What is the initial dose of gabapentin (Neurontin) for sciatica?

Gabapentin Initial Dosing for Sciatica

The recommended initial dose of gabapentin for sciatica is 300 mg once daily, with gradual titration over weeks to an effective dose typically ranging from 900-3600 mg/day in divided doses. 1

Dosing Protocol

1. Starting Dose:

   • Begin with 300 mg once daily 1
   • This low starting dose helps minimize side effects during initiation

2. Titration Schedule:

   • Slow titration is recommended over weeks (unlike pregabalin which can be titrated over days)
   • Typical titration schedule:
     • Day 1: 300 mg once daily
     • Day 2: 300 mg twice daily
     • Day 3: 300 mg three times daily (900 mg/day) 2
     • Then increase by 300 mg increments every 1-2 weeks as needed and tolerated

3. Target Therapeutic Dose:

   • Effective dose range: 900-3600 mg/day
   • Most patients require at least 1800 mg/day for optimal efficacy 2
   • Administer in three divided doses (TID) due to gabapentin's pharmacokinetics

Dose Adjustments for Special Populations

• Renal Impairment: Dose adjustment required based on creatinine clearance 1:
  • CrCl ≥60 mL/min: 900-3600 mg/day (300-1200 mg TID)
  • CrCl 30-59 mL/min: 400-1400 mg/day (200-700 mg BID)
  • CrCl 15-29 mL/min: 200-700 mg/day (QD)
  • CrCl ≤15 mL/min: 100-300 mg/day (QD)

Efficacy Considerations

• While no large randomized controlled trials specifically address gabapentin for sciatica, case reports suggest efficacy 3
• Gabapentin has demonstrated efficacy in similar neuropathic pain conditions:
  • Postherpetic neuralgia: 32% of patients achieve at least 50% pain relief (vs 17% with placebo) 4
  • Diabetic neuropathy: 38% of patients achieve at least 50% pain relief (vs 21% with placebo) 4

Comparative Efficacy

• In patients with chronic sciatica, gabapentin showed superior pain reduction compared to pregabalin in a head-to-head trial 5
• Gabapentin requires slower titration and higher doses than pregabalin but has fewer and less severe adverse events in sciatica patients 5

Adverse Effects to Monitor

• Common side effects include:

  • Somnolence/sedation (14%)
  • Dizziness (19%)
  • Peripheral edema (7%)
  • Gait disturbance (14%) 4

• Approximately 11% of patients discontinue gabapentin due to side effects (vs 8.2% with placebo) 4

• Monitor for:

  • Depression or suicidal thoughts (rare but serious)
  • Enhanced sedation when combined with other CNS depressants
  • Increased fall risk, especially in elderly patients

Clinical Pearls

• Gabapentin should be taken with food to improve tolerability
• Evening dosing may be beneficial initially to minimize daytime sedation
• Abrupt discontinuation should be avoided; taper gradually over at least one week
• Full therapeutic effect may take several weeks to develop
• Consider early initiation in sciatica as gabapentin may help prevent central sensitization 3