The autonomic nervous system is the part of the nervous system that controls muscles of internal organs (such as the heart, blood vessels, lungs, stomach, and intestines) and glands (such as salivary glands and sweat glands).
Naltrexone is also used to reduce cravings for alcohol. Scientists are unsure how it works in relation to alcohol but it has been shown to reduce desire and cravings by blocking the same receptors that create feelings of pleasure when opioids are taken.
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.