What is the recommended dosage of gabapentin (Gabapentin) for an adult patient with alcohol use disorder (AUD) and no significant medical contraindications?

Gabapentin Dosing for Alcohol Use Disorder

For adults with alcohol use disorder, gabapentin should be dosed at 1800 mg/day (600 mg three times daily) for optimal efficacy in reducing heavy drinking and maintaining abstinence, particularly in patients with a history of alcohol withdrawal symptoms.

Evidence-Based Dosing Strategy

Target Dose and Titration

The most effective gabapentin regimen for AUD is 1800 mg/day in divided doses, based on the highest quality randomized controlled trial data 1. This dose demonstrated:

• 17% abstinence rate vs 4.1% with placebo (NNT = 8) 1
• 44.7% no heavy drinking rate vs 22.5% with placebo (NNT = 5) 1
• Clear dose-response relationship, with 1800 mg significantly superior to 900 mg 1

Practical Titration Schedule

Start conservatively and titrate upward over 1-2 weeks 1:

• Week 1: Begin 300 mg three times daily (900 mg/day total)
• Week 2: Increase to 600 mg three times daily (1800 mg/day total)
• Monitor for dizziness and sedation during titration 1

This approach balances efficacy with tolerability, as gabapentin has nonlinear pharmacokinetics requiring careful dose escalation 2.

Patient Selection: Who Benefits Most

High Alcohol Withdrawal Symptom Patients

Gabapentin is most efficacious in patients with significant alcohol withdrawal history 3. In those meeting multiple DSM-5 alcohol withdrawal criteria:

• 27% achieved no heavy drinking days vs 9% with placebo (NNT = 3.1) 3
• 18% achieved total abstinence vs 4% with placebo (NNT = 2.7) 3

Patients with low withdrawal symptoms showed no significant benefit from gabapentin 3, making withdrawal history a critical selection criterion.

Additional Benefits Beyond Drinking Reduction

Gabapentin at 1800 mg/day provides dose-dependent improvements in 1:

• Insomnia (a common relapse trigger)
• Dysphoria and mood symptoms
• Alcohol craving

These secondary effects likely contribute to its efficacy in maintaining sobriety 1.

Safety Considerations and Monitoring

Common Adverse Effects

Gabapentin causes dose-dependent dizziness and sedation, which can be minimized through gradual titration 2, 1. In the pivotal trial, there were no serious drug-related adverse events, and only 6% of participants discontinued due to side effects 1.

Falls and Altered Mental Status Risk

Monitor carefully for falls/fractures and cognitive changes, especially at doses ≥600 mg/day 4:

• Falls/fractures incidence: 1.81 per 100 person-years (RR 1.35 vs unexposed) 4
• Risk increases with dose, highest at ≥2400 mg/day (RR 1.90) 4
• Altered mental status: RR 1.12 overall, significant at 600-2399 mg/day 4

Renal Dosing Adjustment

Reduce dose in renal insufficiency based on creatinine clearance, as gabapentin is renally eliminated 2. This is critical to avoid drug accumulation and toxicity.

Dependence Potential

While generally well-tolerated, gabapentin can cause physiologic dependence requiring prolonged tapers (up to 18 months in severe cases) 5. Avoid abrupt discontinuation in patients on long-term therapy.

Guideline Context and Alternatives

Limited Guideline Support

The 2018 EASL guidelines acknowledge gabapentin has been tested for AUD but note "no consistent results in large samples have been reported" 2. However, this predates the 2020 high-quality RCT demonstrating clear efficacy in withdrawal-prone patients 3.

Comparison to Other Agents

Current guideline-supported options include 2:

• Baclofen: 30-80 mg/day, only agent tested in cirrhotic patients, but mixed efficacy data 2, 6
• Topiramate: Effective but not tested in liver disease 2
• Benzodiazepines: Gold standard for acute withdrawal only (10-14 days maximum) 2

Gabapentin offers advantages over these alternatives: it has demonstrated efficacy at therapeutic doses, favorable safety profile without abuse liability concerns of benzodiazepines, and can be used long-term for relapse prevention 1, 3.

Clinical Implementation Algorithm

1. Screen for alcohol withdrawal history (≥3 DSM-5 withdrawal criteria suggests high-symptom group) 3
2. If high withdrawal symptoms: Initiate gabapentin 300 mg TID, titrate to 600 mg TID over 1-2 weeks 1, 3
3. If low/no withdrawal symptoms: Consider alternative pharmacotherapy (baclofen, topiramate) as gabapentin unlikely to benefit 3
4. Monitor for dizziness, falls risk, and cognitive changes especially in first month 4
5. Assess renal function and adjust dose accordingly 2
6. Continue for 12-16 weeks minimum to assess full therapeutic response 1, 3