How Long Does Acamprosate Stay in Your System?

The terminal half-life of a regular dose of acamprosate ranges anywhere from 20-30 hours. Acamprosate reaches steady levels within 5 days of regular dosing, while peak concentrations occur within 3-8 hours after administered dose. More on acamprosate and its metabolism here.

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Reviewed by: Dr. Dili Gonzalez, M.D.

ARTICLE OVERVIEW: The half-life of a regular dose of acamprosate ranges is around 20-30 hours, but effects are usually dependent on dose continuation.This article reviews the basics of metabolism and how to use acamprosate in addiction recovery.


Main Acamprosate Uses

Acamprosate (brand name Campral) is used to help people maintain sobriety after they stop drinking.It can help cut cravings for alcohol and address protracted symptoms of alcohol withdrawal (PAWS). How does it work?

It is known that long term and excessive drinking changes the brain’s chemistry and alters the way the brain works. Acamprosate helps the brain to start working normally again and reduces the desire for alcohol or cravings which can seriously jeopardize the recovery process. People who use acamprosate along with counseling, social support and adequate alcohol treatment have the best chances in succeeding in alcohol recovery.

In sum, acamprosate works to treat alcoholism by helping balance out the brain. When used in combination with psychotherapy, it can be an effective tool to help you remain abstinent.

How Do You Take Acamprosate?

Acamprosate treatment is generally initiated after a person has stopped drinking, but treatment can also begin during withdrawal. It has also proven to be safe for use even while still drinking (or with benzodiazepines) during a medically supervised withdrawal. However, acamprosate effectiveness and best outcomes occur when combined with psycho-social support:

  • Behavioral therapy
  • Psychotherapy
  • Social support groups

Acamprosate comes in a tablet with a delayed-release mechanism. The tablet should not be split, cut, chewed or crushed. It is intended for oral use only, usually taken with regular meals. The recommended dose of acamprosate is two 333 mg tablets (666 mg per dose) taken three times daily. Doctors recommend taking acamprosate along with breakfast, lunch and dinner to help you remember all three doses.

How it Works

Researchers don’t really know HOW acamprosate works. They hypothesize that chronic drinking alters the normal balance between the excitation and inhibition of nerve cells in the brain. They think that acamprosate helps restore this balance.

In fact, studies in animals have provided evidence to suggest acamprosate may interact with glutamate and GABA neurotransmitter systems centrally. The medicine is thought to stabilize the chemical balance in the brain that would otherwise be disrupted by alcoholism, possibly by blocking glutaminergic N-methyl-D-aspartate receptors, while gamma-aminobutyric acidtype A receptors are activated.

Peak Levels And Half-Life Of Acamprosate

Acamprosate is absorbed into the bloodstream through the paracellular route in the gastro-intestinal tract. Absorption is rapid (but limited) after oral administration. The absolute bioavailability of acamprosate after oral administration is about 11%. The plasma concentrations of acamprosate reach steady levels within 5 days of regular dosing, while peak plasma concentrations average 350 ng/mL and occur within 3-8 hours after administered dose. The terminal half-life of a regular dose of acamprosate (2 x 333mg) ranges anywhere from 20 up to 30 hours.

Acamprosate does not get metabolized in the human system and it’s not protein bound. It is excreted exclusively through the kidneys. Because of its renal excretion only, some patients should be cautious when taking it. This includes pregnant women and people with kidney problems. Also, the following warning appear on the acamprosate PubChem listing:

1. Patients with moderate renal impairment are advised to reduce dosage to one 333mg tablet a day.
2. People age of 65 or older have a higher risk of diminished renal function. Upon starting acamprosate use in geriatric populations, baseline and frequent renal function tests should be performed.
3. For children or adolescents with alcohol problems, acamprosate should be prescribed with caution. The medication’s safety and efficacy have not been fully evaluated in adolescent populations.

Acamprosate Drug Testing

While it takes about 5 days to begin working, the effects are of acamprosate are usually dependent on dose continuation. However, acamprosate is not a controlled substance. This means that no drug testing is performed for the detection of this medication. There is a simple explanation: acamprosate simply doesn’t produce any euphoric effects and does not create tolerance, dependence, or addiction in patients who are taking it.

So, how long does acamprosate stay in your body?

For as long as you’re taking it. The half-life of a regular dose of acamprosate ranges is around 20-30 hours. Once it is metabolized, the drug leaves the system and therapeutic effects end.

Acamprosate And Addiction

There is no evidence that acamprosate produces any withdrawal symptoms in clinical trials among those who take it at therapeutic doses. Data suggests there is no evidence that this medication is eligible for abuse or dependence. In other words, taking acamprosate does not get you high.

Instead, acamprosate is used to treat addiction. Itreduces the physical and emotional discomfort many people feel in the weeks and months after they’ve stopped drinking which makes it easier for them not to drink after the immediate withdrawal period. Some of the reported effects of acamprosate include:

  • Less anxiety
  • Less mood problems
  • Less sweating
  • Less sleep disturbances

According to the National Institute on Drug Abuse, acamprosate has been shown to help dependent drinkers maintain abstinence for several weeks to months, and it may be more effective in patients with severe dependence. Still, it’s important to note that you need to go through detox before starting treatment. Use of acamprosate does not eliminate or diminish withdrawal symptoms. Speak with your doctor to learn more.

Who Should Take It

Acamprosate is most effective if you are motivated to achieve completeabstinence rather than decrease your drinking. Also, know that acamprosate works best when you’re in talk therapy and/or part of a support group community. Alcohol addiction leaves us isolated. You need to work on making social connections while using medicine if you want to get better!

Because it doesn’t interfere with opioids, acamprosate can be used if you’re also battling addiction to stronger drugs and are on medication like buprenorphine or methadone. If you’re receiving opioid maintenance therapy, at risk of relapsing opiates, or taking opioids for chronic or acute pain….acamprosate might work for you, too.

Who shouldn’t take it? Basically, anyone with hypersensitivity or an allergy to acamprosate or its components should not take acamprosate. If you have severe kidney impairment, you should also avoid the medication. Acamprosate should be prescribed with caution for:

  • Adults ages 65 and older
  • Children or adolescents.
  • Pregnant or nursing women (the benefits must outweigh the potential harm)

Problems with Acamprosate?

Acamprosate is mostly a safe medication. However, there are some possible problems that may arise in people taking it. Most common side effects of acamprosate use include:

  • Anxiety
  • Diarrhea
  • Dizziness
  • Headache
  • Flatulence
  • Insomnia
  • Intestinal cramps
  • Itchiness
  • Muscle weakness
  • Nausea

While less common, depression and suicide have also been reported in those taking acamprosate. If you experience any unusual problems while taking acamprosate, you should report these problems to a medical professional. If these symptom are severe or do not go away, call your doctor immediately.


A telltale sign of a drinking problem is continuing to drink even when you want to quit. The cravings for alcohol can be overwhelming. If you cannot stop drinking, or don’t know why you drink in the first place…help is available. Learn how professionals diagnose alcohol addiction today. And get started on the road to recovery.

Still have a questions about acamprosate? Please send us your questions in the comments section below. We try to answer all legitimate inquiries personally and promptly.

Reference Sources: Physician’s Desk Reference 60th edition, Thomson PDR, Montvale, NJ 2006., p. 1175]
NIG: TOXNET: Acamprosate
NCBI: Neuroprotective and abstinence-promoting effects of acamprosate: elucidating the mechanism of action
NCBI: Incorporating Alcohol Pharmacotherapies Into Medical Practice: Chapter 2-Acamprosate
SAMHSA: Acamprosate: A New Medication For Alcohol Use Disorders
SAMHSA: Division of Pharmacologic Therapies: Acamprosate
Medline Plus: Acamprosate
SAMHSA: TIP 49, Incorporating Alcohol Pharmacotherapies Into Medical Practice
About the author
Lee Weber is a published author, medical writer, and woman in long-term recovery from addiction. Her latest book, The Definitive Guide to Addiction Interventions is set to reach university bookstores in early 2019.
Medical Reviewers
Dr. Dili Gonzalez, M.D. is a general surgeon practicing women's focused medici...

All of the information on this page has been reviewed and verified by a licensed medical professional.

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