Acamprosate (Campral): The Alcohol Medication That Starts After You Stop

What is Campral?

Campral is the original brand name for acamprosate calcium, a pill approved by the FDA to help people stay off alcohol after they have stopped. The brand is listed as discontinued in FDA records, so a pharmacy today fills a prescription for “Campral” with generic acamprosate delayed-release tablets. Same drug, same 333 mg tablet.

It is the quiet one of the three FDA-approved alcohol medications. Naltrexone blunts the reward from a drink. Disulfiram makes a drink punish you. Acamprosate does neither. It is built to protect a decision the person has already made.

The acamprosate column comes from the FDA label. The other two are summarized from our naltrexone, Vivitrol and Antabuse comparison.

How does acamprosate work?

Nobody knows exactly. The label says so plainly: the mechanism is “not completely understood.” The working theory is that long, heavy drinking throws the brain’s balance between excitation and inhibition off, and acamprosate, acting on the glutamate and GABA systems, helps restore it.

In practical terms, NIAAA says acamprosate is thought to ease the anxiety, restlessness, low mood, and poor sleep that can come as the brain adjusts to going without alcohol. For some people, that discomfort, more than any pull toward a drink, is what makes the early weeks hard.

It does not do much else. The label says that in animals it showed no anticonvulsant, antidepressant, or anti-anxiety effect outside its effect on alcohol dependence, no tolerance or dependence, and that people in trials had no withdrawal when it was stopped.

Campral dosage

• The usual dose is 666 mg, two 333 mg tablets, three times a day
• A lower dose may work for some people, per the label
• It can be taken with or without food; the trials gave it with meals, and the label suggests that for people who eat three meals a day
• The tablets are delayed-release and enteric-coated; swallow them whole, without splitting, chewing, or crushing them
• Steady blood levels take about 5 days

Six pills a day is the real weakness. A medication taken three times a day asks a lot of someone whose days are still shaky. With this drug, a pill organizer and doses tied to meals decide whether it gets taken at all.

Kidneys: the one limit that decides who can take it

Acamprosate is not broken down by the liver. It leaves the body unchanged through the kidneys, and the label says no dose change is needed for mild to moderate liver impairment. That is why it comes up for heavy drinkers whose livers are already damaged, although the label’s liver data cover only mild to moderate impairment, not severe liver disease. Kidney function is the gate.

• Normal kidney function: standard dose
• Moderate impairment (creatinine clearance 30 to 50 mL/min): one 333 mg tablet three times a day
• Severe impairment (creatinine clearance 30 mL/min or less): do not use

In moderate and severe kidney impairment, the label reports peak blood levels about two and four times higher than in healthy people. It also notes that older adults are more likely to have reduced kidney function, so a prescriber may check it before and during treatment. The label lists acute kidney failure among serious events reported after approval outside the U.S., in at least three patients.

What happens if you drink on Campral?

No reaction. The label says acamprosate is not known to cause alcohol aversion and does not cause a disulfiram-like reaction when someone drinks. It also says acamprosate does not change how the body handles alcohol, and alcohol does not change how the body handles acamprosate.

That does not make drinking on it a good idea. It does mean a slip does not set off a reaction the way a drink on disulfiram can, and the label’s instruction after a slip is to keep going: treatment should be maintained if the person relapses, and patients should keep taking it as directed and tell their doctor about the drinking.

One caution. If a slip turns back into daily drinking, the body can become dependent again, and stopping can bring withdrawal. The label is clear that acamprosate does not eliminate or diminish withdrawal symptoms.

Campral side effects

Diarrhea is the one that stands out. In the label’s pooled trials, 16 percent of people on acamprosate had diarrhea, against 10 percent on placebo, and it was the only side effect that led more than 1 percent of people to stop. The 2010 Cochrane review found the same: diarrhea was the only side effect reported more often than on placebo.

Other effects that showed up at least 3 percent of the time and more often than on placebo in at least one dose group included gas, nausea, weakness, loss of appetite, anxiety, insomnia, dizziness, dry mouth, itching, tingling, and sweating. Apart from diarrhea, none ran more than 3 percentage points above placebo.

Depression and suicidal thoughts

This is the warning to know. In the label’s controlled trials, suicidal events (thoughts, attempts, or completed suicide) were infrequent but more common on acamprosate: 1.4 percent versus 0.5 percent in studies of six months or less, and 2.4 percent versus 0.8 percent in year-long studies. Depression itself was reported at similar rates on acamprosate and placebo.

The label notes that many of these events happened around a return to drinking, and that no consistent link was found between how recovery was going and when suicidal thinking appeared. Its instruction is to watch for depression or suicidal thinking, and it asks families and caregivers to watch too and to tell the prescriber. If someone is in immediate danger, call 911; for thoughts of suicide, call or text 988.

Pregnancy, breastfeeding, and other drugs

The label says acamprosate caused birth defects in rats and rabbits at doses near or above the human dose, that there are no adequate studies in pregnant women, and that it should be used in pregnancy only if the benefit justifies the risk. It is not known whether it passes into human milk. Anyone pregnant, planning to be, or breastfeeding should raise it before starting.

Interactions are few. The label reports that alcohol, diazepam, and disulfiram do not change acamprosate levels, and that no clinically important interaction with naltrexone was seen, although naltrexone raised acamprosate levels modestly with no dose change recommended.

Does acamprosate work?

Modestly, and the best evidence agrees on that word.

The Cochrane review pooled 24 randomized trials with 6,915 people. Compared with placebo, acamprosate lowered the relative risk of returning to any drinking by about 14 percent; roughly one extra person stayed abstinent for every nine treated. Across the trials, people on it also had about 11 more days without drinking, on average. It did not significantly reduce heavy drinking. The authors called the effects rather moderate, but said they should be weighed against how often alcohol dependence relapses and how few treatments exist.

A 2023 JAMA meta-analysis of 118 trials landed in the same place: acamprosate and oral naltrexone were the two medications with the strongest support, and about 11 people needed to take acamprosate to keep one from returning to any drinking.

The COMBINE problem

Then there is the trial cited against it. The COMBINE study, published in JAMA in 2006, randomized 1,383 recently abstinent U.S. adults to naltrexone, acamprosate, both, or placebo, with or without an intensive counseling program. Naltrexone helped. Acamprosate showed no effect on drinking, alone or in any combination.

The studies are not answering quite the same question. The trials behind the label enrolled people after inpatient detox who were abstinent on the day they started, and measured staying abstinent. COMBINE gave acamprosate at 3 grams a day, a higher dose than the label’s, to outpatients, and measured percent of days abstinent and time to heavy drinking. The trials do not settle which difference matters. The fair reading is that acamprosate helps some people hold abstinence, and nobody should expect it to do the work of a treatment program.

Whatever the size of the effect, few people get to find out. In 2024, only 2.4 percent of U.S. adults with a past-year alcohol use disorder received medication for it, according to federal survey data reported by NIAAA.

Acamprosate vs naltrexone

Neither is simply stronger. The choice usually turns on five things.

• Goal. Acamprosate is approved for people who have stopped and want to stay stopped. Naltrexone can help someone cut down, and NIAAA notes the pill can be started while a person is still drinking.
• Liver. Acamprosate skips the liver. Naltrexone carries liver warnings.
• Kidneys. The reverse: severe kidney disease rules acamprosate out.
• Opioids. Naltrexone blocks them and needs an opioid-free start. Acamprosate does not block opioids, so being on buprenorphine or methadone, or needing opioid pain medicine, does not rule it out on that ground.
• Pill burden. Six tablets a day versus one pill or one monthly shot.

NIAAA says that if one medication does not work, trying another often helps.

Why detox comes first

Acamprosate is for the weeks after withdrawal. The label says to start it as soon as possible after alcohol withdrawal, once the person has achieved abstinence, as part of a program that includes counseling and support. The order matters. A fourth trial described on the label enrolled people who had not gone through detox and did not have to be abstinent at the start, some with other drug use, and there acamprosate did no better than placebo.

For someone who drinks daily and gets shakes, sweats, or a racing heart when they stop, withdrawal can progress to seizures or delirium tremens, and MedlinePlus describes the severe form as a medical emergency. For someone who is physically dependent, the safe order is withdrawal first, managed by a clinician, then the medication. The alcohol withdrawal timeline shows when the dangerous hours fall, the Librium, Ativan and Valium guide covers the medications used during withdrawal, and our alcohol detox guide covers where to go in New Jersey.

When you call a program, ask one specific question: will you start acamprosate or naltrexone before discharge, or hand me to a prescriber who will? A gap of weeks between discharge and the first prescription is the gap the medication is meant to cover.

In New Jersey

NIAAA notes that no special training or license is needed to prescribe the FDA-approved alcohol medications, so a primary care doctor can start acamprosate. Under New Jersey law P.L.2017, c.28, fully insured New Jersey plans and the State Health Benefits and School Employees’ plans cannot require prior authorization for the first 180 days per plan year of in-network treatment your own physician, psychologist or psychiatrist finds medically necessary, or, during those same 180 days, for outpatient prescription drugs that treat substance use disorder, such as buprenorphine and naltrexone, when that clinician finds them medically necessary. Self-funded employer plans, Medicare and Medicaid are not covered by that rule, so verify with the plan. Our insurance guides go plan by plan.

For help independent of us, the state’s IME Addictions Access Center at 1-844-276-2777 screens NJ FamilyCare and uninsured residents and refers them to treatment, and ReachNJ, the state treatment line, is at 1-844-732-2465. Periscope Behavioral Health, which publishes this site, is opening a medical detox in Hammonton, Atlantic County, expected Summer 2027. Until it opens, Periscope Behavioral Health at (888) 313-3583, our publisher’s admissions line, can talk through options in New Jersey and Florida, including facilities Periscope operates. What a plan covers depends on the plan and the facility’s network status.

Who acamprosate fits

Someone who has finished withdrawal, wants to stay stopped, and is worn down by the restless, sleepless weeks that follow. Someone whose liver rules out other options but whose kidneys are fine. Someone on buprenorphine or methadone who cannot take naltrexone. Someone willing to build a day around three doses.

It fits less well for someone who wants to cut down rather than stop, someone with severe kidney disease, or someone who will not manage six pills a day. For them, the conversation with the prescriber starts somewhere else.