Acamprosate for Alcohol Use Disorder: A Comprehensive Guide

Introduction

Acamprosate represents a well-established, evidence based, pharmacological intervention for maintaining abstinence in patients with Alcohol Use Disorder (AUD). This guide provides medical practitioners with essential information for effectively incorporating Acamprosate into treatment plans for patients with AUD.

Mechanism of Action

Acamprosate operates through a unique neurochemical pathway that differs from other anti-craving medications:

1. Normalizes the balance between excitatory (glutamate) and inhibitory (GABA) neurotransmission disrupted by chronic alcohol use
2. Reduces glutamatergic hyperactivity that occurs during alcohol withdrawal and early abstinence
3. Attenuates the neurochemical dysregulation associated with protracted withdrawal
4. Helps stabilize the brain’s neurochemistry as it adapts to the absence of alcohol

Unlike disulfiram, Acamprosate is not an aversive agent. Patients will not experience adverse physical reactions if they consume alcohol while taking Acamprosate. The medication works primarily by reducing persistent cravings rather than creating negative associations with alcohol consumption.

• Acamprosate is slowly absorbed from the gastrointestinal tract over a period of four hours. 
• Peak concentrations are reached after five to seven hours and steady state levels are achieved after seven days. 
• Acamprosate is not metabolised significantly in the liver and is excreted unchanged in the urine. 
• Elimination half-life of Acamprosate is between 13 and 28 hours.

Clinical Efficacy

Research consistently demonstrates that Acamprosate:

• Significantly increases rates of abstinence from alcohol
• Extends the duration of abstinence periods
• Reduces the intensity of cravings, particularly after initial detoxification
• Demonstrates most benefit in patients committed to abstinence goals
• Shows greatest efficacy when initiated after the completion of alcohol withdrawal

Acamprosate has demonstrated particular effectiveness for patients with high levels of anxiety and those with more severe alcohol dependence. It appears to be less useful for episodic heavy drinkers. The medication must be integrated into a comprehensive treatment program that includes psychological support, education and counselling.

Prescribing Guidelines

Dosage and Administration

The recommended adult dosage for Acamprosate is:

• 666mg (two 333mg tablets) three times daily for patients ≥60kg (Alternatively 999mg twice daily if compliance is poor)
• 666mg in the morning, 333mg at noon, and 333mg in the evening for patients <60kg (Alternatively if <60kg: 666mg twice daily). 

Key administration considerations include:

• Acamprosate should be taken with meals to improve adherence and reduce gastrointestinal side effects
• Treatment should be initiated as soon as possible after the completion of alcohol withdrawal
• Optimal treatment duration is typically 6-12 months, though longer durations may be appropriate based on clinical response
• Effectiveness should be reassessed regularly. 

Precautions

Acamprosate requires dose adjustments based on renal function:

Normal renal function (CrCl >80 mL/min):

• Standard dose: 666 mg three times daily

Mild renal impairment (CrCl 50-80 mL/min):

• 333 mg three times daily

Moderate renal impairment (CrCl 30-49 mL/min):

• 333 mg twice daily

Severe renal impairment (CrCl <30 mL/min):

• Contraindicated

Monitor renal function in patients regularly, especially in older adults and those with existing renal conditions.

Contraindications

Acamprosate is contraindicated in:

• Patients with severe renal impairment (creatinine clearance <30ml/min)
• Hypersensitivity to Acamprosate or its components
• Pregnancy and breastfeeding (safety not established)

Side Effect Profile

Acamprosate is generally well-tolerated with a favorable safety profile:

• Most common side effect is diarrhea (reported in 10-15% of patients), typically mild to moderate and transient
• Other reported effects include abdominal pain, nausea, headache, pruritus, and fluctuations in libido
• No significant drug interactions have been documented
• No development of tolerance or dependence
• No risk of abuse or diversion

The safety profile makes Acamprosate suitable for patients with hepatic impairment, unlike many other medications used in AUD treatment.

Patient Selection and Clinical Considerations

Acamprosate may be particularly beneficial for:

• Patients with a goal of complete abstinence rather than reduced consumption
• Individuals with anxiety symptoms during early sobriety
• Patients with hepatic impairment who cannot tolerate Naltrexone
• Those requiring long-term pharmacological support for maintaining abstinence
• Patients taking opioid medications who cannot use Naltrexone

Important clinical considerations when prescribing Acamprosate include:

1. The medication demonstrates optimal efficacy when initiated after completion of detoxification
2. Unlike Naltrexone, Acamprosate does not interfere with opioid medications
3. The three-times-daily dosing regimen may present adherence challenges for some patients
4. Therapeutic effects may take 1-2 weeks to become apparent
5. Continued abstinence remains the goal, but treatment should not be discontinued if relapse occurs

Patient Education

When prescribing Acamprosate, ensure patients understand:

• The medication helps reduce cravings but does not prevent intoxication if alcohol is consumed
• No adverse reactions will occur if alcohol is consumed while taking Acamprosate
• Consistent medication adherence is essential for effectiveness
• The importance of continuing the medication even if cravings are reduced
• The medication works best as part of a comprehensive treatment approach

Practical Implementation in General Practice

Successful integration of Acamprosate therapy into general practice includes:

1. Establishing clear treatment goals and expectations with the patient
2. Addressing potential adherence challenges of the three-times-daily dosing schedule
3. Regular follow-up appointments to monitor effectiveness, side effects, and adherence
4. Coordination with addiction specialists when appropriate
5. Integration with psychosocial interventions for optimal outcomes

Conclusion

Acamprosate offers general practitioners an effective, evidence-based tool for supporting patients with Alcohol Use Disorder, particularly those seeking to maintain long-term abstinence. With a favorable safety profile, minimal drug interactions, and proven efficacy, Acamprosate represents an important option in the pharmacological management of AUD.

For comprehensive prescribing information, download our Acamprosate Clinician Information Sheet below. Additionally, a Patient Handout is available to facilitate informed discussions with your patients about Acamprosate therapy.