What is the recommended dosage of gabapentin (Neurontin) for an adult patient with anxiety?

Gabapentin Dosing for Anxiety in Adults

For anxiety symptoms in adults, start gabapentin at 300 mg once daily and maintain this dose, as higher doses (900 mg/day) do not provide additional benefit and increase side effects. 1

Evidence-Based Dosing Protocol

The strongest and most recent evidence specifically for anxiety comes from a randomized, double-blind, placebo-controlled trial in breast cancer survivors that directly compared 300 mg versus 900 mg versus placebo. 1 This study provides critical dosing guidance:

• Start at 300 mg once daily - this dose demonstrated significant anxiolytic effects at 4 weeks (p=0.005) compared to placebo 1
• The 300 mg dose was associated with the best treatment outcomes for all patients except those with the highest baseline anxiety 1
• Anxiolytic effects persisted at 8 weeks, confirming sustained benefit 1
• The magnitude of improvement was proportional to baseline anxiety severity 1

Dosing for Severe Anxiety

For patients with more severe anxiety symptoms:

• Consider 600-800 mg daily in divided doses for those with the highest baseline anxiety 1, 2
• One study showed 800 mg attenuated anxiety in simulated public speaking tests 2
• For panic disorder specifically, flexible dosing between 600-3600 mg/day showed benefit only in severely ill patients (Panic and Agoraphobia Scale score ≥20) 3

Titration Strategy

Unlike neuropathic pain management, anxiety treatment does not require aggressive titration:

• Begin with 300 mg once daily - no need for the gradual escalation used in pain management 1
• Assess response at 4 weeks before considering dose increases 1
• If inadequate response and high baseline anxiety, may increase to 600-900 mg/day in divided doses 1, 3

Critical Clinical Pearls

• Lower doses are more effective for anxiety than for pain - the 300 mg dose that works for anxiety is far below the 1800-3600 mg/day typically needed for neuropathic pain 4, 1
• Gabapentin offers advantages over benzodiazepines: no addiction risk, no controlled substance status, and can treat comorbid hot flashes in cancer survivors 1
• Patients with substance use history may particularly benefit from gabapentin as an alternative to benzodiazepines 1

Common Side Effects

• Somnolence, dizziness, and headache are the most common adverse effects 3, 2
• These effects are generally mild at the 300 mg dose used for anxiety 1
• Side effects are dose-dependent, providing another reason to start and potentially maintain at 300 mg 3

Important Caveats

• The evidence base for gabapentin in anxiety is limited - most studies are small and in specific populations (breast cancer survivors, panic disorder, simulated anxiety) 1, 3, 2
• Gabapentin is not FDA-approved for anxiety - this is off-label use 1
• For elderly or renally impaired patients, start at lower doses (100-200 mg/day) and adjust based on creatinine clearance 4
• Do not abruptly discontinue - taper gradually over at least 1 week to avoid withdrawal symptoms 4