Is acamprosate appropriate for a patient receiving buprenorphine (Sublocade) with an estimated glomerular filtration rate ≥30 mL/min and no contraindications?

Yes, acamprosate is an appropriate option for this patient.

Acamprosate can be safely used in patients with eGFR ≥30 mL/min, though dose adjustment is required for moderate renal impairment (eGFR 30-50 mL/min). 1 Since your patient has eGFR ≥30 mL/min and no contraindications, acamprosate is a viable medication for alcohol use disorder maintenance therapy.

Dosing Based on Renal Function

• If eGFR ≥50 mL/min: Standard dosing of 666 mg (two 333 mg tablets) three times daily 1
• If eGFR 30-50 mL/min: Reduced dose of 333 mg (one tablet) three times daily 1
• If eGFR <30 mL/min: Contraindicated 1

The FDA label is explicit that acamprosate is contraindicated only when creatinine clearance is ≤30 mL/min, making it safe for your patient with eGFR ≥30 mL/min. 1

Key Clinical Considerations

Acamprosate has distinct advantages in this clinical scenario:

• No hepatic metabolism: Acamprosate is not metabolized by the liver and is excreted unchanged by the kidneys, making it particularly suitable for patients with hepatic impairment (common in alcohol use disorder) 2, 3
• No interaction with buprenorphine: Acamprosate's mechanism involves glutamate/GABA modulation rather than opioid receptor activity, so there are no pharmacological interactions with buprenorphine 2, 4
• Can be used during active drinking: Unlike naltrexone, acamprosate is not impacted by alcohol use and can be administered even if the patient relapses 2

Important Prescribing Requirements

Treatment must begin after alcohol detoxification and abstinence is achieved. 1 Acamprosate has not been shown effective in patients who have not undergone detoxification or achieved abstinence prior to starting treatment. This is a critical point—the patient must be abstinent when initiating therapy.

Acamprosate should be part of comprehensive psychosocial treatment. 1 The medication alone is insufficient; it must be combined with counseling, support groups, or other behavioral interventions.

Monitoring and Safety

Monitor for depression and suicidality. In controlled trials, suicidal ideation and attempts were more common with acamprosate (1.4% vs 0.5% in short-term studies; 2.4% vs 0.8% in year-long studies) compared to placebo. 1 Alert the patient and family to report any emergence of depressive symptoms or suicidal thinking.

Monitor renal function periodically, particularly if the patient is on the reduced dose regimen or has borderline renal function. 1

Common side effects include diarrhea, which is generally manageable and often improves with continued use. 1

Practical Dosing Considerations

The standard three-times-daily dosing can be challenging for adherence. While the FDA label recommends dosing without regard to meals, dosing with meals was used in clinical trials and may improve adherence in patients who eat three regular meals daily. 1

Recent evidence suggests that reduced-frequency dosing (500 mg twice daily) may be bioequivalent to traditional dosing, though clinical efficacy data for this regimen is limited. 5 For now, stick with FDA-approved dosing unless adherence becomes a significant barrier.

Contraindications to Verify

Ensure the patient has no history of hypersensitivity to acamprosate or any of its components. 1 Note that acamprosate contains sulfites, which may cause allergic reactions in susceptible individuals, particularly those with asthma. 1