Acamprosate Starting Dose
The recommended starting dose of acamprosate for an adult patient with normal liver and renal function is 666 mg (two 333 mg tablets) taken three times daily, for a total daily dose of 1998 mg. 1
Standard Dosing Protocol
- The FDA-approved regimen is two 333 mg tablets taken three times daily (666 mg per dose, 1998 mg total daily). 1
- Dosing may be done without regard to meals, though taking acamprosate with meals was used in clinical trials and is suggested for patients who regularly eat three meals daily. 1
- Treatment should be initiated as soon as possible after the period of alcohol withdrawal, when the patient has achieved abstinence—specifically 3-7 days following the last episode of alcohol consumption and after withdrawal symptoms have resolved. 2, 3
Weight-Based Dosing Considerations
- For patients weighing ≥60 kg: the full dose of 1998 mg/day is appropriate. 2
- For patients weighing <60 kg: the dose should be reduced by one-third to 1332 mg/day (one 333 mg tablet three times daily). 2
Critical Timing Requirements
A common pitfall is starting acamprosate too early. The patient must be:
- Completely detoxified from alcohol 1
- Already abstinent at treatment initiation 1
- Past the acute withdrawal phase (3-7 days after last drink) 2, 3
Acamprosate does not treat withdrawal symptoms and is ineffective in promoting abstinence in patients who have not undergone detoxification. 1
Renal Function Adjustments
While your question specifies normal renal function, be aware that:
- Moderate renal impairment (CrCl 30-50 mL/min): reduce to 333 mg three times daily 1
- Severe renal impairment (CrCl ≤30 mL/min): acamprosate is contraindicated 1
- Acamprosate is renally excreted without hepatic metabolism, making renal function the only organ system requiring dose adjustment. 4
Hepatic Safety Advantage
Acamprosate is particularly advantageous in patients with liver disease because it has no hepatic metabolism and no reported hepatotoxicity. 3, 4 This contrasts with naltrexone (contraindicated in alcoholic liver disease) and disulfiram (should be avoided in severe alcoholic liver disease). 3
Treatment Duration and Continuation
- The typical treatment period is 3-6 months, though it can extend up to 12 months. 2
- Steady-state plasma concentrations are reached within 5-7 days (some sources indicate 1-2 weeks). 2, 5
- Treatment should be maintained even if the patient relapses—this is a critical point that differs from some other addiction medications. 1
- Acamprosate must be used as part of a comprehensive psychosocial treatment program. 1
Pharmacokinetic Rationale
The three-times-daily dosing is based on acamprosate's pharmacokinetic profile, with a terminal elimination half-life requiring multiple daily doses to maintain therapeutic levels. 5 While some research suggests twice-daily dosing may be bioequivalent, the FDA-approved and guideline-supported regimen remains three times daily. 6