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.
Other data suggest that doubling the dose of naltrexone provides blockade for 48 hours, and tripling the dose of naltrexone provides blockade for about 72 hours. Clinical studies indicate that 50 mg of naltrexone will block the pharmacologic effects of 25 mg of i.v. administered heroin for periods as long as 24 hours. Other data suggest that doubling the dose of naltrexone provides blockade for 48 hours, and tripling the dose of naltrexone provides blockade for about 72 hours.