused with naloxone (which is used in emergency cases of overdose rather than for longer-term dependence control) nor nalorphine. Both nalorphine and naloxone are full antagonists and will treat an opioid overdose, but naltrexone is longer-acting than naloxone (although neither is an irreversible antagonist like naloxazone), making naloxone a better emergency antidote.
Naltrexone helps patients overcome urges to abuse opiates by blocking the drugs’ euphoric effects. While some patients do well with the oral formulation, there is a drawback in that it must be taken daily, and a patient whose craving becomes overwhelming can obtain opiate euphoria simply by skipping a dose before resuming abuse.
The FDA approved Vivitrol, the long-acting version of naltrexone, on October 12, 2010 for the prevention of relapse to opioid dependence, following opioid detoxification. “This drug approval represents a significant advancement in addiction treatment,” said Janet Woodcock, M.D., director of the FDA’s Center Drug Evaluation and Research.[17]
Nora Volkow, M.D., Director of the National Institute on Drug Abuse (NIDA), stated that: “As a depot formulation, dosed monthly, Vivitrol obviates the daily need for patients to motivate themselves to stick to a treatment regimen - a formidable task, especially in the face of multiple triggers of craving and relapse. This new option increases the pharmaceutical choices for treating opioid addiction, and may be seen as advantageous by those unwilling to consider agonist or partial agonist approaches to treatment. NIDA is continuing to support research on Vivitrol's effectiveness in this country, including a focus on criminal justice involved populations transitioning back into the community.”[18]
The phase 3 clinical study upon which the FDA granted approval for Vivitrol in treating opioid dependence had an enrollment of 250. Primary outcome measures were percent of weekly urine tests that were negative for opioids and the length of the study retention during the double-blind period. The study began in June 2008 and was completed in November 2009.
Alkermes presented positive results from the phase 3 clinical study of Vivitrol for the treatment of opioid dependence at the American Psychiatric Association 2010 Annual Meeting in May 2010. The study met its primary efficacy endpoint and data showed that patients treated once-monthly with Vivitrol demonstrated statistically significant higher rates of clean (opioid-free) urine screens, compared to patients treated with a placebo, as measured by the cumulative distribution of clean urine screens (p<0.0002).[19] The results of the study are expected to be published soon.
Another option for the treatment of opiate addiction is the naltrexone implant, which may be surgically inserted under the skin. The implant provides a sustained dose of naltrexone to the patient, thereby preventing the problems which may be associated with skipping doses. It must be replaced every several months. Naltrexone implants are made by at least three companies, though none have been approved by the U.S. Food and Drug Administration (FDA) or the Australian Therapeutic Goods Administration.[20]
and if so will it work and help people get clean? How many would be necessary, 3? I have 14x 50mg. Can you break it in half or in quarters like how people do with Suboxone? And also, can you initially only take it for 3 days to get clean since it's 72 hours for your body to detox?
Glad we cleared that up. 
