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.
Although primarily an oral drug taken in pill form, naltrexone implants, which are inserted into the lower abdominal wall under local anesthetic, have been used to treat opioid addiction and/or abuse/misuse. Implants release a controlled amount of naltrexone into the body and are effective for three to six months.