What is the typical starting dose of gabapentin (Neurontin) for adults?

Gabapentin Starting Dose for Adults

The recommended starting dose of gabapentin for adults is 100-300 mg at bedtime or 100-300 mg three times daily, with gradual titration based on response and tolerability. 1, 2

Initial Dosing Strategy

• Starting dose options:

  • 100-300 mg at bedtime (preferred for minimizing daytime sedation) 1
  • 100-300 mg three times daily 1, 3
  • For postherpetic neuralgia: Day 1: 300 mg once; Day 2: 300 mg twice daily; Day 3: 300 mg three times daily 2

• Titration schedule:

  • Increase by 100-300 mg every 1-7 days as tolerated 1
  • Allow 3-8 weeks for complete titration plus 2 weeks at maximum dose to assess efficacy 1

Maximum Dosing

• Maximum effective dose: 3600 mg/day in 3 divided doses 1, 2
• Typical effective dose range: 1800-3600 mg/day 1, 4
• For unexplained chronic cough: Maximum tolerable daily dose of 1800 mg in two divided doses 1

Dosage Adjustment for Special Populations

• Renal impairment: Dose adjustment required based on creatinine clearance 2:

  Creatinine Clearance (mL/min)	Total Daily Dose Range (mg/day)
  ≥60	900-3600
  30-59	400-1400
  15-29	200-700
  <15	100-300

• Elderly patients: Lower starting doses and slower titration recommended due to potential for decreased renal function 1, 3, 2

Pharmacokinetic Considerations

• Gabapentin has nonlinear pharmacokinetics due to saturable absorption, making careful titration necessary 1
• The maximum time between doses should not exceed 12 hours to maintain therapeutic levels 2

Side Effects and Monitoring

• Most common side effects include dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%) 5
• Side effects are typically mild to moderate and often subside within approximately 10 days of treatment initiation 4
• Adverse events are more common with gabapentin (63%) than with placebo (49%) 5
• Adverse event withdrawals occur in approximately 11% of patients 5

Clinical Pearls

• Starting at lower doses with gradual titration helps minimize side effects while establishing efficacy
• Doses of 1800 mg/day or higher are often needed for optimal pain relief 4, 5
• An adequate trial of gabapentin may require 2 months or more to determine effectiveness 1
• For neuropathic pain conditions, approximately 3-4 out of 10 patients achieve at least 50% pain relief with gabapentin 5

The low starting dose with gradual titration approach balances the need to minimize side effects while working toward an effective therapeutic dose. This approach is supported by multiple guidelines and the FDA label for gabapentin.