Baclofen

證據等級: L5

預測適應症: 2 個

Baclofen: From Spasticity to Attention Deficit-Hyperactivity Disorder

One-Sentence Summary

Baclofen is a GABA-B receptor agonist classically used for the treatment of spasticity in neurological conditions. The TxGNN model predicts it may be effective for Attention Deficit-Hyperactivity Disorder (ADHD) (Rank #1; score: 99.32%), with 0 clinical trials and 10 publications providing only indirect mechanistic support; and secondarily for Nicotine Dependence (Rank #2; score: 99.19%), which carries stronger evidence with 3 Phase 2 clinical trials and 20 publications. These two predictions differ substantially in evidence maturity and should be evaluated independently.

Quick Overview

Item	Content
Original Indication	Spasticity (Baclofen not registered in the Philippines)
Predicted New Indication	Attention Deficit-Hyperactivity Disorder (ADHD)
TxGNN Prediction Score	99.32%
Evidence Level	L4 (Preclinical / mechanistic studies only)
Philippines Market Status	✗ Not Marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available from this evidence pack. Based on established pharmacological knowledge, Baclofen is a selective GABA-B receptor agonist. It acts on pre- and post-synaptic GABA-B receptors in the central nervous system, suppressing neuronal excitability and inhibiting the release of excitatory neurotransmitters — including dopamine — particularly within the mesolimbic pathways.

The theoretical connection to ADHD rests on Baclofen’s ability to dampen excessive dopaminergic tone in the ventral tegmental area (VTA) and modulate frontal-striatal circuits that govern attention, impulse control, and executive function — pathways consistently implicated in ADHD pathophysiology. The repurposing rationale from this evidence pack describes this as “highly speculative” with no direct neuroimaging or pharmacological human studies yet supporting it. Critically, conventional ADHD treatments (stimulants such as methylphenidate) work by enhancing dopaminergic and noradrenergic signalling, which is mechanistically the opposite of what Baclofen does; this raises a flag about potential worsening of attentional symptoms.

The most concrete indirect evidence comes from Baclofen’s documented use in Tourette Syndrome — a neurodevelopmental disorder with up to 60% ADHD comorbidity — where baclofen has been used for tic suppression. The TxGNN knowledge graph model likely captured these shared neurodevelopmental substrates when generating this prediction, rather than direct pharmacological evidence for ADHD per se.

Clinical Trial Evidence

Currently no related clinical trials are registered for Baclofen in ADHD.

Literature Evidence (ADHD)

PMID	Year	Type	Journal	Key Findings
35345730	2022	Systematic Review	Cureus	Reviews behavioural interventions, antipsychotics, and alpha agonists for tics in Tourette’s; ADHD is a primary comorbidity; no direct Baclofen-ADHD assessment
26366961	2015	Review	Clin Neuropharmacology	Mood stabilisers in paediatric autism spectrum disorders with ADHD-like behavioural problems; contextual background for neurodevelopmental pharmacotherapy
24295630	2013	Review	Int Rev Neurobiology	Emerging Tourette treatments including pipeline agents; ADHD comorbidity management reviewed; highlights unmet clinical need
10342599	1999	Review	J Child Neurology	450 Tourette patients treated with baclofen and botulinum toxin; baclofen used in a ADHD-comorbid population; only indirect evidence for Baclofen-ADHD
21300040	2011	Animal Study	Brain Research	EEG responses to GABA-B agonists (including baclofen) in spontaneously hypertensive rat (SHR) ADHD model; provides mechanistic background for GABAergic modulation in ADHD-like circuits
24062084	2014	Animal Study	Psychopharmacology	Guanfacine (α2A agonist) reduces impulsive decision-making via ventral hippocampus; contextually relevant — highlights GABAergic vs. noradrenergic approaches to impulsivity
24496320	2014	Animal Study	Neuropsychopharmacology	Anterior cingulate cortex and basolateral amygdala contributions to effortful decision-making deficits in ADHD-like models; no direct Baclofen testing
24103016	2013	Animal Study	Eur J Neuroscience	Habenula regulates monoaminergic neurotransmission and social play in rats; mechanistic background for GABAergic modulation of reward and attention circuits
11393328	2001	Review	Paediatric Drugs	Tourette syndrome management; clonidine as first-line agent; Baclofen listed as a used option for tic suppression in patients with ADHD comorbidity
30122296	2019	Review	L’Encephale	Off-label methylphenidate use in adult ADHD; highlights the persistent gap in approved treatments and the practice of framed off-label prescribing

Additional Predicted Indication: Nicotine Dependence (Rank #2)

This second prediction carries substantially stronger evidence than ADHD and is presented here for completeness. TxGNN score: 99.19% Evidence Level: L2 Decision Stage: Research Question

Mechanistic rationale: Baclofen acts on GABA-B receptors in the VTA to inhibit dopamine neuron firing, thereby attenuating the nicotine-induced surge in mesolimbic dopamine — the core neurobiological reward signal driving nicotine addiction. This mechanism has been directly demonstrated in multiple animal studies and parallels Baclofen’s evidence base in alcohol use disorder (AUD), where it is approved in France. The GABAergic reward-attenuation mechanism appears transdiagnostic across substance use disorders.

Clinical Trial Evidence (Nicotine Dependence)

Trial Number	Phase	Status	Enrollment	Key Findings
NCT01821560	Phase 2	Completed	44	Used perfusion fMRI to examine Baclofen’s effects on brain and behavioural responses to smoking cues in cigarette smokers; only completed trial — highest direct relevance for efficacy signals
NCT00257894	Phase 2	Terminated	41	Assessed Baclofen’s effect on smoking urge, withdrawal, and reinforcement in moderate-to-heavy smokers; terminated after 41 enrolments (reason unreported); safety and preliminary data may be available
NCT01228994	Phase 2	Terminated	6	Tested the GABAergic hypothesis of nicotine dependence; terminated very early (only 6 subjects), limiting statistical validity; conceptual proof-of-concept value only

Literature Evidence (Nicotine Dependence)

PMID	Year	Type	Journal	Key Findings
24553576	2014	Animal Study	Psychopharmacology	Baclofen attenuates nicotine rewarding properties and withdrawal manifestations in rodents; supports direct pharmacological mechanism
18682277	2008	Animal Study	Neuroscience Letters	Baclofen (3 mg/kg) reduces nicotine-induced conditioned place preference and discriminative effects in rats; provides dose-effect data for mechanistic understanding
19250803	2009	Animal Study	Eur Neuropsychopharmacology	Baclofen prevents drug-induced reinstatement of nicotine-seeking behaviour and nicotine place preference in rodents; directly relevant relapse prevention data
23500668	2013	Animal Study	Prog Neuropsychopharmacol Biol Psychiatry	Baclofen prevents mecamylamine-precipitated nicotine withdrawal; α4β2 nicotinic receptor density modulated; elucidates receptor-level withdrawal mechanism
25868070	2015	Conference Abstract (Pilot RCT)	Neuropsychopharmacology	Baclofen as pharmacotherapy for concurrent alcohol and nicotine dependence; double-blind, placebo-controlled randomised pilot; dual substance use design
24971600	2015	Review	Neuropharmacology	GABA-B receptors as therapeutic targets for substance use disorders; positive allosteric modulators discussed; comprehensive preclinical evidence summary
29250815	2018	Review	Pharmacotherapy	Current and emerging pharmacotherapies for tobacco cessation; Baclofen discussed in context of GABAergic approaches; NRT limitations highlighted
17338593	2007	Review	CNS Drugs	Pharmacotherapy of dual substance abuse (alcohol + nicotine); single-drug therapies reviewed; Baclofen relevant for co-occurring dependence
38555115	2024	Review (Drug Repurposing)	Int Rev Neurobiology	Repurposing drugs for alcohol use disorder; Baclofen listed among approved AUD medications in France; shared GABAergic mechanism with nicotine reinforcement suppression
28919445	2018	Review	Prog Neuropsychopharmacol Biol Psychiatry	Cognitive effects of addictolytic medications including Baclofen; relevant for assessing cognitive risk-benefit profile in nicotine cessation treatment

Philippines Market Information

Baclofen is not currently registered in the Philippines. There are no active licenses on record with the Food and Drug Administration of the Philippines (FDA Philippines).

Note for decision-makers: Before any clinical or research use in the Philippines, a product registration application would be required. Baclofen is available as a generic in many international markets (oral tablets 10 mg, 25 mg; intrathecal formulation). Its regulatory status in other jurisdictions (e.g., EMA-approved in the EU for spasticity; approved in France for alcohol use disorder under specific conditions) could support a bridging application strategy.

Safety Considerations

No key warnings, contraindications, or drug interaction data are available in this evidence pack for the Philippines market.

Please refer to the package insert and approved prescribing information from reference regulatory agencies (EMA, US FDA) for safety information. Known class-level concerns with Baclofen include: CNS depression, sedation, respiratory depression at high doses, abrupt withdrawal syndrome (potentially fatal — gradual dose tapering required), and particular caution in renal impairment (primary renal excretion).

Conclusion and Next Steps

Primary Prediction — ADHD

Decision: Hold

Rationale: The ADHD prediction is mechanistically speculative and rests entirely on indirect evidence from Tourette syndrome and animal circuit models. No clinical trials have tested Baclofen directly for ADHD, and the direction of pharmacological action (dopamine suppression) is theoretically inconsistent with established ADHD treatment principles (dopamine/noradrenaline enhancement). The TxGNN model likely detected shared neurodevelopmental signatures rather than direct therapeutic applicability.

To proceed, the following is needed:

A dedicated mechanistic hypothesis paper or preclinical study directly testing Baclofen in validated ADHD animal models (e.g., SHR rats, dopamine transporter knock-down models)
Neuroimaging or pharmacodynamic data in human subjects with ADHD assessing GABAergic modulation of prefrontal circuits
Safety profile review specifically addressing whether GABA-B agonism worsens attentional performance

Secondary Prediction — Nicotine Dependence

Decision: Proceed with Guardrails

Rationale: Nicotine dependence has a clear and well-supported mechanistic rationale (GABA-B–mediated attenuation of mesolimbic dopamine reward), confirmed preclinical data across multiple animal paradigms, and one completed Phase 2 clinical trial (NCT01821560, n=44). The two terminated trials reflect feasibility and recruitment challenges rather than safety signals. This prediction is further supported by Baclofen’s approved use in alcohol use disorder in France, pointing to a transdiagnostic GABAergic mechanism across addictive disorders.