Importance of gabapentin dose in treatment of opioid withdrawal

J Clin Psychopharmacol. 2011 Oct;31(5):593-6. doi: 10.1097/JCP.0b013e31822bb378.


Aim: The aim of the study was to evaluate the efficacy of gabapentin (1600 mg/d) as an adjunctive to methadone-assisted detoxification in the treatment of opioid withdrawal symptoms.

Design: This was a 3-week open-label study (as second phase) following a double-blind, placebo-controlled study with 900 mg/d of gabapentin (as first phase of this study).

Setting: The study was conducted at a specialized outpatient clinic for the treatment of patients with addictive disorders.

Participants: The study subjects were composed of 27 patients addicted to opiate who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for opioid dependency, randomly selected among outpatients referred to our clinic.

Intervention: Subjects received adjunctive treatment with gabapentin (1600 mg/d) in addition to methadone-assisted detoxification for 3 weeks.

Measurements: Subjective Opiate Withdrawal Scale (SOWS) with a total score of 0 to 64 was administered at 6 time points during the study.

Findings: The total SOWS score was significantly decreased after the intervention. Compared to our previous trial, an almost significant difference was observed in total SOWS scores between groups treated with gabapentin 1600 and 900 mg/d at the end of the intervention period (P = 0.06). Gabapentin with a dose of 1600 mg/d was significantly superior to a dose of 900 mg/d in decreasing severity of coldness, diarrhea, dysphoria, yawing, and muscle tension.

Conclusions: Add-on gabapentin with a dose of 1600 mg/d is effective in reducing some of the withdrawal symptoms in patients addicted to opiate undergoing methadone-assisted detoxification.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amines / administration & dosage
  • Amines / therapeutic use*
  • Analgesics, Opioid / therapeutic use
  • Anticonvulsants / administration & dosage
  • Anticonvulsants / therapeutic use
  • Cyclohexanecarboxylic Acids / administration & dosage
  • Cyclohexanecarboxylic Acids / therapeutic use*
  • Dose-Response Relationship, Drug
  • Female
  • Gabapentin
  • Humans
  • Male
  • Methadone / therapeutic use
  • Middle Aged
  • Opiate Substitution Treatment / methods
  • Opioid-Related Disorders / rehabilitation*
  • Severity of Illness Index
  • Substance Withdrawal Syndrome / drug therapy*
  • Substance Withdrawal Syndrome / physiopathology
  • Treatment Outcome
  • Young Adult
  • gamma-Aminobutyric Acid / administration & dosage
  • gamma-Aminobutyric Acid / therapeutic use*


  • Amines
  • Analgesics, Opioid
  • Anticonvulsants
  • Cyclohexanecarboxylic Acids
  • gamma-Aminobutyric Acid
  • Gabapentin
  • Methadone