ACAMPROSATE CALCIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACAMPROSATE CALCIUM (ACAMPROSATE CALCIUM).
Modulates glutamatergic neurotransmission by antagonizing NMDA receptors and potentiating GABAergic activity, restoring the balance between neuronal excitation and inhibition in alcohol dependence.
| Metabolism | Not significantly metabolized. Excreted largely unchanged in urine. No known CYP450 metabolism. |
| Excretion | Renal excretion as unchanged drug: 90%; fecal: <1%; minor biliary elimination. |
| Half-life | Terminal elimination half-life: 20–30 hours; steady-state reached after 5–7 days. |
| Protein binding | Negligible (<1%); minimal protein binding. |
| Volume of Distribution | Approximately 0.6–1.0 L/kg, indicating distribution into total body water. |
| Bioavailability | Oral: 11–13% (highly variable, dose-dependent due to limited absorption). |
| Onset of Action | Oral: Clinical effect (reduction in alcohol craving) typically observed after 5–7 days of consistent dosing. |
| Duration of Action | Duration: 12–24 hours after a single oral dose; continuous use required for sustained effect. |
666 mg (two 333 mg tablets) orally three times daily, total daily dose 1998 mg. Initiate as soon as possible after abstinence is achieved; maintain for 12 months.
| Dosage form | TABLET, DELAYED RELEASE |
| Renal impairment | Contraindicated if CrCl <30 mL/min. For CrCl 30–50 mL/min: reduce to 333 mg three times daily. For CrCl >50 mL/min: no adjustment. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Safety not established in severe hepatic impairment (Child-Pugh C). |
| Pediatric use | Not approved for use in pediatric patients (<18 years). Safety and efficacy not established. |
| Geriatric use | No specific dose adjustment recommended; however, elderly patients may have reduced renal function. Assess creatinine clearance and adjust dose per renal guidelines. Monitor for adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ACAMPROSATE CALCIUM (ACAMPROSATE CALCIUM).
| Breastfeeding | Unknown if acamprosate is excreted in human breast milk. M/P ratio not established. Due to potential for adverse effects in nursing infant (e.g., diarrhea, electrolyte disturbances), breastfeeding is not recommended during therapy. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Animal studies show increased incidence of skeletal malformations and fetal growth retardation at doses equivalent to human therapeutic dose. Second trimester: Limited human data; theoretical risk of CNS effects due to calcium modulation. Third trimester: Risk of neonatal withdrawal syndrome if used near term; potential for altered calcium homeostasis in neonate. |
■ FDA Black Box Warning
None. No FDA black box warning.
| Serious Effects |
["Severe renal impairment (creatinine clearance <30 mL/min)","Hypersensitivity to acamprosate calcium or any component of the formulation"]
| Precautions | ["Suicidal ideation and behavior: Monitor for depression and suicidal thoughts","Renal impairment: Dose adjustment required in moderate impairment (CrCl 30-50 mL/min); contraindicated in severe impairment (CrCl <30 mL/min)"] |
| Food/Dietary | No significant food interactions. Can be taken with or without food. Avoid alcohol completely. |
| Clinical Pearls |
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| Fetal Monitoring | Monitor maternal renal function (serum creatinine, BUN) monthly as acamprosate is renally excreted. Fetal ultrasound for growth and anatomy if exposure occurs during first trimester. Assess for neonatal withdrawal symptoms (hyperexcitability, jitteriness) if used near delivery. |
| Fertility Effects | Animal studies show no impairment of fertility at therapeutic doses. No human data on effects on fertility or spermatogenesis. |
| Acamprosate is a synthetic taurine analog that modulates glutamate and GABA neurotransmission to reduce alcohol craving in abstinent patients. It does not treat withdrawal or produce disulfiram-like reactions. Renal function must be assessed prior to initiation; contraindicated in severe renal impairment (CrCl <30 mL/min). Dose adjustment is required for moderate impairment (CrCl 30–50 mL/min): 333 mg three times daily instead of 666 mg. Treatment should start as early as possible after withdrawal and maintained even if relapse occurs. Efficacy is best in patients with high motivation and who are already abstinent at initiation. Common side effects include diarrhea, which may resolve with dose reduction. Do not use in pregnancy unless potential benefit outweighs risk; breastfeeding not recommended. |
| Patient Advice | Take this medication exactly as prescribed, typically three times daily with or without food. · Do not drink alcohol while taking acamprosate; it does not cause sickness if you drink but reduces craving. · It may take up to 5–8 days for full effect; continue even if you do not feel immediate benefit. · Common side effects include diarrhea, nausea, and flatulence; inform your doctor if diarrhea persists. · Avoid driving or operating machinery if you experience dizziness or drowsiness. · Do not stop suddenly; consult your doctor before discontinuing. · Inform your doctor about all other medications, especially antidepressants or blood pressure drugs. · Store at room temperature, away from moisture and heat. |