How does Acamprosate work to help you stay sober? A plain-English explanation of its mechanism of action, how long it takes, and how it compares to other meds.
When you drink heavily for a long time and then stop, your brain doesn't just snap back to normal. It's stuck in a state of hyperexcitability — like a car engine still revving after you've taken your foot off the gas. That's where Acamprosate comes in.
Acamprosate (formerly sold as Campral) is one of three FDA-approved medications for alcohol use disorder. But unlike the other two — Naltrexone and Disulfiram — Acamprosate works by directly addressing the chemical imbalance that makes early sobriety feel so uncomfortable.
Here's how it works, explained without the medical jargon.
To understand Acamprosate, you need to understand what chronic drinking does to your brain chemistry. Your brain operates on a balance between two types of signals:
Alcohol enhances GABA (the calming side) and suppresses glutamate (the stimulating side). That's why drinking makes you feel relaxed.
But when you drink heavily for months or years, your brain adapts. It reduces its own GABA activity and ramps up glutamate to compensate. Your brain is trying to maintain balance despite the constant presence of alcohol.
When you suddenly remove the alcohol, your brain is left in an unbalanced state — too much glutamate, not enough GABA. Think of it like this: alcohol was pushing the brakes, and your brain responded by pressing harder on the gas. Now the brakes are gone, but the gas pedal is still floored.
This is why early sobriety often comes with:
This neurological discomfort is a major reason people relapse — not because they lack willpower, but because their brain chemistry is literally pushing them back toward alcohol.
Acamprosate is a structural analogue of GABA — meaning its molecular shape is similar to the GABA your brain naturally produces. But it doesn't simply boost GABA the way alcohol does.
Instead, Acamprosate works on the glutamate system. Specifically, it:
A simple analogy: Imagine your brain's thermostat is broken after years of drinking. It's stuck on "too hot" (too much excitatory activity). Acamprosate helps recalibrate the thermostat so your brain can cool down to a comfortable temperature on its own.
Importantly, Acamprosate does not:
It simply makes sobriety more comfortable by reducing the neurological distress that drives cravings.
Acamprosate doesn't produce an immediate, noticeable effect like a painkiller or anti-anxiety medication. Most patients don't "feel" it working in the moment. Instead, its effects build over time.
Here's what to expect:
Clinical trials measured outcomes over 3 to 12 months, and the benefits were most clear in patients who took it consistently throughout the study period. Consistency matters — taking all three daily doses as prescribed gives Acamprosate the best chance to work.
Acamprosate has a relatively long half-life of about 20 to 33 hours. However, its bioavailability is low (around 11%), which is why it needs to be taken three times a day at a relatively high dose (two 333 mg tablets per dose).
The medication is not metabolized by the liver — it is eliminated entirely through the kidneys unchanged. This is why kidney function matters and why Acamprosate is contraindicated in people with severe kidney disease.
If you stop taking Acamprosate, it clears from your system within a few days. There is no withdrawal effect from stopping Acamprosate — it is not habit-forming and does not create physical dependence.
There are three FDA-approved medications for alcohol use disorder. Each works differently:
Naltrexone is an opioid receptor antagonist. It blocks the "reward" feeling you get from drinking alcohol. If you drink while on Naltrexone, you don't feel the same pleasure, which helps reduce the motivation to drink.
Acamprosate takes a different approach — it doesn't block the effects of alcohol. Instead, it reduces the discomfort of not drinking by calming the hyperexcited brain chemistry of early sobriety.
Some doctors prescribe both medications together. In clinical practice, this combination is sometimes used even though Naltrexone can slightly increase Acamprosate blood levels.
Disulfiram (Antabuse) works through aversion — if you drink while taking it, you'll experience intense nausea, vomiting, flushing, and other unpleasant symptoms. It's a deterrent: you avoid alcohol because you know you'll feel terrible.
Acamprosate doesn't cause any reaction if you drink. Its goal is to reduce the internal drive to drink rather than punishing drinking behavior. For many patients, this makes Acamprosate easier to take consistently.
Gabapentin and Topiramate are anticonvulsants used off-label for alcohol use disorder. They also affect GABA and glutamate systems, but through different mechanisms and receptor targets. They're not FDA-approved for AUD, but some providers prescribe them when first-line options aren't suitable.
The key advantage of Acamprosate is that it was specifically designed and approved for alcohol abstinence maintenance, with a well-studied safety profile over long-term use.
Acamprosate works by fixing a problem you can't see — the chemical imbalance in your brain left behind by chronic alcohol use. It won't make you feel high, won't block alcohol's effects, and won't make you sick if you drink. What it does is make sobriety feel more manageable by quieting the neurological noise that drives cravings.
If you've been prescribed Acamprosate and need help finding it at a pharmacy, Medfinder can show you where it's in stock near you. For more information about side effects or drug interactions, check out our other guides.
You focus on staying healthy. We'll handle the rest.
Try Medfinder Concierge FreeMedfinder's mission is to ensure every patient gets access to the medications they need. We believe this begins with trustworthy information. Our core values guide everything we do, including the standards that shape the accuracy, transparency, and quality of our content. We’re committed to delivering information that’s evidence-based, regularly updated, and easy to understand. For more details on our editorial process, see here.
%2C%20Color%3DOriginal.png)
