Naltrexone is an opiate antagonist approved by the Food and Drug Administration for use in alcohol and opiate agonist dependence. Naltrexone, at normal doses of 50 mg to 150 mg daily, has traditionally been used for the treatment of alcohol and opiate agonist addiction. A Cochrane review investigating the effects of naltrexone therapy on alcohol dependence found that it reduced the risk of heavy drinking by 83% and decreased drinking days by 4% compared to placebo. Additionally, using fillers such as calcium carbonate during compounding can reduce absorption of naltrexone, thereby affecting the pharmacokinetic profile, and should be avoided. Instead, inactive fillers such as Avicel®, sucrose, or lactose should be used in compounding. These immune, inflammatory, and opioid effects are key in managing the pathophysiology and progression of diseases such as multiple sclerosis, Crohn’s disease, sarcoidosis, fibromyalgia, complex regional pain syndrome, painful diabetic neuropathy, autism, infections, and cancer.