Acamprosate

Acamprosate is a prescription drug used for the treatment of alcohol dependence. It is thought to balance neurotransmission in the brain. Neurotrasnmission is the process by which neurons communicate with one another. Acamprosate was used in Europe for several years before the U.S. Food and Drug Administration approved acamprosate in September 2004. It is only one of three drugs approved in the United States for this condition.

Other Names

Acamprosate is marketed by Forest Laboratories in the United States and by Merck in other countries. The brand name of acamprosate is Campral.

Uses

Acamprosate is used in conjunction with support groups to maintain abstinence from alcohol in people with alcohol dependence.

How Acamprosate is Taken

Acamprosate is available in 333 mg oral tablets. The recommended dose is two 333 mg tablets taken three times daily.

How Acamprosate Works

Chronic alcohol exposure is believed to alter the balance between excitation and inhibition of neurons (nerve cells) in the brain. Excitation of neurons increases their electrical activity and the probability that the neurons will stimulate other neurons. Inhibition reduces the electrical activity of neurons making them less likely to activate. Many neurons are activated by a receptor called N-methyl-D-aspartate (NMDA) and many are inhibited by receptors called gamma-amino butyric acid (GABA). Imbalances in the activation of NMDA and GABA receptors may lead to alcohol dependence.

Acamprosate is structurally similar to GABA, the chemical that activates GABA receptors. The mechanism of acamprosate is unclear, but it is thought to activate GABA receptors and restore the balance between NMDA-induced neuronal activation and GABA-induced neuronal inhibition.

How the Body Affects Acamprosate

Peak circulating levels of acamprosate are reached at 3–8 hours post-dosing. The half-life of acamprosate, or the time needed for the concentration of the drug in the blood to be reduced by half, is approximately 18 hours. Acamprosate Is not metabolized and is primarily excreted in the urine.

Side Effects

The most common side effects of acamprosate, occurring in 3% or more of people, are the following:

• accidental injury
• feelings of weakness
• pain
• anorexia (loss of appetite)
• diarrhea
• flatulence
• nausea
• anxiety
• depression
• dizziness
• dry mouth
• insomnia
• tingling sensations
• itching
• sweating

Risks and Precautions

Drugs like acamprosate that affect the brain’s chemistry may impair judgment, thinking, or motor skills.

The effects of acamprosate on the fetus are not known. Similarly, it is not known if acamprosate crosses into breast milk.

Drug Interactions

Co-administered naltrexone increases the blood concentration of acamprosate, probably by slowing the emptying of stomach contents into the small intestine. This interaction is unlikely to change the safety or effectiveness of acamprosate.

Alternatives

In the United States, only two other drugs, disulfiram (Antibuse) and naltrexone (Revia), are approved to treat alcohol dependence. Disulfiram is used less frequently today because of side effects and high discontinuation rate among users.

A multicenter study of people recovering from alcohol dependence found that acamprosate had no influence on recovery, whereas naltrexone improved symptoms of depression and anxiety and lengthened time to relapse in patients with low-depression and low0-dependence.^[1]

Research

In three of four trials, acamprosate plus support group therapy proved more effective to support group therapy alone in maintaining alcohol abstinence.^[2]

The COMBINE trial was a large, multicenter study that looked at the effectiveness of medications and behavioral therapies, or the combination of these, in the management of recovery from alcohol dependence.^[3] Interventions with acamprosate, naltrexone, behavioral therapy, or placebo all had reduced the amount of drinking. Acamprosate, either alone or in combination with behavioral therapy or other medical management, had no effect on the number of days before relapse or the number of heavy drinking days. However, naltrexone treatment alone or in combination with other medical management or behavioral therapy improved both these outcomes significantly.

References

1. ↑ Morley KC, Teesson M, Reid SC, et al. Naltrexone versus acamprosate in the treatment of alcohol dependence: A multi- centre, randomized, double-blind, placebo-controlled trial. Addiction. 2006 Oct;101(10):1451-62. Abstract
2. ↑ About.com. Campral Now Available for Alcoholism Treatment.
3. ↑ 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 May 3;295(17):2003-17. Abstract | Full Text | PDF

External Links

FDA: Patient Information Sheet