Gabapentin Uses in Psychiatry
Gabapentin is primarily used in psychiatry for the treatment of anxiety disorders and as an adjunctive treatment for alcohol withdrawal and dependence, with limited evidence supporting its use for other psychiatric conditions.
Approved and Evidence-Based Uses
Neuropathic Pain (FDA-Approved)
- Gabapentin was originally designed as an anticonvulsant but is FDA-approved for neuropathic pain conditions 1
- Effective for diabetic peripheral neuropathy and postherpetic neuralgia at doses of 1800-3600 mg/day 2
- Typically initiated at 300 mg daily and gradually titrated up to effective doses 2
Anxiety Disorders (Off-Label)
- Moderate evidence supports gabapentin's efficacy in various anxiety disorders 3, 4
- Particularly effective for:
- Limited evidence for generalized anxiety disorder (GAD), with only case reports available 6
- Typical dosing for anxiety ranges from 300-3600 mg/day in divided doses 3
Alcohol Use Disorder (Off-Label)
- Effective for acute alcohol withdrawal syndrome of mild to moderate severity 4
- Reduces alcohol cravings and improves abstinence rates 3, 4
- Delays return to heavy drinking in alcohol-dependent individuals 4
- May be used as an alternative to benzodiazepines for alcohol withdrawal in appropriate patients 4
Limited or Insufficient Evidence Uses
Bipolar Disorder
- Limited evidence as an adjunctive treatment in bipolar disorder 3, 5
- Not recommended as monotherapy for bipolar disorder 5
- Insufficient evidence to support routine use in mood disorders 5
Insomnia
- Inconclusive evidence for insomnia treatment 5
- Not recommended as a first-line agent for sleep disorders 5
Other Substance Use Disorders
- Some limited evidence for opioid dependence treatment 3, 4
- Minimal evidence for cannabis dependence 4
- No significant benefit observed for cocaine or amphetamine abuse 4
Other Psychiatric Conditions
Dosing and Administration
- Starting dose: 300 mg at bedtime or 100-300 mg three times daily 2
- Gradual titration: Increase by 300 mg every 3-7 days as tolerated 2
- Therapeutic range: 1800-3600 mg/day in divided doses for most conditions 2
- Duration of adequate trial: 3-8 weeks for titration plus 2 weeks at maximum dose 2
Side Effects and Precautions
Common Side Effects
Serious Concerns
- Increased risk of suicidal thoughts and behavior (relative risk 1.8 compared to placebo) 1
- Risk of dependence and withdrawal symptoms with long-term use 2
- Approximately 50% of patients prescribed gabapentin in England had been treated continuously for at least 12 months, which is not recommended by clinical guidelines 2
Special Populations
- Requires dose adjustment in renal impairment 2
- In pediatric patients (3-12 years), increased risk of emotional lability (6%), hostility (5.2%), hyperkinesia (4.7%), and thought disorder (1.7%) 1
Clinical Pearls
- Gabapentin has nonlinear pharmacokinetics due to saturable absorption, requiring careful titration 2
- When discontinuing, gradual tapering is necessary to prevent withdrawal symptoms 2
- Consider combination therapy with medications having different mechanisms (e.g., pregabalin and duloxetine) for refractory neuropathic pain 8
- For anxiety disorders, gabapentin may be particularly useful in patients who cannot tolerate or have contraindications to first-line treatments 4
- Monitor for misuse potential, especially in patients with history of substance use disorders 2
Alternative Treatments to Consider
- For neuropathic pain: Pregabalin, duloxetine, amitriptyline 8
- For anxiety: SSRIs, SNRIs, buspirone 4
- For alcohol withdrawal: Benzodiazepines (first-line), carbamazepine 4
Gabapentin should be prescribed with clear therapeutic goals and regular monitoring of efficacy and side effects. If no benefit is observed after an adequate trial, consider tapering and discontinuing rather than continuing indefinitely.