Gabapentin for Anxiety in Individuals with Substance Use History
Gabapentin can be safely used to treat anxiety in individuals with a history of substance use and may be preferable to benzodiazepines in this population due to its lower abuse potential and lack of controlled substance classification. 1, 2
Evidence for Efficacy in Anxiety
Gabapentin demonstrates effectiveness for anxiety symptoms, particularly in specific populations such as breast cancer survivors, with significant improvements observed at both 300 mg and 900 mg doses compared to placebo at 4 and 8 weeks. 2
The lower dose (300 mg) was associated with the best treatment outcomes for most patients except those with the highest baseline anxiety levels. 2
Systematic reviews support gabapentin's effectiveness in various forms of anxiety disorders, including preoperative anxiety, anxiety in breast cancer survivors, and social phobia, though it appears more effective as adjunctive therapy rather than monotherapy. 3
Safety Profile in Substance Use Populations
Gabapentin is not a scheduled controlled substance and does not exhibit affinity for benzodiazepine, opiate, or cannabinoid receptors, making it a safer alternative for patients with substance use history. 1
The FDA label notes that gabapentin misuse and abuse cases are rare and typically involve individuals with a history of poly-substance abuse taking higher-than-recommended doses for unapproved uses. 1
Gabapentin should be considered safe and appropriate for use in patients with all types of substance use disorders, including those taking opioid medications, as it is not especially harmful or lethal compared to other psychotropic drugs. 4
For patients reluctant to take controlled substances like benzodiazepines, or those with substance use history, gabapentin offers an alternative therapy without significant risk of addiction. 2
Advantages Over Benzodiazepines
Benzodiazepines carry significant risks in substance use populations, including increased risk of overdose when combined with opioids due to cumulative respiratory depression effects. 5
Gabapentinoids were initially believed to carry low dependence risk, though evidence now shows they can cause reinforcing euphoria, sedation, and dangerous respiratory depression when combined with opioids. 5
Gabapentin provides therapeutic benefit for both anxiety and comorbid conditions (such as hot flashes, neuropathic pain) at generic drug prices, offering a parsimonious treatment approach. 2
Important Caveats and Monitoring
Careful patient evaluation is essential: Screen for history of drug abuse and monitor for signs of gabapentin misuse (tolerance development, self-dose escalation, drug-seeking behavior). 1
Rare postmarketing reports describe withdrawal symptoms (agitation, disorientation, confusion) after abrupt discontinuation of higher-than-recommended doses, particularly in individuals with poly-substance abuse history. 1
Long-term prescribing concerns exist: Approximately 50% of patients prescribed gabapentinoids receive continuous treatment for at least 12 months, a practice of doubtful efficacy in many cases. 5
If discontinuation is planned, offer careful tapering and support to minimize withdrawal symptoms, as sudden cessation can lead to physical and psychological effects. 5
Clinical Application Algorithm
For anxiety in patients with substance use history:
Start with gabapentin 300 mg daily, particularly for mild-to-moderate anxiety. 2
Increase to 900 mg daily for patients with higher baseline anxiety if 300 mg is insufficient. 2
Monitor response at 4 weeks; therapeutic effects should be evident by this timepoint. 2
Avoid benzodiazepines in this population due to dependence risk and dangerous interactions with opioids. 5
Consider gabapentin particularly effective for alcohol dependence comorbid with anxiety, as it reduces cravings and improves abstinence rates. 3, 4