What is the starting dose of Gabapentin (Neurontin)?

From the Guidelines

The starting dose of gabapentin should be 100-300 mg at bedtime or 100-300 mg three times daily. This recommendation is based on the most recent and highest quality study available, which provides guidelines for the pharmacological management of neuropathic pain 1. The study suggests that the dose can be increased by 100-300 mg every 1-7 days as tolerated, with a reduction in dose if there is impaired renal function.

Key Considerations

• The dose titration should be done gradually to minimize side effects, which are often dose-related.
• For geriatric patients or those with renal impairment, a lower starting dose of 100 mg daily may be appropriate, with slower titration.
• Gabapentin should be taken with food to improve absorption and reduce gastrointestinal side effects.
• Patients should be advised not to stop gabapentin abruptly, as this can lead to withdrawal symptoms, and any discontinuation should be gradual over at least one week.

Important Details

• The efficacy and tolerability of gabapentin can vary among patients, and the medication may require 2 months or more for an adequate trial.
• The maximum dosage of gabapentin is not strictly defined but is typically reached when pain relief is achieved, dose-limiting adverse effects occur, or a dose of 3600 mg/d in 3 divided doses is reached.
• Gabapentin works by binding to calcium channels in the nervous system, modulating the release of excitatory neurotransmitters, and reducing neuronal excitability, which explains its effectiveness for neuropathic pain.

From the FDA Drug Label

In adults with postherpetic neuralgia, gabapentin may be initiated on Day 1 as a single 300 mg dose, on Day 2 as 600 mg/day (300 mg two times a day), and on Day 3 as 900 mg/day (300 mg three times a day). The starting dose is 300 mg three times a day. The starting dose range is 10 mg/kg/day to 15 mg/kg/day, given in three divided doses

The starting dose of gabapentin is:

• 300 mg on Day 1 for postherpetic neuralgia in adults
• 300 mg three times a day for epilepsy with partial onset seizures in patients 12 years of age and above
• 10 mg/kg/day to 15 mg/kg/day, given in three divided doses, for pediatric patients age 3 to 11 years 2

From the Research

Gabapentin Starting Dose

• The starting dose of gabapentin is not explicitly stated in the provided studies, but the dose can be inferred based on the context of each study.
• In the study 3, higher-dose gabapentinoids were defined as gabapentin >300 mg/d or pregabalin >75 mg/d, while lower-dose gabapentinoids were defined as gabapentin ≤300 mg/d or pregabalin ≤75 mg/d.
• This suggests that a starting dose of gabapentin ≤300 mg/d may be considered a lower dose, while a starting dose of gabapentin >300 mg/d may be considered a higher dose.
• However, it is essential to note that the appropriate starting dose of gabapentin may vary depending on the individual patient's kidney function, as patients with decreased kidney function may be at an increased risk of adverse effects 4, 3.

Kidney Function and Gabapentin Dose

• The study 4 found that patients with a creatinine clearance (CrCl) <60 mL/min were frequently prescribed inappropriately high doses of gabapentinoids.
• The study 3 also found that starting a gabapentinoid at a higher dose was associated with a slightly higher risk of adverse events in older adults with chronic kidney disease (CKD).
• These findings suggest that kidney function should be taken into account when determining the starting dose of gabapentin, and that lower doses may be more appropriate for patients with decreased kidney function.

Comparison with Pregabalin

• The study 5 compared the efficacy and safety of pregabalin and gabapentin in patients with chronic kidney injury undergoing haemodialysis.
• The study found that pregabalin was more efficacious than gabapentin in reducing pruritus, but that patients who took gabapentin experienced significantly fewer side effects than those who took pregabalin.
• This suggests that the choice between gabapentin and pregabalin may depend on the individual patient's needs and medical history, and that the starting dose of either medication should be carefully considered to minimize the risk of adverse effects.