Akamprosat Viatris: Uses, Dosage & Side Effects
Acamprosate calcium 333 mg enteric-coated tablets for maintaining abstinence in alcohol-dependent patients as part of a comprehensive treatment program
Akamprosat Viatris (acamprosate calcium) is a prescription medication used to help maintain abstinence from alcohol in people who have been diagnosed with alcohol dependence (alcohol use disorder). It works by restoring the natural balance between excitatory and inhibitory neurotransmitter systems in the brain that have been disrupted by chronic alcohol use. Acamprosate is not a cure for alcoholism and does not treat alcohol withdrawal symptoms. It is most effective when used as part of a comprehensive treatment program that includes counseling, behavioral therapy, and ongoing psychosocial support. The medication is available as 333 mg enteric-coated tablets and is typically taken three times daily.
Quick Facts: Akamprosat Viatris
Key Takeaways
- Akamprosat Viatris (acamprosate calcium 333 mg) helps maintain abstinence from alcohol by restoring the balance between excitatory glutamate and inhibitory GABA neurotransmission disrupted by chronic alcohol use.
- Treatment should be started as soon as possible after alcohol withdrawal is complete and continued even if a relapse to drinking occurs; the recommended treatment duration is typically 12 months.
- The standard adult dose is two tablets (666 mg) taken three times daily with meals; patients weighing less than 60 kg may be prescribed a reduced dose of four tablets daily.
- Acamprosate is contraindicated in patients with severe renal impairment (creatinine clearance below 30 mL/min) and should be used with caution in moderate renal impairment; dose adjustment is required.
- The most common side effect is diarrhea; acamprosate does not cause sedation, does not interact with alcohol to produce unpleasant reactions, and has no known potential for dependence or abuse.
What Is Akamprosat Viatris and What Is It Used For?
Akamprosat Viatris contains the active substance acamprosate calcium, a synthetic compound that is structurally related to the naturally occurring amino acid taurine and the neurotransmitter gamma-aminobutyric acid (GABA). Acamprosate was first approved in Europe in 1989 and has since become one of the most widely prescribed medications for alcohol dependence worldwide. It is marketed under various brand names, including Campral, and the Viatris formulation provides a generic alternative that contains the same active ingredient in an enteric-coated tablet form.
Alcohol use disorder (AUD) is a chronic relapsing condition that affects an estimated 283 million people globally, according to the World Health Organization. Chronic alcohol consumption profoundly alters brain chemistry, particularly the balance between excitatory glutamatergic neurotransmission and inhibitory GABAergic neurotransmission. Over time, the brain adapts to the constant presence of alcohol by upregulating excitatory pathways (primarily through increased NMDA receptor expression and glutamate release) and downregulating inhibitory pathways. When alcohol is abruptly removed, this imbalance leads to a state of neuronal hyperexcitability that manifests as withdrawal symptoms, anxiety, insomnia, restlessness, and intense cravings for alcohol.
Acamprosate is believed to counteract this neuronal hyperexcitability by modulating glutamatergic neurotransmission. Specifically, research suggests that acamprosate interacts with the NMDA subtype of glutamate receptors and may also influence metabotropic glutamate receptors (particularly mGluR5) and voltage-gated calcium channels. By dampening excessive glutamate signaling, acamprosate helps restore a more normal neurochemical environment in the brain, which in turn reduces the protracted withdrawal symptoms and cravings that drive many patients to relapse during early recovery.
It is important to understand that acamprosate is not a treatment for acute alcohol withdrawal. It does not reduce the symptoms of withdrawal itself, such as tremor, seizures, or delirium tremens, and it should not be started until the patient has been safely detoxified. Furthermore, acamprosate does not produce any aversive reaction if a patient drinks alcohol while taking it (unlike disulfiram, which causes unpleasant symptoms when combined with alcohol). Instead, acamprosate works gradually over days to weeks to reduce the underlying neurological drive to drink, making it easier for patients to maintain their commitment to sobriety.
Clinical evidence supporting acamprosate comes from numerous randomized controlled trials conducted across Europe and the United States. A landmark Cochrane systematic review analyzing 24 randomized controlled trials involving over 6,900 patients found that acamprosate significantly reduced the risk of returning to any drinking compared with placebo, with a relative risk of 0.86 (95% CI: 0.81-0.91). The number needed to treat (NNT) was approximately 9, meaning that for every 9 patients treated with acamprosate, one additional patient maintained complete abstinence who would otherwise have relapsed. The effect was most pronounced when acamprosate was combined with psychosocial interventions such as cognitive-behavioral therapy, motivational interviewing, or 12-step facilitation programs.
Acamprosate is most effective when used as part of a comprehensive treatment approach that includes professional counseling, behavioral therapy, support groups, and ongoing medical monitoring. Medication alone is generally less effective than medication combined with psychosocial support. Your treatment plan should be individualized by your healthcare provider based on your specific needs and circumstances.
What Should You Know Before Taking Akamprosat Viatris?
Contraindications
There are several situations in which Akamprosat Viatris should not be used. The most important absolute contraindication is severe renal impairment, defined as a creatinine clearance of less than 30 mL/min. Since acamprosate is excreted entirely through the kidneys without any hepatic metabolism, patients with significantly reduced kidney function cannot adequately clear the drug, leading to dangerous accumulation. Your doctor should check your kidney function before starting treatment and periodically during therapy.
Akamprosat Viatris is also contraindicated in patients with a known hypersensitivity to acamprosate calcium or to any of the excipients in the formulation. Allergic reactions to acamprosate are rare but can include skin rashes, urticaria (hives), and in very rare cases, more serious hypersensitivity reactions. If you experience swelling of the face, lips, tongue, or throat, or develop difficulty breathing after taking the medication, seek medical attention immediately.
Breastfeeding mothers should not take acamprosate, as it is not known whether the drug passes into breast milk. Given the potential risks to the nursing infant and the lack of safety data, an alternative approach to managing alcohol dependence should be discussed with a healthcare provider.
Warnings and Precautions
Patients with moderate renal impairment (creatinine clearance between 30 and 50 mL/min) require dose adjustment and careful monitoring. Your healthcare provider may prescribe a reduced dose and monitor your kidney function more frequently to ensure the medication is being cleared adequately.
Depression and suicidal ideation are common in patients with alcohol use disorder, both during active drinking and during recovery. While acamprosate itself has not been shown to increase the risk of depression or suicidal thoughts, it is important that patients and their caregivers remain vigilant for any changes in mood, behavior, or emotional state during treatment. Any new or worsening depression, anxiety, agitation, or thoughts of self-harm should be reported to a healthcare provider promptly.
Patients with significant liver disease should be evaluated carefully before starting acamprosate. Although the drug is not metabolized by the liver and does not require hepatic dose adjustment, many patients with alcohol dependence have some degree of liver damage. Your doctor may want to assess your overall liver health as part of a comprehensive treatment evaluation.
Acamprosate should be initiated only after the patient has completed alcohol detoxification and is no longer experiencing active withdrawal symptoms. Starting the medication during acute withdrawal is not recommended, as acamprosate does not treat withdrawal symptoms and its efficacy has not been established in this setting. Treatment should be started as soon as possible after withdrawal is complete, ideally on the same day the patient achieves abstinence.
Pregnancy and Breastfeeding
The safety of acamprosate during pregnancy has not been established in adequate human studies. Animal studies have shown some evidence of teratogenicity at very high doses, though the relevance to human pregnancy at therapeutic doses is uncertain. Acamprosate should therefore be used during pregnancy only if the potential benefit to the mother clearly outweighs the potential risk to the fetus. Women of childbearing potential should be advised to use effective contraception during treatment.
As noted above, acamprosate is contraindicated during breastfeeding due to insufficient safety data. If a breastfeeding woman requires pharmacological support for alcohol abstinence, alternative medications should be considered in consultation with a specialist in addiction medicine.
Because acamprosate is eliminated entirely by the kidneys, your doctor must check your kidney function (creatinine clearance) before prescribing this medication. Do not take Akamprosat Viatris if your creatinine clearance is below 30 mL/min. Report any changes in urination, unusual swelling, or signs of fluid retention to your healthcare provider immediately.
How Does Akamprosat Viatris Interact with Other Drugs?
One of the notable advantages of acamprosate compared with many other medications is its favorable drug interaction profile. Because acamprosate is not metabolized by the liver and does not bind significantly to plasma proteins, it has minimal potential for pharmacokinetic drug interactions. It does not inhibit or induce the cytochrome P450 (CYP) enzyme system, which is responsible for metabolizing the majority of medications. This means that acamprosate can generally be safely combined with other prescription and over-the-counter drugs without concern for altered drug levels or unexpected toxicity.
The co-administration of acamprosate with naltrexone, another medication approved for alcohol dependence, has been studied in clinical trials. The COMBINE study, a large multi-center randomized controlled trial conducted in the United States, found that the combination of acamprosate and naltrexone was safe and well-tolerated. Naltrexone may increase the plasma concentrations of acamprosate by approximately 25%, but this is not considered clinically significant and does not require dose adjustment. Some clinicians use both medications together in patients who have not responded adequately to either drug alone.
Acamprosate can also be safely combined with disulfiram (Antabuse), the third medication approved for alcohol dependence. Studies have shown that the concurrent use of disulfiram and acamprosate does not produce any clinically significant pharmacokinetic interaction. This combination may be considered for patients who benefit from both the aversive effect of disulfiram and the anti-craving effect of acamprosate.
Food affects the absorption of acamprosate. When taken with food, the bioavailability of acamprosate is reduced compared with the fasted state. However, because clinical trials demonstrating the efficacy of acamprosate were conducted with the drug taken at mealtimes, the current recommendation is to take acamprosate with meals for consistency and to minimize gastrointestinal side effects.
Potential Interactions to Be Aware Of
While acamprosate has very few significant drug interactions, there are some theoretical considerations. Medications that affect renal function or renal excretion may alter acamprosate clearance. Nephrotoxic drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) used chronically, and certain antibiotics may warrant closer monitoring of kidney function when used alongside acamprosate. Patients taking any of the following should inform their prescriber:
| Drug / Class | Interaction Type | Clinical Significance | Recommendation |
|---|---|---|---|
| Naltrexone | Increases acamprosate levels ~25% | Low | Safe to combine; no dose adjustment needed |
| Disulfiram | No pharmacokinetic interaction | None | Safe to combine |
| Tetracyclines | Theoretical: reduced absorption (divalent cations) | Low | Separate doses by 2 hours if possible |
| Fluoroquinolones | Theoretical: reduced absorption (divalent cations) | Low | Separate doses by 2 hours if possible |
| NSAIDs (chronic use) | May reduce renal function | Moderate | Monitor kidney function regularly |
| Diuretics | May affect renal excretion | Low | Monitor kidney function; ensure adequate hydration |
| Alcohol | No disulfiram-like reaction | None (pharmacological) | Continue acamprosate even if relapse occurs |
It is always advisable to inform your healthcare provider about all medications you are taking, including herbal supplements, vitamins, and over-the-counter products. Although acamprosate has a very low interaction potential, a comprehensive medication review ensures the safest possible treatment plan for your individual situation.
What Is the Correct Dosage of Akamprosat Viatris?
The dosage of acamprosate is based primarily on the patient's body weight and kidney function. The enteric coating on Akamprosat Viatris tablets protects the active ingredient from stomach acid and ensures that it is released in the small intestine for optimal absorption. It is essential that the tablets are swallowed whole with a glass of water and not broken, crushed, or chewed, as this would destroy the enteric coating and potentially reduce the drug's effectiveness while increasing gastrointestinal irritation.
Adults
Standard Adult Dose (body weight 60 kg or more)
Two tablets (666 mg) taken three times daily: morning, midday, and evening, preferably with meals. Total daily dose: 1,998 mg (6 tablets).
Reduced Adult Dose (body weight less than 60 kg)
Some prescribers recommend a reduced regimen: two tablets (666 mg) in the morning and one tablet (333 mg) at midday and one tablet (333 mg) in the evening. Total daily dose: 1,332 mg (4 tablets).
| Patient Group | Daily Dose | Schedule | Notes |
|---|---|---|---|
| Adults (≥ 60 kg) | 1,998 mg (6 tablets) | 2 tablets three times daily | Take with meals |
| Adults (< 60 kg) | 1,332 mg (4 tablets) | 2 morning, 1 midday, 1 evening | Take with meals |
| Moderate renal impairment | Reduced (per physician) | Individualized | CrCl 30-50 mL/min; monitor closely |
| Severe renal impairment | Contraindicated | N/A | CrCl < 30 mL/min; do not use |
| Hepatic impairment | No adjustment needed | Standard dosing | Not metabolized by the liver |
Children and Adolescents
Acamprosate is not approved for use in children or adolescents under 18 years of age. The safety and efficacy of acamprosate in the pediatric population have not been established. Alcohol use disorder in adolescents requires specialized treatment approaches, and management should always involve a healthcare professional experienced in adolescent addiction medicine.
Elderly Patients
No specific dose adjustment is recommended for elderly patients based on age alone. However, because kidney function naturally declines with age, elderly patients are more likely to have reduced creatinine clearance. Before prescribing acamprosate to an older adult, the prescriber should assess renal function and adjust the dose accordingly if moderate renal impairment is present. Regular monitoring of kidney function is advisable throughout treatment in elderly patients.
Missed Dose
If you miss a dose of Akamprosat Viatris, take it as soon as you remember, provided it is not almost time for your next scheduled dose. If it is close to the time of your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. Missing an occasional dose is unlikely to significantly affect the medication's overall efficacy, but consistent dosing is important for optimal results. If you frequently forget doses, consider using a pill organizer or setting reminders to help maintain adherence.
Overdose
In cases of acamprosate overdose, the most commonly reported symptom is diarrhea. In more severe cases, hypercalcemia (elevated blood calcium levels) may occur due to the calcium component of the formulation. There is no specific antidote for acamprosate overdose. Treatment is supportive and symptomatic. In the event of a suspected overdose, contact a poison control center or emergency medical services immediately. Hemodialysis may be considered in severe cases, particularly in patients with renal impairment, as acamprosate is a small molecule that is dialyzable.
The recommended treatment duration is typically 12 months. Clinical studies have demonstrated that the benefits of acamprosate are greatest during the first year of treatment, with some evidence suggesting that longer treatment periods may provide additional benefit for certain patients. Treatment should be continued even if a relapse to drinking occurs, as the medication may still help reduce overall drinking days and facilitate return to abstinence.
What Are the Side Effects of Akamprosat Viatris?
Like all medications, Akamprosat Viatris can cause side effects, although not everyone will experience them. The majority of side effects reported with acamprosate are mild to moderate in severity and gastrointestinal in nature. In clinical trials, the overall rate of adverse events was similar between acamprosate and placebo groups, suggesting that the drug is generally well-tolerated. This is an important consideration, as patient adherence to medication is critical for the success of alcohol dependence treatment, and side effects are a common reason for treatment discontinuation.
One of the notable safety advantages of acamprosate is that it does not produce sedation, does not impair cognitive or psychomotor function, and has no known potential for abuse or dependence. Unlike benzodiazepines (sometimes used in alcohol withdrawal) or naltrexone (which can cause liver toxicity at high doses), acamprosate has a very favorable safety profile. Furthermore, abrupt discontinuation of acamprosate does not produce withdrawal symptoms, so the medication can be stopped at any time without tapering.
It can be challenging to distinguish side effects of acamprosate from symptoms related to alcohol withdrawal or early abstinence. Many of the gastrointestinal and neuropsychiatric symptoms reported in clinical trials occurred at similar rates in both the acamprosate and placebo groups. Your healthcare provider can help determine whether symptoms you experience are related to the medication, the recovery process, or other factors.
Very Common
- Diarrhea (10-17% of patients)
Common
- Nausea
- Abdominal pain or discomfort
- Vomiting
- Flatulence (gas)
- Itching (pruritus)
- Skin rash (maculopapular)
- Decreased libido (in men and women)
- Impotence (erectile dysfunction)
Uncommon
- Increased libido
- Confusion
- Sleep disturbance
- Paraesthesia (tingling or numbness)
- Bullous skin reactions (blistering)
- Urticaria (hives)
Rare
- Hypersensitivity reactions
- Angioedema (swelling of face, lips, tongue, or throat)
- Severe skin reactions
The diarrhea associated with acamprosate is typically mild and self-limiting, often resolving within the first few weeks of treatment. In clinical trials, diarrhea led to treatment discontinuation in fewer than 3% of patients. If diarrhea is persistent or severe, your doctor may recommend symptomatic treatment with loperamide or may consider adjusting the acamprosate dose.
Changes in sexual function, including decreased libido and erectile dysfunction, have been reported by some patients taking acamprosate. However, it is worth noting that sexual dysfunction is extremely common among people with alcohol use disorder and during early recovery, making it difficult to determine whether these symptoms are truly caused by the medication. If you experience bothersome sexual side effects, discuss them with your healthcare provider.
Contact your doctor or seek emergency medical care immediately if you experience signs of a serious allergic reaction: swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; severe skin reaction with blistering or peeling; or any other symptoms that concern you. Also report any new or worsening depression, suicidal thoughts, or significant changes in mood or behavior.
How Should You Store Akamprosat Viatris?
Akamprosat Viatris tablets should be stored at room temperature, ideally below 25°C (77°F). The tablets should be kept in their original blister packaging until the time of use, as the enteric coating can be sensitive to moisture. Exposure to excessive heat, humidity, or direct sunlight may compromise the integrity of the enteric coating and reduce the effectiveness of the medication.
Do not store the medication in a bathroom cabinet or near a sink, as bathrooms are typically humid environments that can accelerate degradation. Keep the medication in a cool, dry place, away from direct sunlight and out of the reach and sight of children. It is particularly important to secure this medication properly, as a medicine cabinet shared by household members should prevent accidental ingestion by children or others who might confuse the tablets for another medication.
Check the expiry date on the packaging before each use. Do not take Akamprosat Viatris after the expiry date, which is printed on the carton and blister strips. The expiry date refers to the last day of that month. If the tablets appear discolored, damaged, or have an unusual smell, do not take them and consult your pharmacist.
Do not dispose of unused or expired medications by flushing them down the toilet or throwing them in household waste. Return any unused medication to your pharmacist for safe disposal in accordance with local environmental regulations. This helps protect the environment and prevents accidental exposure.
What Does Akamprosat Viatris Contain?
The active substance in Akamprosat Viatris is acamprosate calcium, present at a dose of 333 mg per tablet. Acamprosate calcium is the calcium salt of N-acetyl homotaurine, a synthetic compound with a molecular weight of approximately 400 g/mol. The calcium component accounts for a small portion of each tablet and contributes minimally to dietary calcium intake at therapeutic doses.
The tablet core typically contains the following inactive ingredients (excipients): crospovidone (a disintegrant that helps the tablet break apart in the intestine), microcrystalline cellulose (a filler and binder), colloidal anhydrous silica (a flow agent), and magnesium stearate (a lubricant used in tablet manufacturing). These excipients are pharmacologically inactive and are used solely to ensure proper tablet formation, stability, and disintegration.
The enteric coating is a critical component of the tablet design. This coating is formulated using methacrylic acid copolymers (such as Eudragit) that remain intact in the acidic environment of the stomach but dissolve in the higher pH of the small intestine. This ensures that acamprosate is released in the intestine where absorption occurs, while minimizing gastric irritation. The coating may also contain talc, triethyl citrate (a plasticizer), and titanium dioxide (a whitening agent).
The tablets are white to off-white, round, biconvex, and imprinted with identifying marks. They are supplied in blister packs containing 84, 168, or other quantities depending on the market and prescribed treatment duration. If you have allergies or sensitivities to any of the listed excipients, inform your pharmacist or doctor before starting the medication.
Frequently Asked Questions About Akamprosat Viatris
Akamprosat Viatris (acamprosate calcium 333 mg) is used to help maintain abstinence from alcohol in patients with alcohol dependence (alcohol use disorder). It works by restoring the balance of brain chemicals disrupted by chronic alcohol use, helping to reduce cravings and the discomfort associated with not drinking. It should be started after alcohol withdrawal is complete and used alongside counseling and psychosocial support.
Acamprosate modulates the glutamate (excitatory) and GABA (inhibitory) neurotransmitter systems. Chronic alcohol use disrupts the balance between these systems, and when alcohol is removed, the brain becomes hyperexcitable. Acamprosate helps restore this balance, particularly by acting on NMDA glutamate receptors and calcium channels, reducing the protracted withdrawal symptoms and cravings that can trigger relapse.
While acamprosate does not produce a disulfiram-like reaction if you drink alcohol, it is not effective in actively drinking patients. The medication is designed to support abstinence after detoxification. If a relapse occurs, you should continue taking acamprosate and discuss the situation with your healthcare provider rather than stopping the medication.
The most common side effect is diarrhea, occurring in about 10-17% of patients. Other common side effects include nausea, abdominal pain, flatulence, itching, and skin rashes. Most side effects are mild to moderate and often improve over time. Importantly, acamprosate does not cause sedation, dependence, or significant interactions with alcohol.
The recommended treatment duration is typically 12 months. Treatment should be initiated as soon as possible after withdrawal is complete. If a relapse occurs during treatment, the medication should be continued rather than stopped. Some patients may benefit from longer treatment periods, depending on individual response and clinical assessment by their healthcare provider.
Yes, acamprosate and naltrexone can be used together safely. The COMBINE study examined this combination and found both medications to be well-tolerated when used concurrently. Naltrexone may slightly increase acamprosate blood levels, but this is not clinically significant. Some clinicians combine both medications for patients who have not responded to monotherapy, as the drugs work through different mechanisms.
References
All information in this article is based on internationally recognized medical guidelines, peer-reviewed clinical studies, and official prescribing information. The following sources were consulted:
- European Medicines Agency (EMA). Acamprosate calcium – Summary of Product Characteristics (SmPC). Updated 2024. Available from: www.ema.europa.eu
- U.S. Food and Drug Administration (FDA). Campral (acamprosate calcium) – Prescribing Information. Updated 2024. Available from: www.accessdata.fda.gov
- Rösner S, Hackl-Herrwerth A, Leucht S, et al. “Acamprosate for alcohol dependence.” Cochrane Database of Systematic Reviews. 2010;(9):CD004332. doi:10.1002/14651858.CD004332.pub2
- Anton RF, O’Malley SS, Ciraulo DA, et al. “Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study: a randomized controlled trial.” JAMA. 2006;295(17):2003-2017. doi:10.1001/jama.295.17.2003
- National Institute for Health and Care Excellence (NICE). Alcohol-use disorders: diagnosis, assessment and management of harmful drinking and alcohol dependence. Clinical guideline [CG115]. Updated 2024. Available from: www.nice.org.uk/guidance/cg115
- World Health Organization (WHO). Global Status Report on Alcohol and Health 2024. Available from: www.who.int
- Lingford-Hughes AR, Welch S, Peters L, et al. “BAP updated guidelines: evidence-based guidelines for the pharmacological management of substance abuse, harmful use, addiction and comorbidity.” Journal of Psychopharmacology. 2012;26(7):899-952. Updated 2023.
- Mann K, Lemenager T, Hoffmann S, et al. “Results of a double-blind, placebo-controlled pharmacotherapy trial in alcoholism conducted in Germany and comparison with the US COMBINE study.” Addiction Biology. 2013;18(6):937-946. doi:10.1111/adb.12012
- British National Formulary (BNF). Acamprosate calcium. National Institute for Health and Care Excellence. Updated 2025. Available from: bnf.nice.org.uk
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