Naltrexone binds to opioid receptors in the brain and blocks the effects of opiate drugs that would otherwise make the user feel high. Naltrexone is a non-addictive medicine that blocks the opiate receptors in a person’s brain, which means patients don’t crave drugs or alcohol when they’re taking it. And if they happen to relapse, the medicine prevents them from feeling high. This effect deters individuals from relapsing because the drug no longer produces rewarding effects. Naltrexone has also been shown to be effective in alcohol detox. In both cases it can help to reduce cravings.