Naltrexone is an opioid antagonist typically used at standard, higher doses (e.g., 50 mg) to treat opioid and alcohol dependence. Low Dose Naltrexone (LDN) refers to significantly lower daily doses, generally ranging from 0.5 mg to 4.5 mg. These low doses are thought to have immunomodulatory and anti-inflammatory effects rather than full, sustained opioid receptor blockade.