U.S. Brand Names Campral

Synonyms Acamprosate Calcium; Calcium Acetylhomotaurinate

Therapeutic Category
GABA Agonist/Glutamate Antagonist
Use Maintenance of alcohol abstinence

Pregnancy Risk Factor C

Pregnancy Implications Teratogenic in animal studies. No adequate or well controlled studies in pregnant women, use only if potential benefit outweighs possible risk to the fetus.

Contraindications Hypersensitivity to acamprosate or any component of the formulation; severe renal impairment (Clcr<30 mL/minute)

Warnings/Precautions Should be used as part of a comprehensive program to treat alcohol dependence. Treatment should be initiated as soon as possible following the period of alcohol withdrawal, when the patient has achieved abstinence. Does not eliminate or diminish the symptoms of alcohol withdrawal. Use caution in moderate renal impairment (Clcr 30-50 mL/minute). Suicidal ideation, attempts and completed suicides have occurred in acamprosate-treated patients; monitor for depression and/or suicidal thinking. Traces of sulfites may be present in the formulation. Safety and efficacy not established in pediatric patients.

Adverse Reactions
Note: Many adverse effects associated with treatment may be related to alcohol abstinence; reported frequency range may overlap with placebo.

>10%: Gastrointestinal: Diarrhea (10% to 17%)

1% to 10%: Cardiovascular: Syncope, palpitation, edema (peripheral)
Central nervous system: Insomnia (6% to 9%), anxiety (5% to 8%), depression (4% to 8%), dizziness (3% to 4%), dry mouth (1% to 3%), pain (2% to 4%), paresthesia (2% to 3%), headache, somnolence, amnesia, tremor, chills
Dermatologic: Pruritus (3% to 4%), rash
Endocrine and metabolic: Weight gain, libido decreased
Gastrointestinal: Anorexia (2% to 5%), flatulence (1% to 3%), nausea (3% to 4%), abdominal pain, vomiting, dyspepsia, constipation, appetite increased, taste perversion
Genitourinary: Impotence
Miscellaneous: Sweating (2% to 3%), suicide attempt
Neuromuscular & skeletal: Weakness (5% to 7%), back pain, myalgia, arthralgia
Ocular: Abnormal vision
Respiratory: Rhinitis, dyspnea, pharyngitis, bronchitis

<1%, Postmarketing and/or case reports (limited to significant or life-threatening): Angina, asthma, exfoliative dermatitis, gastrointestinal hemorrhage, hallucinations, hypothyroidism, myocardial infarction, ophthalmitis, pancreatitis, photosensitivity, psychosis, pulmonary embolus, renal calculus, renal failure, seizures, suicidal ideation, suicide attempts, completed suicide

Drug Interactions

No clinically significant drug-drug interactions have been identified.

Based on calcium content, the following interactions may occur:Levothyroxine: Calcium carbonate (and possibly other calcium salts) may decrease T4 absorption; separate dose from levothyroxine by at least 4 hours
Polystyrene sulfonate: Potassium-binding ability is reduced; avoid concurrent use.
Tetracycline, atenolol (and potentially other beta-blockers), iron, quinolone antibiotics, alendronate, sodium fluoride, and zinc absorption is significantly decreased; space administration times.

Food Interactions

Ethanol: Abstinence is required during treatment. Ethanol does not affect the pharmacokinetics of acamprosate.

Food: Food decreases absorption of acamprosate (not clinically significant)

Mechanism of Action Mechanism not fully defined. Structurally similar to gamma-amino butyric acid (GABA), acamprosate appears to increase the activity of the GABA-ergic system, and decreases activity of glutamate within the CNS, including a decrease in activity at N-methyl D-aspartate (NMDA) receptors. May also affect CNS calcium channels. Restores balance to GABA and glutamate activities which appear to be disrupted in alcohol dependence. During therapeutic use, reduces alcohol intake but does not cause a disulfiram-like reaction following alcohol ingestion.

Pharmacodynamics/Kinetics

Distribution: Vd: 1 L/kg

Protein binding: Negligible

Metabolism: Not metabolized

Bioavailability: 11%

Half-life: 20-33 hours

Excretion: In urine, as unchanged drug

Usual Dosage

Adults: Oral: Alcohol abstinence: 666 mg 3 times/day. A lower dose may be effective in some patients. Adjustment in patients with low body weight (unlabeled): A lower dose (4 tablets/day) may be considered in patients with low body weight (ie, <60 kg).
Note: Treatment should be initiated as soon as possible following the period of alcohol withdrawal, when the patient has achieved abstinence.

Dosage adjustment in renal impairment: Clcr 30-50 mL/minute: Initial dose should be reduced to 333 mg 3 times/day. Contraindicated in severe renal impairment (Clcr<30 mL/minute).

Dietary Considerations May be taken without regard to meals. Each 333 mg tablet contains 33 mg of elemental calcium.

Dosage Forms Tablet, enteric coated, as calcium: 333 mg [contains calcium 33 mg and sulfites]