Acamprosate (Campral)

What it treats

Acamprosate is approved by the U.S. Food and Drug Administration for the maintenance of abstinence from alcohol in adults with alcohol use disorder who are already abstinent at the start of treatment. It's a first-line option alongside naltrexone in most guidelines.

It's meant for the phase after someone has stopped drinking. It doesn't treat acute withdrawal and it doesn't reduce heavy drinking days if drinking continues at a heavy level. Its job is to make the weeks and months after quitting easier to hold on to.

How it works

When someone drinks heavily over time, the brain's glutamate system ramps up to counter the sedating effects of alcohol. When alcohol goes away, that ramped-up glutamate activity stays elevated for weeks, and it drives the restless, irritable, sleep-disrupted feeling that a lot of people describe in early abstinence. That state is one of the reasons early recovery is hard to hold.

Acamprosate is thought to quiet that glutamate overshoot and support the balance between glutamate and GABA. The result, over weeks, is a calmer background and less pull back to drinking.

Receptor mechanism (detail)

Acamprosate's exact mechanism isn't fully worked out. Current understanding points to modulation of NMDA glutamate receptors and effects on GABA-A and possibly metabotropic glutamate receptors, dampening the glutamate hyperactivity of protracted abstinence. It has essentially no effect on the reward pathway directly and doesn't produce any subjective drug effect.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

The standard dose is 666 mg (two 333 mg tablets) three times a day, taken with or without food. The three-times-a-day schedule is the main practical challenge. Some clinicians accept a slightly lower total if the third dose is what gets missed, though the trial evidence is for the full 1998 mg per day.

Renal dose adjustment matters. In moderate impairment (creatinine clearance 30 to 50 mL/min), the dose is cut in half. In severe impairment (below 30 mL/min), acamprosate isn't used.

Acamprosate is started after alcohol has been stopped. It doesn't need to wait for a long dry period, and it isn't a treatment for acute withdrawal.

Safety monitoring

• Renal function. A baseline creatinine and periodic checks. The kidneys clear this drug.
• Diarrhea. Common early. Ask about it. Persistent diarrhea that limits eating or fluid intake means the dose or the schedule needs a look.
• Mood. Some people report low mood; suicidality has been reported and warrants a routine check.
• Adherence. The three-times-a-day schedule is the main reason acamprosate stops working in the real world.

Because acamprosate isn't hepatically metabolized, LFT monitoring isn't required in the same way it is for naltrexone or disulfiram. That's a genuine advantage in people with liver disease from alcohol.

What to expect

Common side effects

• Diarrhea (the standout).
• Nausea.
• Abdominal discomfort or flatulence.
• Headache.
• Trouble sleeping.
• Fatigue.
• Itching or rash.

Diarrhea is the most common reason people stop. Taking doses with meals sometimes helps.

Serious side effects and warnings

Serious problems are uncommon.

• Suicidality. Reported in clinical trials at low but real rates. Any new or worsening low mood or suicidal thinking needs prompt attention.
• Kidney disease. Not a side effect but a contraindication in severe renal impairment. In moderate impairment, the dose is halved.
• Serious allergic reactions. Rare.

Sexual and relational effects

Sexual side effects aren't a common complaint with acamprosate. The relational conversation is the same as with any medication for alcohol use disorder: partners, family, sponsors, and recovery communities carry most of the weight. Medication is a support. If sexual function shifts after starting, that's worth raising with the prescriber, because early abstinence itself changes libido and function for a lot of people.

Weight, appetite, and sleep

Weight change on acamprosate is usually modest. Diarrhea can affect appetite and hydration early. Sleep can be disrupted in the first weeks and usually settles.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual.

Acamprosate is typically started once alcohol has been stopped. It doesn't treat acute withdrawal, so benzodiazepines or other withdrawal-specific care come first if needed. The tablets are enteric-coated and should be swallowed whole, not crushed. Taking a dose with each meal is the standard way to remember the three-times-a-day schedule.

A baseline creatinine is standard. The dose is halved in moderate renal impairment.

Missed doses and interactions

If a dose is missed, take it when remembered unless the next dose is close. Don't double up.

Acamprosate has almost no meaningful drug interactions, which is one of its advantages. It's not hepatically metabolized, so the CYP450 interactions that complicate other medications don't apply. It can be combined with naltrexone; some clinicians use both when neither alone is enough, though the added benefit isn't dramatic.

Alcohol on top of acamprosate isn't dangerous the way it is with disulfiram. There's no reaction. But the goal is abstinence, and drinking on the medication is a signal that the plan needs a look.

Stopping and tapering

Acamprosate doesn't cause physical dependence and there's no medical withdrawal from stopping. It can be stopped without a taper. The bigger question is whether the timing is right: many people who stop early relapse, and restarting after a slip is fine.

Pregnancy and breastfeeding

Data on acamprosate in pregnancy is limited. It does cross the placenta. Guidelines don't recommend routine use in pregnancy. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with a prescriber, weighing the risks of continued drinking against those of the medication.

Cost and generic availability

Acamprosate has been generic for many years and is inexpensive. The brand name Campral is no longer widely used. Insurance coverage is generally straightforward.

Common questions

How long does it take to work? The subtle easing of the restless, edgy feeling of early abstinence often shows up in the first couple of weeks. The bigger benefit (holding abstinence over months) builds gradually. Guidelines support at least 3 to 12 months of treatment.

Can I drink on this? Physically, there's no reaction if someone drinks. But the medication is designed to hold abstinence, so drinking on it usually means the treatment plan needs a look.

Is it addictive? No. Acamprosate isn't psychoactive and isn't controlled.

Do I have to take it three times a day? Yes. The trials that showed benefit used three-times-daily dosing, and skipping the third dose often is the most common reason it stops working.

Can I take this with naltrexone? Yes, and some clinicians do. The combination is well tolerated. The added benefit over either alone is modest but real for some people.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• How long should I plan to stay on it?
• What do I do if I have a slip?
• Is my kidney function fine for the full dose?
• What signs would tell you it isn't the right medication for me?

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes, and current as of June 8, 2026.

• U.S. Food and Drug Administration. Acamprosate calcium (Campral) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Acamprosate.
• DailyMed, U.S. National Library of Medicine. Acamprosate calcium.
• American Society of Addiction Medicine. Clinical Practice Guideline on Alcohol Use Disorder.
• National Institute on Alcohol Abuse and Alcoholism. Treatment for alcohol problems.