Acamprosate Calcium

Class and Category

Pharmacologic class: Amino acid neurotransmitter analogue

Therapeutic class: Alcohol deterrent

Indications and Dosages

To maintain abstinence from alcohol for alcohol-dependent patients who are abstinent at the start of treatment

EXTENDED RELEASE (E.R) TABLETS

Adults. 666 mg three times daily.

DOSAGE ADJUSTMENT For patients with moderate renal impairment (creatinine clearance of 30 to 50 ml/min), initial dosage reduced to 333 mg three times daily.

Route : P.O.

Onset : Unknown

Peak : 3–8 hr

Duration : Unknown

Contraindications

Hypersensitivity to acamprosate or its components, severe renal impairment (creatinine clearance 30 ml/min or less)

Interactions

DRUGS

None reported

Adverse Reactions

CNS: Abnormal thinking, amnesia, anxiety, asthenia, chills, depression, dizziness, headache, insomnia, paresthesia, somnolence, suicidal ideation, syncope, tremor

CV: Chest pain, hypertension, palpitations, peripheral edema, vasodilation

EENT: Abnormal vision, dry mouth, pharyngitis, rhinitis, taste perversion

GI: Abdominal pain, anorexia, constipation, diarrhea, flatulence, increased appetite, indigestion, nausea, vomiting

GU: Acute renal failure, decreased libido, impotence

HEME: Leukopenia, lymphocytosis, thrombocytopenia

MS: Arthralgia, back pain, myalgia

RESP: Bronchitis, cough, dyspnea

SKIN: Diaphoresis, pruritus, rash

Other: Flu-like symptoms, infection, weight gain

Childbearing Considerations

PREGNANCY

It is not known if drug causes fetal harm but animal studies suggest it may. Use with caution only if benefit to mother outweighs potential risk to fetus.

LACTATION

It is not known if drug is present in breast milk. Patient should check with prescriber before breastfeeding.

Nursing Considerations

• Know that acamprosate should start as soon as possible after patient has undergone alcohol withdrawal and achieved abstinence.
• Continue to give acamprosate even during periods of alcohol relapse, as ordered.

PATIENT TEACHING

• Instruct patient to take acamprosate exactly as prescribed, even if a relapse occurs, and to seek help for a relapse.
• Tell patient to take tablet whole and not to crush, split, or chew it.
• Warn patient that acamprosate won’t reduce symptoms of alcohol withdrawal if relapse occurs followed by cessation.
• Urge caregivers to monitor patient for evidence of depression (lack of appetite or interest in life, fatigue, excessive sleeping, difficulty concentrating) or suicidal tendencies because a small number of patients taking acamprosate have attempted suicide.
• Advise patient to use caution when performing hazardous activities until adverse CNS effects of drug are known.
• Tell female patient to notify prescriber if she is or intends to become pregnant while taking acamprosate; the drug may need to be stopped because fetal risks are unknown.

Mechanism of Action

• Chronic alcoholism may alter the balance between excitation and inhibition in neurons in the brain; acamprosate restores it. When the neurotransmitter gamma-aminobutyric acid (GABA) binds to its receptors in the CNS, it opens the chloride ion channel and releases chloride (Cl–) into the cell (below left), thereby reducing neuronal

• When glutamate binds to its receptors, it closes the chloride ion channel, increasing neuronal excitability by promoting depolarization (below left). This imbalance fosters a craving for alcohol. By interacting with glutamate receptor sites, acamprosate prevents glutamate from binding (below right).