Its overall benefit has been described as "modest".Acamprosate may work better than naltrexone for eliminating alcohol abuse, while naltrexone may decrease the desire for alcohol to a greater extent.The Sinclair method is a method involving opiate antagonists such as naltrexone to treat alcoholism. The person takes the medication once, about an hour before consuming alcohol, to curb the urge to drink. The opioid antagonist is thought to block the positive reinforcement effects of alcohol and may assist the person to stop or reduce their drinking. Opioid use
Long-acting injectable naltrexone is an opioid receptor antagonist, blocking the effects of heroin and other opioids, and decreases heroin use compared to a placebo. Unlike methadone and buprenorphine, it is not a controlled medication. It may decrease cravings for opioids after a number of weeks, and decreases the risk of overdose, at least during the time period that naltrexone is still active, though concern about risk of overdose for those stopping treatment remains. It is given once per month and has better compliance and effect for opioid use than the oral formulation.A drawback of injectable naltrexone as compared to methadone and buprenorphine is the requirement for a period of opioid abstinence before starting the medication, as the injection can otherwise cause sudden and intense opioid withdrawal. This "hurdle" is responsible for worse patient uptake with long-acting injectable naltrexone as compared with buprenorphine.
In one study, the majority of sexual offenders reported a strong reduction in sexual urges and fantasies which reverted to baseline once the medication was discontinued. Case reports have also shown cessation of gambling and other compulsive behaviors, for as long as the medication was taken. Available forms
Naltrexone is available and most commonly used in the form of an oral tablet (50 mg). Vivitrol, a naltrexone formulation for depot injection containing 380 mg of the medication per vial, is also available. Additionally, naltrexone subcutaneous implants that are surgically implanted are available. While these are manufactured in Australia, they are not authorized for use within Australia, but only for export. By 2009, naltrexone implants showed superior efficacy in the treatment of heroin dependence when compared to the oral form.When taken at much smaller doses, a regimen known as Low Dose Naltrexone (LDN), naltrexone may reduce pain and help to address neurological symptoms. Some patients report that LDN helps reduce their symptoms of ME/CFS, multiple sclerosis (MS), fibromyalgia (FMS), or autoimmune disease. Although its mechanism of action is unclear, some have speculated that it may act as an anti-inflammatory. LDN is also being considered as a potential treatment for Long COVID. Contraindications
Naltrexone should not be used by persons with acute hepatitis or liver failure, or those with recent opioid use (typically 7–10 days). Side effects
The most common side effects reported with naltrexone are gastrointestinal complaints such as diarrhea and abdominal cramping.