Acamprosate and naltrexone are the two first-line medications used in MAT for alcohol use disorder (AUD), and while both are FDA-approved and effective, choosing between them isn’t simple. They work through different biological pathways, suit different treatment goals, and carry different medical considerations to weigh.
We know that deciding to address alcohol use is one of the hardest steps a person ever takes, and the question of which medication makes sense for you deserves a clear answer. This guide compares acamprosate and naltrexone in plain language so you can talk through the choice with a clinician and start care that fits your life.
Acamprosate and naltrexone are both FDA-approved medications for alcohol use disorder, but they work differently and tend to suit different goals. The table below summarizes the practical differences most people care about when choosing between them, and the rest of this guide walks through each row in more detail.
| Feature | Acamprosate (Campral) | Oral Naltrexone (ReVia) | Injectable Naltrexone (Vivitrol) |
| Primary goal | Maintain abstinence after you’ve stopped drinking | Reduce heavy drinking days and cravings | Reduce heavy drinking days and cravings |
| Form | Oral tablet | Oral tablet | Monthly intramuscular injection |
| Typical dose | 666 mg three times a day | 50 mg once a day | 380 mg every 4 weeks |
| Start with active drinking? | No, usually started after detox | Yes, often okay | No, must be opioid-free first |
| Main organ to monitor | Kidneys | Liver | Liver |
| Cannot be used if you… | Have severe kidney disease | Are taking opioids or have acute liver failure | Are taking opioids or have acute liver failure |
| Common side effects | Diarrhea, gas, anxiety | Nausea, headache | Injection-site reactions, nausea |
| Adherence advantage | Daily routine | Daily routine | Once-monthly injection |
If your priority is reducing heavy drinking and cravings, naltrexone is usually the first conversation. If your priority is staying alcohol-free after a period of sobriety, acamprosate is usually the first conversation. Real life is rarely that clean, which is why a 15-minute medical visit is the best way to land on the right answer.
Acamprosate and naltrexone treat the same condition through completely different biological routes. Understanding the difference helps explain why the same person might respond well to one and not the other.
Acamprosate is thought to work by calming the overactive glutamate signaling that lingers after heavy drinking ends. That post-withdrawal restlessness, anxiety, and trouble sleeping is a major driver of relapse, and acamprosate is designed to reduce it. This is why it tends to work best after you’ve stopped drinking and the body is adjusting.
Naltrexone blocks opioid receptors in the brain, which dulls the rewarding “buzz” alcohol normally produces. With less reward to chase, cravings tend to soften and heavy drinking days tend to drop.
Our naltrexone therapy program covers both the daily oral form and the monthly injection. The same medication is also used for opioid use disorder, which is why it can’t be combined with opioid pain medications or active opioid use.
Some people take naltrexone in a non-daily pattern called the Sinclair Method, dosing before planned drinking to gradually reduce the urge over weeks.
The mechanism difference is the reason the two medications have different “best uses.” Acamprosate doesn’t reduce cravings the way naltrexone does, and naltrexone doesn’t directly settle post-withdrawal symptoms the way acamprosate does. This is also why some clinicians consider using both at the same time in certain situations.
The largest synthesis we have is a 2023 systematic review and meta-analysis published in JAMA that pooled 118 trials and roughly 21,000 participants. Both medications outperformed placebo, but with the pattern that has held up across decades of research.
Acamprosate has the larger effect on maintaining continuous abstinence, meaning that once you’ve stopped drinking, it helps you stay stopped. This is the medication of choice if your goal is to remain alcohol-free and you’ve already detoxed or had a few weeks of sobriety.
Naltrexone has the larger effect on reducing heavy drinking days and cutting cravings. The number-needed-to-treat (NNT), or how many people need to be treated for one to benefit, is generally in the low teens for both medications, which is considered solidly effective in primary care medicine.
Both medications are considered first-line options for alcohol addiction treatment, which means there’s no automatic winner. The right choice depends on:
A 30-minute conversation with a prescriber covers all of that and lands on a real answer.
Knowing what the daily reality of each medication looks like often makes the choice clearer. Here’s a side-by-side of what to plan for once you start.
| What to Expect | Acamprosate | Oral Naltrexone | Injectable Naltrexone |
| Daily routine | Three pills, three times a day, with or without food | One pill once a day | No daily pill, clinic visit every 4 weeks |
| Time to start working | 5 to 8 days for steady levels | First dose has effect; full benefit over weeks | Effect begins within days of injection |
| Required labs before starting | Kidney function (creatinine, eGFR) | Liver function (AST, ALT) | Liver function plus opioid-free verification |
| Most common side effect | Diarrhea or stomach upset | Nausea (often eases after the first week) | Injection-site soreness |
| When to call your provider | Severe diarrhea, mood changes | Yellowing of the skin or eyes, severe nausea, dark urine | Same as oral, plus signs of injection-site infection |
| Pregnancy considerations | Discuss individually with prescriber | Discuss individually with prescriber | Discuss individually with prescriber |
| Typical length of treatment | At least 3 to 6 months, often longer | At least 3 to 6 months, often longer | At least 3 to 6 months, often longer |
A few points are worth focusing on. Naltrexone in any form requires you to be opioid-free before starting, usually 7 to 14 days clear of any opioids, including prescription pain medication.
Starting it too soon can trigger a hard, sudden opioid withdrawal that’s both unpleasant and avoidable. Your prescriber will ask about every medication and supplement you take before writing the script.
Acamprosate’s main constraint is kidney function. If your kidneys aren’t filtering well, the dose is reduced or the medication is avoided. A simple blood test before starting is enough to make this call.
Most prescribing decisions come down to a few practical questions. The list below is what a prescriber is mentally walking through when you sit down together.
Acamprosate is often the better fit when you:
Naltrexone is often the better fit when you:
Injectable naltrexone deserves a closer look when:
If none of these fit cleanly, that’s normal. Real cases are messier than checklists, and a 15-minute virtual visit with our team can sort out the right starting point in one appointment.
Despite acamprosate and naltrexone being effective and on the market for over 20 years, only about 1.9% of adults with alcohol use disorder in the U.S. actually received medication for it in 2023, according to a recent analysis of substance use disorder treatment facilities.
The reasons are layered, and most of them have nothing to do with whether the medications work:
Closing this gap is the reason our network looks the way it does. We deliver MAT through three formats so distance, work schedules, and small-town logistics aren’t the reason someone goes without medication:
If virtual care fits your situation, our guide to getting a naltrexone prescription online walks through how the evaluation, lab coordination, and any monthly injections work end-to-end.
We accept Medicaid, Medicare, and major commercial insurers including Anthem Blue Cross Blue Shield, UnitedHealthcare, Humana, Cigna, and Kaiser Permanente. If you’ve been told a medication “isn’t covered” before, it’s worth a second look in 2026, since coverage rules have shifted in many states.
A reasonable question is: if they work through different pathways, why not just take both? Some trials have looked at this. The results are mixed, and routine combination therapy isn’t a default recommendation.
That said, combination is sometimes considered when one medication alone isn’t producing the result a person and their prescriber were hoping for, or when someone has both strong cravings and significant post-withdrawal anxiety. The decision is individualized, and it generally happens after a few months on monotherapy rather than at the very beginning.
Both medications work better when paired with some form of counseling or recovery support. The exact format varies. Some people do best with weekly individual therapy, others with group sessions or behavioral health services integrated into their medical visits.
Our care teams can build either approach into your treatment plan, and counseling is available in person, in mobile sites, and via telehealth.
If anxiety, depression, or trauma is part of the picture, dual diagnosis treatment treats both conditions at the same time rather than asking you to wait for one to be “fixed” before addressing the other.
You don’t have to figure this out alone. Whether you’re researching for yourself or someone you love, our admissions team can answer the questions that come up after reading something like this. We can talk through what your insurance covers, what the first appointment looks like, whether telehealth is an option in your area, and how soon you can start.
Call (866) 394-6123 for a confidential conversation, or find a clinic or mobile site near you and request an appointment online.
What are acamprosate and naltrexone used for?
Both are FDA-approved medications for alcohol use disorder. Acamprosate is generally prescribed to support staying alcohol-free after you’ve stopped drinking, while naltrexone is generally prescribed to reduce heavy drinking days and alcohol cravings. They can be used at different stages of treatment depending on your goals.
Which one works better?
Neither one “wins” overall. Acamprosate has a slightly larger effect on maintaining abstinence; naltrexone has a slightly larger effect on reducing heavy drinking and cravings. The right choice depends on what you’re trying to accomplish and your medical history.
Do I have to stop drinking before I start?
For acamprosate, yes. It’s typically started after you’ve stopped drinking and any acute withdrawal has passed. For oral naltrexone, no, since many people start it while still drinking.
For injectable naltrexone, you don’t need to be alcohol-free, but you do need to be opioid-free for at least 7 to 14 days.
Can I drink while taking these medications?
Drinking on naltrexone won’t make you sick (that’s disulfiram, a different medication), but you’ll likely notice the alcohol feels less rewarding. Drinking on acamprosate won’t make you sick either, but acamprosate is designed to support abstinence, so drinking works against the medication’s purpose. Talk through your specific situation with your prescriber.
Are these medications safe long-term?
Both are considered safe for the long courses most people need, typically 6 to 12 months and sometimes longer. Periodic blood tests (kidney function for acamprosate, liver function for naltrexone) confirm everything is on track.
How much do they cost?
Both are available as generics, which keeps the cost manageable for most people. Coverage varies by plan, but Medicaid covers at least one AUD medication in roughly 90% of managed care plans, and most commercial insurers cover both. Our team can verify your specific benefits before your first appointment.
What if I have liver or kidney problems?
Naltrexone is processed by the liver, so significant liver disease usually rules it out. Acamprosate is processed by the kidneys, so severe kidney disease usually rules it out. A simple lab panel before starting is enough to make the call, and most people don’t have either problem.
Can I switch from one to the other?
Yes. If one medication isn’t working or causing side effects you can’t live with, switching is straightforward. There’s typically a short washout period, but it’s not weeks-long.
What about disulfiram (Antabuse)?
Disulfiram is a third FDA-approved medication for AUD that causes a strongly unpleasant reaction if you drink while taking it. Modern guidelines generally favor acamprosate or naltrexone over disulfiram because the evidence is stronger and the safety profile is friendlier, but disulfiram is still used in specific situations.
Do I need counseling along with the medication?
Counseling isn’t legally required, but the evidence is consistent: medication plus counseling outperforms medication alone. We build counseling into our treatment plans through clinic, mobile, and telehealth visits, and we’ll work with whatever level of support fits your life.
If someone you care about may need help with alcohol, the most important next step isn’t having every answer in advance. It’s talking to someone who does this every day.
Our team can help you understand what treatment looks like, whether insurance covers it, and how to start a conversation that doesn’t end in defensiveness. Call (866) 394-6123 for a confidential, no-pressure conversation.
