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Acamprostate calcium (Campral®)

Volume VII, Number 6 | November/December 2004

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Acamprosate calcium (Campral^®; Forest Laboratories) is a new oral medication indicated for the maintenance of abstinence from alcohol in patients with alcohol dependence who are abstinent at treatment initiation. Acamprosate is the third medication, after disulfiram (Antabuse^®) and naltrexone (ReVia^®), to be approved by the Food and Drug Administration (FDA) for the treatment of alcohol dependence. Unapproved drugs for this indication include nalmefene (Revex^®), topiramate (Topamax^®), and clonidine (Catapres^®).

Acamprosate has not been fully assessed for use in promoting alcohol abstinence in multiple substance abusers. Additionally, there is no evidence of acamprosate promoting abstinence in patients who have not undergone detoxification and have not achieved alcohol abstinence prior to beginning treatment. A specific duration of therapy has not yet been determined.

The mechanism of action of acamprosate in the treatment of alcohol dependence is not well understood. It is thought, however, that it affects both gamma aminobutyric acid (GABA) and glutamate activity. Animal studies suggest that acamprosate interacts with GABA and glutamate and thus restores the normal balance between neuronal excitation and inhibition that is altered in chronic alcohol abuse. Additionally, acamprosate has been shown in animal models to reduce alcohol consumption, whereas in humans it has been shown to enhance abstinence and reduce drinking rates.

The most common adverse effect of acamprosate is diarrhea (10-17%). Other adverse effects noted in trials include asthenia, nausea, anxiety, depression, dizziness, insomnia, and pruritus. Clinical trials showed that the risk of suicide was higher in acamprosate-treated patients than with placebo and although the combination of alcohol dependence, depression, and suidicality is well-recognized, the risk of suicide has been documented as a precaution.

Treatment with acamprosate should be started as soon as alcohol abstinence occurs and should be maintained even if the patient relapses. Acamprosate should be used in conjunction with psychosocial support. The recommended dose of acamprosate is two 333 mg tablets (total dose of 666 mg) administered orally three times daily. Dosing with meals may aid in compliance for patients who regularly eat three meals per day, however it may be taken without regard to meals. Acamprosate should be initiated at a dose of one 333 mg tablet administered orally three times daily for patients with moderate renal impairment (CrCl = 30-50 ml/min) and is contraindicated in patients with severe renal impairment (CrCl < 30 ml/min).

Acamprosate is available as a delayed-release, enteric-coated tablet and was FDA-approved in July 2004. Acamprosate has not been formally reviewed for addition to the CCF Formulary of Accepted Drugs.

Table 1: Cost Comparison of Select Agents for Treatment of Alcohol Dependence

F=Formulary
NF=Non-formulary
AWP=Average Wholesale Price
TID=Three Times Daily

Thanks to Silvana Balliu, R.Ph. for assistance in writing this article on acamprosate.

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