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.
Physicians are advised that 5 to 15% of patients taking Naltrexone for alcoholism will complain of non-specific side effects, chiefly gastrointestinal upset. Prescribing physicians have tried using an initial 25 mg dose, splitting the daily dose, and adjusting the time of dosing with limited success.