Gabapentin Treatment of Benzodiazepine Dependence

Benzodiazepine dependence is a growing public health problem for which very few evidenced-based treatment approaches are available. Approximately 683,000 individuals met past year criteria for sedative-hypnotic use disorders in the US during 2010, a prevalence greater than heroin or methamphetamine dependence. The most commonly prescribed sedative-hypnotic agents are the benzodiazepines. Chronic use induces pharmacodynamic tolerance in the GABA neurotransmitter system and individuals with physiological dependence find benzodiazepines difficult to discontinue because of withdrawal or rebound symptoms, which include autonomic arousal, depression, anxiety, and insomnia. Available evidence-based treatment approaches have been primarily directed at therapeutic users of benzodiazepines who do not meet criteria for a substance use disorder, with a general consensus that the gradual taper of benzodiazepines over a period of several months is the optimal approach. However, patients with benzodiazepine dependence are typically referred for inpatient detoxification treatment, which rapidly tapers patients off benzodiazepines. Protracted withdrawal symptoms frequently persist after discharge, predisposing patients to relapse. More effective pharmacotherapeutic strategies are needed for the treatment of benzodiazepine dependence in the outpatient setting.

Gabapentin has proven to be a safe and well-tolerated medication with a low abuse liability, thereby making it ideal for use in the outpatient setting.

The proposed Exploratory Development research project is a double-blind randomized controlled clinical trial comparing the efficacy of gabapentin to placebo for the outpatient treatment of benzodiazepine dependence. The goal of this project is to study the effects of gabapentin on the participants' benzodiazepine use in a facilitated taper-to-abstinence model, where participants will be actively using benzodiazepines at study entry, gabapentin treatment will be introduced, and participants will be counseled to gradually discontinue benzodiazepine use over the study period while gabapentin treatment is maintained. A modified version of Medical Management will be used to facilitate compliance with study medication and other study procedures, and includes clinical instruction for gradually reducing benzodiazepine use 25% per week. Benzodiazepines are not prescribed in the proposed study; participants continue to obtain benzodiazepines from their own prescribed or nonprescribed sources.

Eligibility Criteria:
Inclusion Criteria:

1. Meets DSM-IV-TR criteria for BZD dependence
2. Using BZDs a minimum of 5 days per week over the past 28 days
3. Between the ages of 18 and 60
4. Able to provide informed consent

Exclusion Criteria:

1. Any current DSM-IV-TR Axis I psychiatric disorder, other than BZD dependence, that might require intervention over the course of the study, including schizophrenia, bipolar disorder, major depressive disorder or panic disorder.
2. Receiving psychotropic medication other than BZDs
3. Evidence of physiological BZD withdrawal (pulse \> 100; blood pressure \> 140/90)
4. History of BZD withdrawal seizures or withdrawal delirium
5. History of allergic reaction to GBP
6. Pregnancy, lactation, or failure in female patients to use adequate contraceptive methods
7. Unstable physical disorders which might make participation hazardous medical history
8. Subjects who have a current DSM-IV-TR diagnosis of other substance dependence, with the exception of nicotine and caffeine history; dependence