Schedule H

Oral

Formulation Type Strengths Available

Enteric-Coated Tablets 333 mg (as Acamprosate Calcium)

Note: Acamprosate is available as single-agent enteric-coated tablets only. Tablets should be swallowed whole and not crushed.

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Alcohol Dependence — Maintenance of Abstinence

Used as adjunct to psychosocial interventions in patients who have achieved initial alcohol abstinence.

Prerequisites before initiation:

• Patient must have achieved initial alcohol abstinence (ideally after completion of detoxification)

• Best efficacy when started within 1 week of abstinence

• Concurrent psychosocial therapy programme in place

• Baseline renal function confirmed

Parameter Dosing

Starting dose 666 mg (two 333 mg tablets) three times daily with meals

Titration No titration required; start at full dose if tolerated

Usual maintenance dose 666 mg three times daily (total 1998 mg/day)

Maximum dose 1998 mg/day

Weight-Based Dosing:

Body Weight Recommended Dose

≥60 kg 666 mg three times daily (1998 mg/day)

<60 kg 333 mg three times daily (999 mg/day)

Clinical Notes:

• Continue treatment for minimum 6–12 months as part of comprehensive relapse prevention strategy

• Efficacy is optimal when treatment is initiated promptly after detoxification

• Can be continued even if patient relapses to drinking — does not cause disulfiram-like reaction

• Unlike disulfiram, does not require abstinence for safety; unlike naltrexone, does not block opioid effects

• May take several weeks to achieve full therapeutic effect

Secondary Indications — Adults (Off-label)

Not applicable. No established off-label indications documented in Indian clinical practice.

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

Not applicable. Acamprosate is NOT approved for use in children and adolescents.

Secondary Indications — Paediatric (Off-label)

Not applicable.

Clear Statement: Use in patients below 18 years of age is NOT RECOMMENDED. Safety and efficacy have not been established in the paediatric population. Alcohol use disorders in adolescents should be managed primarily with psychosocial interventions under specialist supervision.

Note: Renal function should be assessed before initiating therapy and monitored periodically during treatment.

Note: Acamprosate is NOT hepatically metabolised and does NOT cause hepatotoxicity. This makes it particularly suitable for patients with alcoholic liver disease (provided renal function is adequate). This is a key advantage over disulfiram and naltrexone.

• Severe renal impairment (eGFR/CrCl <30 mL/min)

• Known hypersensitivity to acamprosate calcium or any excipient

• Currently drinking or in acute alcohol withdrawal (should only be started after detoxification)

• Moderate renal impairment — requires dose reduction

• History of depression or suicidal ideation — monitor psychiatric status closely, especially in early treatment

• Elderly patients — more likely to have reduced renal function

• Dehydration or conditions predisposing to electrolyte imbalance — may affect renal clearance

• Concurrent use with other anti-craving medications (naltrexone, disulfiram) — limited data; weigh risk-benefit

• Patients with poor motivation or unreliable for follow-up — efficacy depends on adherence and concurrent psychosocial support

Parameter Details

Risk category Limited human data; animal studies suggest possible adverse fetal effects; use only if clearly needed

Preferred alternatives Non-pharmacological interventions (psychosocial therapy, motivational interviewing) are first-line; naltrexone may be considered in second/third trimester under specialist supervision if pharmacotherapy essential

When it may be used Only if maternal benefit clearly outweighs fetal risk; specialist psychiatry and obstetric supervision mandatory

Monitoring Fetal growth ultrasound; maternal renal function

Parameter Details

Compatibility NOT recommended during breastfeeding

Drug levels in milk Unknown; excretion in human milk not studied

Preferred alternatives Non-pharmacological interventions; if pharmacotherapy essential, naltrexone may be considered with monitoring

Monitoring in infant If inadvertent exposure: gastrointestinal disturbances, feeding difficulties, sedation (theoretical)

Parameter Recommendation

Starting dose 333 mg three times daily (especially if body weight <60 kg or renal function borderline)

Titration Assess tolerance after 1–2 weeks; may increase to standard dose if renal function adequate

Extra risks Higher prevalence of reduced renal function; increased risk of dehydration; cognitive impairment may affect adherence; monitor creatinine more frequently

Special considerations Check renal function before starting and periodically during treatment; frail elderly may require lower doses indefinitely

Interacting Drug Effect Recommendation

No major clinically significant interactions documented Acamprosate undergoes minimal hepatic metabolism and does not affect CYP450 enzymes Drug-drug interactions are unlikely; this is a key advantage of acamprosate

Note: Acamprosate may be used concurrently with disulfiram or naltrexone if clinically indicated, though combined efficacy data is limited. Monitor adherence and tolerance when combining.

Interacting Drug Effect Recommendation

CNS Depressants (Benzodiazepines, Opioids, Sedative-Hypnotics) No direct pharmacokinetic interaction, but additive CNS effects possible in patients with comorbid conditions Use with caution; monitor for excessive sedation

Antidepressants No pharmacokinetic interaction expected Monitor mood and suicidal ideation, especially in early treatment phase

Naltrexone No significant interaction; may have complementary mechanisms Can be used together under specialist supervision

Disulfiram No pharmacokinetic interaction Can be used together; monitor adherence to both medications

• Diarrhoea (most common — often dose-related and occurs early in treatment)

• Nausea

• Flatulence

• Abdominal pain, abdominal discomfort

• Pruritus

• Maculopapular rash

• Insomnia

• Headache

• Decreased libido

• Acute Kidney Injury — especially in dehydrated patients or those with pre-existing renal impairment; monitor renal function

• Severe Diarrhoea — may require discontinuation if persistent and unmanageable

• Suicidal Ideation or Behaviour — rare but reported; monitor psychiatric status closely, especially in patients with history of depression

• Severe Allergic Reactions — angioedema, urticaria (rare); requires discontinuation

Phase Parameters to Monitor

Baseline Renal function (serum creatinine, eGFR), body weight, psychiatric assessment (including suicidal ideation screening), confirmation of alcohol abstinence

After initiation (1–2 weeks) GI tolerability (especially diarrhoea), medication adherence, abstinence status

Short-term (Monthly for first 3 months) Renal function, clinical assessment for relapse, mood and behavioural status

Long-term (Quarterly thereafter) Renal function, abstinence verification, ongoing psychosocial engagement, psychiatric status

Note: Acamprosate is available as single-agent enteric-coated tablets only. No fixed-dose combinations are marketed in India.

Note: Acamprosate is NOT included in NLEM India 2022; prices are not NPPA-controlled. Available at subsidised rates in some government psychiatry and de-addiction programmes.

• Start after abstinence is achieved: Unlike disulfiram, acamprosate does not cause a reaction with alcohol, but efficacy is best when started promptly after detoxification (ideally within 1 week).

• Diarrhoea is the limiting adverse effect: Most common reason for discontinuation; often improves after first 2–3 weeks; advise patients to persist if tolerable.

• No hepatotoxicity — preferred in liver disease: Unlike disulfiram and naltrexone, acamprosate is not hepatically metabolised and does not cause liver injury; ideal for patients with alcoholic liver disease (provided renal function is adequate).

• Renal function is the key determinant: Always check renal function before starting; contraindicated if eGFR <30 mL/min.

• No abuse or dependence potential: Acamprosate has no reinforcing properties and is not a controlled substance.

• Works best with psychosocial support: Emphasise that medication alone is insufficient — concurrent counselling, group therapy, or structured de-addiction programme significantly improves outcomes.

Acamprosate; alcohol dependence; relapse prevention; abstinence maintenance; de-addiction; GABA modulator; hepatic-safe; renal-dose-adjust; psychiatry-caution; Schedule H; Psychiatry

RxIndia v1.0 — 11 Jun 2025

• CDSCO approved product inserts

• Indian Pharmacopoeia / National Formulary of India

• API Textbook of Medicine — Psychiatry chapter

• AIIMS Psychiatry De-addiction Protocols

• Government of India Guidelines for Treatment of Substance Use Disorders

• ICMR/WHO Alcohol Use Disorder Treatment Guidelines (supportive reference)

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Harrison's Principles of Internal Medicine, 21st edition