Naltrexone sold under the brand names ReVia and Vivitrol among others, is a medication primarily used to manage alcohol or opioid dependence. An opioid-dependent person should not receive naltrexone before detoxification. It is taken by mouth or by injection into a muscle. Effects begin within 30 minutes. A decreased desire for opioids, though, may take a few weeks.
Side effects may include trouble sleeping, anxiety, nausea, and headaches. In those still on opioids, opioid withdrawal may occur. Use is not recommended in people with liver failure. It is unclear if use is safe during pregnancy. Naltrexone is an opioid antagonist and works by blocking the effects of opioids, both those from inside and outside the body.
Naltrexone was first made in 1965 and was approved for medical use in the United States in 1984. As of 2017, the wholesale cost of tablets is about US$0.74 per day in the US. The extended-release injections cost about $1,267 per month ($41.20 per day). Naltrexone, as bupropion/naltrexone, is also used to treat obesity.
Long-acting injectable Naltrexone decreases heroin use more than placebo. It has benefits over methadone and buprenorphine in that it is not a restricted medication.It may decrease cravings for opioids after a number of weeks, and decreases the risk of overdose. It is given once per month and has better compliance than the oral formulation.
A 2011 review found insufficient evidence to determine the effect of Buy Naltrexone Online taken by mouth in opioid dependence. While some do well with this formulation, it must be taken daily, and a person whose cravings become overwhelming can obtain opioid intoxication simply by skipping a dose. Due to this issue, the usefulness of oral naltrexone in opioid use disorders is limited by the low retention in treatment. Naltrexone by mouth remains an ideal treatment for a small number of people with opioid use, usually those with a stable social situation and motivation. With additional contingency management support, naltrexone may be effective in a broader population.