Alcohol Use Disorder (AUD) is a complex, treatable medical condition. Effective intervention often involves medication-assisted treatment (MAT), which significantly improves outcomes for many individuals seeking recovery. The two most common non-aversive options approved by the U.S. Food and Drug Administration (FDA) are acamprosate and naltrexone. These medications target the underlying physical and chemical changes in the brain caused by chronic alcohol consumption.
Acamprosate: Restoring Chemical Balance
Acamprosate (brand name Campral) is an FDA-approved medication used to help maintain abstinence from alcohol in patients with AUD. Its mechanism of action involves stabilizing chemical signaling in the brain altered by long-term heavy drinking. Acamprosate regulates the balance between the brain’s main excitatory and inhibitory neurotransmitters: glutamate and gamma-aminobutyric acid (GABA). Chronic alcohol use causes an overactive glutamate system and a suppressed GABA system, leading to psychological discomfort and anxiety during withdrawal. Acamprosate reduces this hyperexcitability, easing discomfort and reducing the psychological craving that can lead to relapse. It is typically taken as an oral tablet three times daily. It is most commonly prescribed after detoxification, once a person has achieved abstinence, to support long-term sobriety.
Naltrexone: Modifying the Brain’s Reward System
Naltrexone is an FDA-approved medication for AUD that fundamentally alters how the brain processes alcohol. It functions as an opioid antagonist, binding to opioid receptors, particularly the mu-opioid receptor. When alcohol is consumed, it causes the release of endorphins, which bind to these receptors and create pleasure or euphoria. By occupying these receptors, naltrexone blocks this reinforcing effect of alcohol, reducing the reward associated with drinking. This interruption reduces cravings and the desire to drink heavily. Naltrexone is available as an oral tablet taken once daily, or as an extended-release injectable form (Vivitrol) administered monthly. Naltrexone can be started while a patient is still drinking, offering a path to reduce heavy drinking before full abstinence is achieved.
Practical Differences in Usage and Side Effects
The application of acamprosate and naltrexone depends on a patient’s current drinking status and medical history. Naltrexone can be initiated while a patient is actively drinking, making it an option for those not ready for total abstinence. Acamprosate, conversely, is indicated for the maintenance of abstinence and is most effective when started after a person has stopped drinking.
The medications have distinct contraindications based on how they are processed by the body. Naltrexone is metabolized by the liver, so it must be avoided in individuals with severe liver impairment. Because it is an opioid antagonist, naltrexone is also contraindicated for anyone taking opioid pain medications or who has an active opioid use disorder, as it can precipitate severe withdrawal. Acamprosate is excreted through the kidneys and is contraindicated for patients with severe kidney impairment.
Patients generally tolerate both medications well, but they have different side effect profiles. Naltrexone’s most frequently reported side effects are gastrointestinal upset, nausea, and headache. For acamprosate, the most common side effect is diarrhea, along with potential issues like insomnia and anxiety. The choice between the two requires weighing the dosing schedule, required abstinence status, and potential side effects against the patient’s health profile and recovery goals.
Medication’s Role in Comprehensive AUD Treatment
Medication-assisted treatment (MAT) is an integrated approach to managing AUD, not a standalone solution or a simple cure. These medications address the biological aspects of dependence, such as reducing cravings and stabilizing brain chemistry, providing a foundation for psychological recovery.
The effectiveness of MAT is significantly enhanced when combined with psychosocial support. Comprehensive treatment involves counseling, behavioral therapies like Cognitive Behavioral Therapy (CBT), and mutual support groups. Pharmacological support manages physical urges and distress, allowing the individual to engage fully with the therapeutic process and develop coping strategies. MAT is a crucial tool that improves treatment retention and overall outcomes.