Naltrexone hydrochloride, known by brand names ReVia® and Vivitrol®, is a type of medication that acts as an opioid antagonist. This means it is able to impair or block the effects opioids have on the body. Some of the opioids naltrexone blocks are heroin, morphine, and codeine. Essentially, this drug works by blocking the parts of the brain that cause someone to feel euphoric or good when exposed to narcotic drugs. It can be used for fighting dependency on opioids.
Naltrexone may also be used in the treatment of alcoholism. So far, no one knows for sure what makes the medication so effective in the treatment of alcoholism. However, patients report a reduction in the urge to drink. Also, the medication may stop an alcoholic from drinking more and more if he deviates from his recovery and has an alcoholic beverage.
Generally speaking, naltrexone can block effects of opioids very quickly after taking just one dose. Effects with alcoholism may occur fairly soon as well. Some experts assert that the drug is most effective when combined with other treatment mechanisms, such as therapy. It is not addictive, and it doesn't cause psychological effects; most people don't feel as if they are high on drugs when they are on it. Additionally, the medication is not supposed to interfere with types of pleasure that don't come from opiate drug use or from the consumption of alcoholic beverages.
Naltrexone causes side effects in only a small amount of the people who receive it. When side effects do occur, they tend to be fleeting and mild. Some people on naltrexone may experience such things as nausea, anxiety, fatigue, and headaches; others on the medication may experience dizziness and insomnia. Though most people can take naltrexone without any serious side effects, there is the possibility that the drug will be toxic to the liver. For this reason, patients may have to undergo blood tests to evaluate liver function before starting treatment as well as during treatment.
There are some people who should not take naltrexone, such as pregnant women. Some people with liver or kidney damage may not be good candidates for using this medication. However, this depends on the level of damage and the overall health of the patient. Additionally, it may not be used in patients who cannot abstain from drinking alcoholic beverages for at least five days before beginning treatment. Likewise, those who are addicted to opiates must be able to abstain for at least seven full days before they start taking the medication.