What You Should Know About Acamprosate Side Effects

Acamprosate (formerly sold under the brand name Campral) is an FDA-approved medication that helps people maintain sobriety after quitting alcohol. Like all medications, it can cause side effects — but most are mild, and serious reactions are rare.

Understanding what to expect can help you stick with your treatment and know when something needs medical attention. This guide covers the most common side effects, the serious ones to watch for, and practical tips for managing them.

What Is Acamprosate?

Acamprosate is a GABA analogue that helps restore the chemical balance in your brain after chronic alcohol use. It's taken as two 333 mg delayed-release tablets, three times a day, for a total daily dose of 1,998 mg. You can learn more about how it works in our mechanism of action guide.

Acamprosate is not a controlled substance and does not cause dependence. It works best when combined with counseling and support programs.

Common Side Effects

The following side effects were reported in clinical trials and are listed in the FDA prescribing information. Most are mild to moderate and tend to improve over the first few weeks of treatment.

• Diarrhea — This is the most frequently reported side effect, affecting up to 17% of patients in clinical trials. It is usually mild and often resolves on its own.
• Nausea — Stomach upset is common when starting Acamprosate, especially if taken on an empty stomach.
• Flatulence (gas) — Gastrointestinal side effects are the most common category overall.
• Insomnia — Some patients report difficulty falling or staying asleep.
• Anxiety — Feelings of nervousness or restlessness may occur, though this can also be related to early sobriety itself.
• Depression — Mood changes should be monitored closely (more on this below).
• Dizziness — Usually mild and more noticeable when standing up quickly.
• Dry mouth — Staying hydrated can help manage this.
• Sweating — Increased perspiration has been reported in some patients.
• Itching (pruritus) — Mild skin itching without a rash is occasionally reported.
• Weakness (asthenia) — General fatigue or feeling weak, particularly in the first weeks.
• Loss of appetite (anorexia) — Some patients experience reduced hunger.

Serious Side Effects

Serious side effects from Acamprosate are uncommon, but they do require immediate medical attention.

Suicidal Thoughts or Behavior

The FDA label includes a warning about suicidality. People with alcohol dependence are already at higher risk for depression and suicidal thinking. In clinical trials, suicidal ideation, suicide attempts, and completed suicides were reported in Acamprosate-treated patients, though the rate was not significantly different from placebo.

What to do: If you or someone close to you notices new or worsening depression, unusual mood changes, or any thoughts of self-harm, contact your doctor immediately or call the 988 Suicide and Crisis Lifeline.

Acute Kidney Failure

Rare postmarketing reports of acute kidney failure have been associated with Acamprosate. This medication is eliminated entirely through the kidneys, which is why kidney function testing is done before starting treatment.

What to do: Tell your doctor if you notice significantly decreased urination, swelling in your legs or feet, or unexplained fatigue.

Severe Allergic Reactions

Though rare, allergic reactions including skin rash, hives, swelling of the face or throat, and difficulty breathing have been reported.

What to do: Seek emergency medical help immediately if you experience swelling of your face, lips, tongue, or throat, or have trouble breathing after taking Acamprosate.

Irregular Heartbeat

Cardiac arrhythmias have been reported in rare cases during postmarketing surveillance.

What to do: Contact your doctor if you feel your heart racing, pounding, or beating irregularly.

Side Effects in Specific Populations

People with Kidney Problems

Acamprosate is contraindicated in patients with severe kidney impairment (creatinine clearance ≤30 mL/min). For moderate kidney impairment (CrCl 30–50 mL/min), the dose should be reduced to 333 mg three times daily. Your doctor will check your kidney function before prescribing. Learn more in our dosage and uses guide.

Older Adults

Elderly patients may be more susceptible to side effects due to age-related decline in kidney function. Kidney function should be monitored more frequently in this group.

Pregnant or Breastfeeding Women

Acamprosate is classified as Pregnancy Category C — meaning animal studies have shown potential risk, but there aren't enough human studies. It should only be used during pregnancy if the potential benefit clearly outweighs the risk. It's not known whether Acamprosate passes into breast milk.

How to Manage Side Effects

Most Acamprosate side effects are manageable with simple adjustments:

• For diarrhea: Take Acamprosate with meals. Stay hydrated. If diarrhea persists beyond two weeks, talk to your doctor. Over-the-counter anti-diarrheal medication like Loperamide (Imodium) may help.
• For nausea: Taking the medication with food can reduce stomach upset. Eating smaller, more frequent meals may also help.
• For insomnia: Take your last dose earlier in the evening. Practice good sleep hygiene — avoid screens before bed, keep a consistent schedule, and limit caffeine.
• For dizziness: Stand up slowly from sitting or lying positions. Avoid driving until you know how Acamprosate affects you.
• For dry mouth: Drink water frequently. Sugar-free gum or lozenges can stimulate saliva production.
• For anxiety or depression: Talk to your prescriber. These symptoms may be related to early sobriety rather than the medication itself, but either way, your doctor should know.

Important: Do not stop taking Acamprosate without talking to your doctor, even if you experience side effects. Abruptly stopping is not dangerous (it doesn't cause withdrawal), but your doctor may want to adjust the dose or try a different approach rather than discontinuing treatment.

When to Call Your Doctor

Call your doctor or seek medical attention if you experience any of the following:

• New or worsening depression or thoughts of self-harm
• Signs of an allergic reaction (rash, hives, swelling, difficulty breathing)
• Decreased urination or swelling in your extremities
• Irregular or rapid heartbeat
• Severe or persistent diarrhea that doesn't improve
• Any side effect that feels concerning or interferes with daily life

Final Thoughts

Acamprosate is generally well tolerated, and most side effects are mild gastrointestinal symptoms that improve with time. The most important thing is to stay in communication with your prescriber — they can help you manage side effects so you can stay on track with your recovery.

If you're having trouble finding Acamprosate at your pharmacy due to the current supply shortage, use Medfinder to check real-time stock at pharmacies near you.