In my experience, when using naltrexone for alcohol dependence, patients tend to drink more alcohol. I thought this was to compensate for the loss of enjoyment from alcohol from naltrexone treatment.

I read somewhere online that a some people get severe nausea and projectile vomiting when combining low dose naltrexone and alcoholic beverages.

Here is a result from Drugs.com:

Drug interactions for the following 2 drug(s):

naltrexone ↔ ethanol

Applies to: naltrexone, Alcohol (contained in alcoholic beverages) (ethanol)

GENERALLY AVOID: Coadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin.

MANAGEMENT: The use of naltrexone in combination with other potentially hepatotoxic agents (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; endothelin receptor antagonists; interferons; nucleoside reverse transcriptase inhibitors; thiazolidinediones; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, HMG-CoA reductase inhibitors, and niacin; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice) is generally not recommended unless the potential benefit outweighs the risk. Patients treated with naltrexone should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, light-colored stools, and jaundice. Periodic monitoring of hepatic function is advisable.