Acamprosate is a prescription medication approved by the FDA to help people with alcohol use disorder stay away from alcohol after they have already stopped drinking. It works by reducing the persistent craving and discomfort that often lead back to drinking. It is not a treatment for acute alcohol withdrawal, and it is not a cure. It is one tool that some people use as part of a broader treatment plan.
What Is Acamprosate Used For In Alcohol Use Disorder?
Acamprosate is used to support abstinence in people who have already stopped drinking. The FDA approved it for this purpose, and it is one of a small number of medications with that specific indication.
The key word is maintenance. Acamprosate is not given to someone who is still drinking heavily or who is in the middle of withdrawal. It is started after a person has achieved abstinence, usually through medically supervised detox or a period of self-directed stopping. The goal is to help them stay stopped.
Alcohol use disorder is a chronic condition. For many people, the period right after quitting is the most fragile. The brain has adapted to heavy alcohol exposure over months or years, and those adaptations do not reverse overnight. Cravings, mood instability, sleep problems, and a heightened sensitivity to stress can persist for weeks or months. Acamprosate targets part of that biology.
It is not effective for everyone. Clinical trials show that it helps some people maintain abstinence longer than they would without it, but the effect is modest on an individual level. It works best when combined with counseling, behavioral therapy, or participation in a structured recovery program.
How Does Acamprosate Work in the Brain?
Acamprosate is thought to help restore balance to two major neurotransmitter systems that alcohol disrupts: glutamate and GABA.
Glutamate is the brain’s main excitatory signal. GABA is the main inhibitory one. When someone drinks heavily for a long time, the brain compensates by dampening GABA activity and ramping up glutamate activity to keep things stable. When alcohol is removed, that compensation remains in place. The result is an overactive, unbalanced brain state that contributes to withdrawal symptoms and, later, to cravings and relapse risk.
Acamprosate appears to modulate glutamate activity, particularly at certain receptor subtypes, and may also influence GABA signaling. The precise mechanism is not fully understood. What researchers believe is that by settling this hyperexcitable state, acamprosate reduces the background noise of craving and the discomfort of early abstinence.
One important clarification: acamprosate does not block the effects of alcohol the way naltrexone does. Naltrexone works on opioid receptors and reduces the reward a person gets from drinking. Acamprosate works differently. It does not make drinking unpleasant. It does not cause a reaction if someone drinks. It simply aims to reduce the drive to drink in the first place.
Who Is Acamprosate Prescribed For?
Acamprosate is typically considered for adults with moderate to severe alcohol use disorder who have stopped drinking and want to remain abstinent.
It may be a reasonable option for people who:
- Have completed medically supervised withdrawal and are no longer drinking
- Have struggled with repeated relapse driven by craving
- Cannot take naltrexone due to liver concerns, side effects, or other medical reasons
- Are already engaged in counseling or a recovery program
It is generally not used in people who are still actively drinking, because the evidence for benefit in that situation is limited. It is also not a standalone treatment. The clinical consensus, supported by treatment guidelines, is that medication works best alongside psychosocial support.
Acamprosate is not approved for adolescents. Data in younger populations is limited, and no established clinical guidance supports its use in that group.
How Is Acamprosate Taken?
Acamprosate is taken as a delayed-release tablet by mouth, usually three times a day with meals. The standard adult dose is 666 mg three times daily, which is the dose studied in the clinical trials that supported approval.
For people with significant kidney impairment, a lower dose is used. This is because acamprosate is cleared by the kidneys, and reduced kidney function means the drug can build up in the body. Kidney function is typically checked before starting treatment.
Taking it with food matters. The delayed-release coating is designed to release the medication at a certain point in the digestive tract, and food helps that process work as intended. Skipping meals or taking it on an empty stomach can affect absorption.
Acamprosate does not need to be tapered when stopping. Unlike some medications, it does not produce a withdrawal syndrome of its own.
What Does the Evidence Show About Effectiveness?
Clinical trials and systematic reviews generally support acamprosate as modestly effective for maintaining abstinence in alcohol use disorder. The pattern across studies is consistent: people taking acamprosate tend to stay abstinent longer and are more likely to remain abstinent over the treatment period compared to those taking a placebo.
The effect size is real but not dramatic. It is not a medication that makes relapse impossible. It shifts the odds somewhat in the person’s favor, and that shift matters most when combined with therapy and support.
Comparing acamprosate to naltrexone is complicated. Both are considered first-line options, and the evidence does not clearly show one is superior for everyone. Some studies suggest naltrexone may have a slight edge for reducing heavy drinking, while acamprosate may be somewhat better suited for maintaining complete abstinence. But these comparisons are not consistent across all trials, and treatment decisions are usually made based on the individual’s history, medical status, and preferences.
One non-obvious point: acamprosate is often underused. It is FDA-approved, generally well tolerated, and has decades of clinical data behind it. Yet many people with alcohol use disorder never receive a prescription for any medication. This gap between what the evidence supports and what happens in practice is widely recognized in addiction medicine.
What Are the Side Effects and Risks?
Acamprosate is generally well tolerated. The most common side effect is diarrhea. Other reported effects include nausea, stomach upset, headache, and mild dizziness.
Serious side effects are uncommon. In rare cases, mood changes or suicidal thoughts have been reported, and anyone starting the medication should be aware of that possibility and report it to their doctor.
Because acamprosate is cleared by the kidneys, it is used with caution in people with kidney disease. It is not recommended for people with severe kidney impairment. Kidney function should be assessed before and sometimes during treatment.
Acamprosate has not been shown to be harmful to the liver, which is one reason it is sometimes preferred over naltrexone in people with liver damage from alcohol. Naltrexone can be hard on the liver at higher doses, and acamprosate does not carry that concern.
There is no evidence that acamprosate interacts dangerously with alcohol if someone does drink while taking it. But drinking while on acamprosate defeats the purpose of treatment, and it should be discussed openly with a doctor rather than hidden.
How Does Acamprosate Compare to Other Medications?
Three medications are FDA-approved for alcohol use disorder: acamprosate, naltrexone (oral and injectable), and disulfiram. Each works differently and suits different situations.
| Medication | How It Works | Best Suited For |
|---|---|---|
| Acamprosate | Modulates glutamate and GABA signaling to reduce craving and support abstinence | People who have stopped drinking and want to stay abstinent |
| Naltrexone | Blocks opioid receptors, reducing the reward from drinking | People who want to reduce heavy drinking or prevent relapse |
| Disulfiram | Creates an unpleasant reaction if alcohol is consumed | People who are highly motivated and under supervision |
Disulfiram works on a different principle entirely. It does not reduce craving. It makes drinking physically unpleasant by interfering with how the body breaks down alcohol. It requires strict abstinence and commitment, and it is generally considered a second-line option for most people.
The choice between these medications is not one-size-fits-all. Some people try one, find it does not help, and switch to another. Others combine medications, though the evidence for combination therapy is more limited. A doctor familiar with addiction medicine can help sort through the options.
What Else Matters for Recovery?
Medication is one part of a larger picture. Alcohol use disorder is a chronic condition, and like other chronic conditions, it usually requires ongoing management rather than a single intervention.
Behavioral therapy, counseling, and peer support programs all have evidence behind them. They help people build skills, address underlying issues, and stay connected to support during difficult periods. Combining medication with these approaches tends to produce better outcomes than either alone.
It also helps to address co-occurring conditions. Anxiety, depression, trauma, and sleep disorders often overlap with alcohol use disorder. Treating only the drinking while ignoring these other issues makes sustained recovery harder.
Relapse is common and does not mean treatment has failed. It is a signal to reassess and adjust the plan. Many people try several approaches before finding what works for them.
Frequently Asked Questions
Is acamprosate a cure for alcohol use disorder?
No. Acamprosate is a medication that can help reduce craving and support abstinence, but it is not a cure. It works best as part of a broader treatment plan that includes counseling or behavioral support.
Can you drink alcohol while taking acamprosate?
Acamprosate is intended for people who have already stopped drinking, and drinking while taking it goes against the purpose of treatment. It does not cause a dangerous reaction with alcohol, but it also will not work as intended if drinking continues.
How long do you take acamprosate?
There is no fixed duration. Many clinicians recommend continuing for at least several months, and some people stay on it longer. The decision is usually based on individual progress and relapse risk.
What is the difference between acamprosate and naltrexone?
Acamprosate works on glutamate and GABA signaling to reduce craving and support abstinence, while naltrexone blocks opioid receptors to reduce the reward from drinking. Both are considered first-line options, and the choice depends on the person’s needs and medical history.
