Baclofen
| 證據等級: L5 | 預測適應症: 2 個 |
目錄
Baclofen: From Spasticity to Attention Deficit-Hyperactivity Disorder
One-Sentence Summary
Baclofen is a selective GABA-B receptor agonist primarily used to treat spasticity and muscle rigidity associated with neurological conditions such as multiple sclerosis and spinal cord injury. The TxGNN model predicts it may be effective for Attention Deficit-Hyperactivity Disorder (ADHD), currently supported by 0 clinical trials and 10 publications, predominantly at preclinical or indirect evidence levels. A second predicted indication — nicotine dependence — carries substantially stronger clinical support (3 trials, 20 publications) and may represent the more actionable near-term repurposing opportunity.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Spasticity (no New Zealand regulatory record on file) |
| Predicted New Indication | Attention Deficit-Hyperactivity Disorder (ADHD) |
| TxGNN Prediction Score | 99.32% |
| Evidence Level | L4 |
| New Zealand Market Status | Not Marketed |
| Number of Authorizations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Baclofen is a selective GABA-B receptor agonist that inhibits neuronal excitability by activating both presynaptic and postsynaptic GABA-B receptors across the spinal cord and brain. Activation of presynaptic GABA-B receptors reduces the release of excitatory neurotransmitters — including glutamate and monoamines such as dopamine and noradrenaline. This inhibitory modulation of monoaminergic tone forms the theoretical bridge between Baclofen's established use in spasticity and its proposed application in ADHD.
ADHD is characterised by dysregulation of dopaminergic and noradrenergic signalling in the prefrontal cortex and fronto-striatal circuits. Baclofen's GABA-B agonism could theoretically dampen the excessive or erratic firing of these pathways, improving sustained attention, impulse control, and executive function. Indirect mechanistic support comes from studies using spontaneously hypertensive rats (SHR) — a validated preclinical ADHD model — in which GABA-B receptor stimulation modulated cortical EEG oscillations in ways consistent with normalising attention-related neural activity.
However, the available human literature where Baclofen appears in ADHD-adjacent contexts relates primarily to comorbid conditions such as Tourette syndrome and autism spectrum disorders, where ADHD symptoms are secondary targets rather than the primary endpoint. A direct, prospectively tested mechanistic link between GABA-B agonism and ADHD core symptoms — inattention, hyperactivity, and impulsivity — has not yet been established in clinical trials.
Clinical Trial Evidence
Currently no related clinical trials registered for Baclofen in ADHD.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 35345730 | 2022 | Systematic Review / Meta-analysis | Cureus | Reviews behavioural interventions, antipsychotics, and alpha-agonists for tics in Tourette's syndrome; ADHD is a major comorbidity addressed indirectly, supporting shared dopaminergic/GABAergic targets |
| 30122296 | 2019 | Observational / Clinical | L'Encéphale | Documents supervised off-label methylphenidate prescribing in adult ADHD; highlights pharmacotherapy gaps that Baclofen might theoretically address |
| 26366961 | 2015 | Review | Clinical Neuropharmacology | Reviews mood stabilisers in children and adolescents with ASD; attention deficits are highlighted as a cross-diagnostic pharmacotherapy target shared with ADHD |
| 24295630 | 2013 | Review | International Review of Neurobiology | Reviews emerging treatments for Tourette syndrome including Baclofen; ADHD comorbidity treated as a secondary target within the same neurobiological framework |
| 10342599 | 1999 | Review | Journal of Child Neurology | 450 patients with tics/Tourette's treated with Baclofen and botulinum toxin; earliest substantial clinical exposure dataset for Baclofen in ADHD-comorbid neurological conditions |
| 21300040 | 2011 | Animal / Preclinical | Brain Research | EEG responses to neurotransmitter agonists in SHR rats (ADHD model) vs. controls; GABA-B agonism modulates frontal cortex and hippocampal EEG in attention-relevant patterns |
| 24062084 | 2014 | Animal / Preclinical | Psychopharmacology | α2A-adrenergic stimulation in ventral hippocampus reduces impulsive decision-making; mechanistically parallel to GABA-B modulation strategies in ADHD |
| 11393328 | 2001 | Review | Paediatric Drugs | Comprehensive review of Tourette syndrome management; contextualises noradrenergic and dopaminergic circuits as shared therapeutic targets with ADHD |
| 24103016 | 2013 | Animal / Preclinical | European Journal of Neuroscience | Habenula integrity required for social play in rats; habenula regulates monoaminergic tone relevant to ADHD reward and motivation circuitry |
| 24496320 | 2014 | Animal / Preclinical | Neuropsychopharmacology | Anterior cingulate cortex and basolateral amygdala contributions to cognitive effort-based decision-making; deficits in this domain are characteristic of ADHD and depression |
New Zealand Market Information
Baclofen is not currently authorised or marketed in New Zealand. No product licences are on record.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence base for Baclofen in ADHD remains entirely at the preclinical and indirect level (L4). With no registered clinical trials specifically targeting ADHD, and a literature base that addresses ADHD only as a comorbidity in Tourette syndrome or autism spectrum disorder contexts, there is insufficient human clinical data to support advancing to a formal repurposing evaluation at this time.
To proceed, the following is needed:
- At least one Phase 1/2 clinical trial directly investigating Baclofen in ADHD patients (symptom reduction as primary endpoint)
- Formal MOA documentation confirming GABA-B receptor modulation of prefrontal dopaminergic and noradrenergic circuits in ADHD-relevant concentrations
- Safety profile, contraindications, and drug interaction data for the New Zealand regulatory context
- Differentiation study separating Baclofen's effects on ADHD core symptoms from its effects on comorbid tic or anxiety disorders
⚑ Secondary Prediction to Note — Nicotine Dependence (L2, Recommended: Research Question)
The TxGNN model also predicts Baclofen as a candidate for nicotine dependence (score: 99.19%), and this indication carries significantly stronger evidence. Three Phase 2 clinical trials were identified, including one completed trial (NCT01821560, n=44) examining Baclofen's effects on brain activity and smoking behaviour in cigarette smokers. Twenty publications are on record, spanning animal mechanistic studies, a randomised conference trial, and multiple pharmacotherapy reviews.
The mechanistic rationale is well-characterised: Baclofen suppresses dopamine release in the nucleus accumbens by activating presynaptic GABA-B receptors at the ventral tegmental area (VTA), directly attenuating nicotine's reinforcing effects in the mesolimbic reward circuit. This pathway is essentially the same mechanism by which Baclofen has demonstrated efficacy in alcohol use disorder — itself an approved indication in France and several European countries.
This indication warrants a dedicated report and should be escalated to decision stage S2. It represents a more mature repurposing case with translatable mechanism, completed human pilot data, and a clear analogy to an already-approved use.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.