Donepezil

證據等級: L5

預測適應症: 10 個

Donepezil: From Alzheimer's Disease to Lingual-Facial-Buccal Dyskinesia

One-Sentence Summary

Donepezil is an acetylcholinesterase inhibitor (AChEI) widely used for Alzheimer's disease, where it enhances cholinergic neurotransmission by blocking the enzyme that breaks down acetylcholine. The TxGNN model generated 10 predicted new indications — all within the movement disorder and neurological disease space — with lingual-facial-buccal dyskinesia (a form of antipsychotic-induced tardive dyskinesia) emerging as the strongest candidate, supported by 0 registered clinical trials and 20 publications, including 2 Cochrane systematic reviews on cholinergic agents for tardive dyskinesia.

Quick Overview

Item	Content
Original Indication	Alzheimer's disease (dementia)
Predicted New Indication	Lingual-Facial-Buccal Dyskinesia (Primary Featured Candidate)
TxGNN Prediction Score	99.02%
Evidence Level	L3
Singapore Market Status	Not marketed
Number of Registrations	0
Recommended Decision	Proceed with Guardrails

Why Is This Prediction Reasonable?

Detailed mechanism of action data is not available in this Evidence Pack. Based on information drawn from the collected literature, Donepezil belongs to the acetylcholinesterase inhibitor (AChEI) drug class — it inhibits the AChE enzyme responsible for breaking down acetylcholine, thereby sustaining and amplifying cholinergic neurotransmission in the brain. This mechanism underlies its established efficacy in Alzheimer's disease, and it is mechanistically applicable to any condition involving cholinergic deficiency.

Lingual-facial-buccal dyskinesia is an orofacial subtype of tardive dyskinesia (TD) — an involuntary movement disorder arising from prolonged antipsychotic (neuroleptic) drug use. The dominant mechanistic hypothesis for TD involves a dual imbalance in the striatum: dopamine receptor supersensitivity combined with a relative cholinergic deficit. Restoring cholinergic tone with an AChEI could theoretically counterbalance excessive dopaminergic activity in the basal ganglia and suppress the involuntary movements that define this condition.

Two Cochrane systematic reviews (PMID 12137608, 2002; PMID 29553158, 2018) directly evaluated this hypothesis, reviewing randomised controlled trials of cholinergic agents for neuroleptic-induced TD. A 2004 systematic review and meta-analysis (PMID 15610922) specifically included donepezil and other AChEIs in this analysis. Taken together, these publications provide L3-level support for the drug class, and the mechanistic bridge from Donepezil's established cholinergic action to the cholinergic-deficiency component of TD pathophysiology is biologically coherent.

⚠️ Critical Safety Note: Case reports document that Donepezil can paradoxically induce movement abnormalities — including jaw tremor (PMID 18321753) and myoclonic status in combination with olanzapine (PMID 15965316). A pharmacovigilance study also identified AChEIs as a risk factor for Pisa syndrome (dystonia subtype) in the FDA FAERS database (PMID 24127392). This bidirectional risk profile must be built into any monitoring framework before clinical pursuit.

Clinical Trial Evidence

Currently no related clinical trials registered for Donepezil in lingual-facial-buccal dyskinesia or tardive dyskinesia.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
29553158	2018	Cochrane Systematic Review	Cochrane Database Syst Rev	Evaluated RCTs of cholinergic medication (including AChEIs) for antipsychotic-induced tardive dyskinesia; directly tested the cholinergic deficiency hypothesis
12137608	2002	Cochrane Systematic Review	Cochrane Database Syst Rev	Reviewed cholinergic drugs for neuroleptic-induced TD; established central cholinergic deficiency as a proposed component of TD pathogenesis
15610922	2004	Systematic Review / Meta-analysis	Prog Neuropsychopharmacol Biol Psychiatry	Meta-analysed RCTs of cholinergic agents (including donepezil, galantamine, rivastigmine) for neuroleptic-induced tardive dyskinesia — most directly relevant publication
19142126	2009	Clinical Observation	J Clin Psychopharmacology	Direct clinical study of donepezil's effect on tardive dyskinesia; most proximal evidence to the target indication
40791064	2025	Systematic Review	J Huntington's Disease	Systematic review of ChEIs and memantine for Huntington's disease cognitive symptoms — provides movement disorder context for AChEI use
15689723	2005	Case Report	J Am Acad Child Adolesc Psychiatry	Clinical case report of donepezil in tardive dyskinesia; early positive signal
24127392	2014	Pharmacovigilance Study	Pharmacotherapy	⚠️ FDA FAERS analysis: AChEIs (donepezil, rivastigmine, galantamine) associated with Pisa syndrome — movement disorder induction as adverse effect
18321753	2008	Case Report ⚠️	Parkinsonism Relat Disord	⚠️ Adverse event: Donepezil-induced jaw tremor — direct movement disorder induction risk signal
15965316	2005	Case Report ⚠️	Clin Neuropharmacology	⚠️ Adverse event: Myoclonic status in AD patient receiving donepezil + olanzapine — drug interaction and cholinergic risk
23917951	2013	Narrative Review	Drugs	Reviews non-dopaminergic (including cholinergic) approaches to motor control in Parkinson's disease; provides mechanistic context

Singapore Market Information

Donepezil is not currently registered in Singapore. No product licences are on record. Any clinical use or investigational study would require new drug application procedures with the Health Sciences Authority (HSA).

All Predicted Indications — Overview

The TxGNN model generated 10 predicted indications for Donepezil, all clustering within the movement disorder and neurological disease domain (prediction scores 98.3–99.2%). Lingual-facial-buccal dyskinesia ranks 8th by TxGNN score but first by evidence quality, illustrating that network proximity alone does not determine clinical actionability.

Rank	Predicted Indication	TxGNN Score	Evidence Level	Recommendation
1	Psychogenic movement disorders	99.23%	L5	Hold
2	Chronic tic disorder	99.19%	L4	Research Question
3	Primary orthostatic tremor	99.17%	L5	Hold
4	Extrapyramidal and movement disease	99.16%	L4	Research Question
5	Benign shuddering attacks	99.16%	L5	Hold
6	Tremor-nystagmus-duodenal ulcer syndrome	99.15%	L5	Hold
7	Benign paroxysmal tonic upgaze of childhood with ataxia	99.12%	L5	Hold
8	Lingual-facial-buccal dyskinesia	99.02%	L3	Proceed with Guardrails
9	Acute intermittent porphyria	98.75%	L5	Hold
10	Glaucoma	98.28%	L4	Research Question

Secondary Candidates Worth Watching

Rank 2 — Chronic Tic Disorder (L4, Research Question) Striatal cholinergic-dopaminergic imbalance is mechanistically implicated in tic disorders. An 18-week prospective open-label study in children with tics and ADHD showed initial positive signals (PMID 18343255). Animal models confirm that donepezil attenuates DOI-induced head twitches — a preclinical surrogate for tic behaviour in Tourette syndrome (PMID 14643839, 16045972). No RCTs exist; this remains a hypothesis-generating candidate requiring a controlled trial to progress.

Rank 4 — Extrapyramidal and Movement Disease (L4, Research Question) A case series reported beneficial effects in elderly patients with tardive dystonia and tremor (PMID 15669896). However, a 2025 systematic review (PMID 40224553) explicitly documents that AChEIs as a class can induce movement disorders as adverse events — a bidirectional risk that makes this broad indication high-risk without careful phenotype stratification. Requires subtype-specific analysis before any development decision.

Rank 10 — Glaucoma (L4, Research Question) A pilot study in normal-tension glaucoma (PMID 20415624) found donepezil improved optic nerve head blood flow and visual fields in patients with Alzheimer-pattern cerebral perfusion deficits. A clinical observation study (PMID 16503777) confirmed intraocular pressure reduction in newly diagnosed AD patients after 4 weeks of oral donepezil. Animal histology supports retinal neuroprotection against ischaemia-reperfusion injury (PMID 20197638). This is mechanistically credible — ACh acting on trabecular meshwork M3 receptors promotes aqueous outflow — but requires a dedicated glaucoma-focused trial. ⚠️ One case report documented angle-closure glaucoma upon donepezil discontinuation (PMID 16127117), signalling a cholinergic withdrawal effect that requires management guidance.

Safety Considerations

No local package insert data are available as Donepezil is not registered in Singapore. The following safety signals were identified from the collected evidence:

Paradoxical movement disorder induction: Donepezil can cause movement disorders — jaw tremor (PMID 18321753), Pisa syndrome/pleurothotonus (PMID 24127392), and myoclonic status in combination with olanzapine (PMID 15965316). This is the central safety paradox for any movement disorder repurposing effort.
Acute intermittent porphyria (Rank 9 — Hold): Enhanced cholinergic tone from AChEI use may trigger autonomic instability during AIP acute attacks. This predicted indication carries a potential harm signal and should not be pursued.
Glaucoma discontinuation effect: Abrupt withdrawal of donepezil has been associated with angle-closure glaucoma (PMID 16127117), suggesting rebound cholinergic effects on intraocular pressure require monitoring during dose tapering.

Please refer to the international Donepezil/Aricept Summary of Product Characteristics (SmPC) for comprehensive warnings, contraindications, and drug interaction data.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Two Cochrane systematic reviews and a dedicated meta-analysis of RCTs provide L3-level evidence that cholinergic agents can benefit neuroleptic-induced tardive dyskinesia — the disorder of which lingual-facial-buccal dyskinesia is a subtype. The cholinergic-dopaminergic rebalancing hypothesis is biologically coherent and directly connects Donepezil's established mechanism to this new indication. However, Donepezil's own documented capacity to induce movement disorders (jaw tremor, Pisa syndrome, myoclonus) creates a clinically important paradox that mandates structured safety monitoring as a precondition for any patient exposure.

To proceed, the following is needed:

MOA formalisation: Retrieve full Donepezil mechanism of action from DrugBank (DB00843) to document receptor targets and selectivity profile relevant to striatal cholinergic pathways
Safety data gap closure: Obtain the Singapore HSA package insert equivalent (Aricept SmPC or WHO drug information) for complete contraindication list, DDI profile, and population-specific warnings
Cochrane review deep-dive: Review the 2004 meta-analysis (PMID 15610922) to determine whether donepezil was individually evaluated, what effect size was observed, and what quality limitations affect conclusions
Indication boundary definition: Conduct a targeted subtype review to distinguish orobuccofacial/lingual-facial-buccal TD from other dyskinesia forms, confirming the mechanistic hypothesis applies specifically to this subtype
Prospective monitoring protocol design: Include baseline AIMS (Abnormal Involuntary Movement Scale) scoring, neurological assessment at each dose step, and pre-specified stopping rules if movement symptoms worsen
HSA registration pathway assessment: As Donepezil is not marketed in Singapore, evaluate whether a new drug application or clinical trial authorisation (CTA) pathway is applicable
Parallel development tracks: For Rank 2 (Chronic Tic Disorder) and Rank 10 (Glaucoma), design hypothesis-testing pilot studies given their mechanistic rationale and available preliminary data
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.