Naltrexone is a medication approved to treat both Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD) by working on receptors in the brain. While Naltrexone does not cause an acutely toxic reaction, such as the severe nausea and vomiting associated with Disulfiram, drinking alcohol is strongly discouraged. Continuing to drink significantly undermines the treatment goals and works against the medication’s therapeutic purpose of helping individuals reduce or stop alcohol consumption.
How Naltrexone Affects Alcohol Consumption
Naltrexone functions as an opioid receptor antagonist, blocking specific receptors in the central nervous system. Alcohol consumption stimulates the release of natural chemicals called endorphins. These endorphins bind to mu-opioid receptors, triggering a surge of dopamine in the brain’s reward pathway. This neurochemical cascade creates the pleasurable, reinforcing feeling that drives repeated alcohol consumption.
The medication reduces alcohol consumption by competitively binding to these mu-opioid receptors with a higher affinity than the naturally released endorphins. By occupying these receptors, Naltrexone prevents the endorphins from activating them, blocking the associated euphoric effects. This action diminishes the motivation to drink heavily and reduces the craving for alcohol over time, breaking the positive association between drinking and pleasure.
Naltrexone’s action is purely on the brain’s reward system and has no impact on the physical process of intoxication. The drug does not affect the blood alcohol concentration or the rate at which the body metabolizes alcohol. If a person drinks while on Naltrexone, they will still experience physical effects such as impaired coordination, slowed reaction time, and slurred speech. The medication only blunts the pleasurable, reinforcing “high” that alcohol normally provides.
Immediate Safety Concerns and Adverse Effects
Combining alcohol with Naltrexone introduces health risks. One significant concern is the potential for increased strain on the liver. Naltrexone itself carries a known, though rare, risk of hepatotoxicity, or liver damage, particularly if taken at doses higher than recommended.
When Naltrexone is combined with heavy alcohol use, the liver is subjected to a dual burden of metabolizing both the medication and the alcohol. This combined stress may increase the risk of liver enzyme elevations and potential injury. Patients should look out for symptoms like persistent nausea, severe abdominal pain, or jaundice, as these can be signs of serious liver issues.
A behavioral risk associated with drinking on Naltrexone is compensatory drinking. Because the medication blocks the rewarding effects of alcohol, some individuals may attempt to “drink through” the medication by consuming excessive amounts to achieve the familiar euphoric state. This can lead to dangerously high blood alcohol levels, increasing the risk of acute alcohol poisoning, blackouts, or severe intoxication, even though the perceived pleasure is diminished.
Combining alcohol with the medication can also exacerbate Naltrexone’s common side effects, including nausea, headache, dizziness, and vomiting. Alcohol can intensify these gastrointestinal and neurological symptoms, leading to greater discomfort and potentially poor adherence to the medication regimen.
Treatment Differences: Oral Naltrexone vs. Extended-Release Injection
Naltrexone is available in two primary forms for the treatment of AUD: a daily oral tablet and a monthly extended-release intramuscular injection. The oral tablet requires a person to take a pill once a day, typically at a 50 mg dose. This form offers flexibility, but it relies completely on the patient’s consistent adherence to the daily schedule, which can be a challenge for those struggling with active alcohol use disorder.
The extended-release injectable form, often known by the brand name Vivitrol, is administered once a month by a healthcare provider. This single injection releases the medication slowly over a four-week period, ensuring continuous therapeutic levels in the patient’s system. The injectable provides a reliable method of medication adherence for the full month.
Studies suggest that both the oral and injectable forms are similarly effective in reducing heavy drinking days. The injectable form removes the daily decision point of taking the medication, providing a consistent blockade of the opioid receptors, which is a logistical benefit for many patients. The oral form, by contrast, may be preferred by those who want the option to temporarily stop the medication if necessary for specific medical procedures requiring opioid pain relief.
When to Consult a Healthcare Professional
Regular communication with a prescribing physician is necessary for patient safety. Routine monitoring is required because Naltrexone is metabolized by the liver. Healthcare providers often recommend blood work to check liver function tests (LFTs), such as AST and ALT levels, at baseline and periodically (sometimes every three to six months), to monitor for potential hepatotoxicity.
Patients must immediately contact their healthcare professional if they experience symptoms suggesting liver injury. These symptoms include yellowing of the skin or eyes (jaundice), dark urine, persistent nausea or vomiting, or severe pain in the upper right side of the abdomen. While Naltrexone is generally safe, these signs warrant prompt medical evaluation and a potential change in the treatment plan.
If an individual experiences a lapse in recovery and drinks alcohol while on the medication, honesty with the prescribing physician is essential. This allows the doctor to evaluate the patient’s well-being, reassess treatment compliance, and adjust the therapeutic approach. Adjustments may include increasing counseling or switching between the oral and injectable forms of the drug to support long-term recovery goals.