Atropine

證據等級: L5

預測適應症: 10 個

Atropine: From Anticholinergic Indications to Migraine Disorder

One-Sentence Summary

Atropine is a classical muscarinic receptor antagonist with established clinical uses including symptomatic bradycardia, organophosphate antidote, pre-operative medication, and pediatric myopia control. The TxGNN model predicts it may be effective for Migraine Disorder as its highest-ranked novel indication, with 0 clinical trials and 13 publications currently supporting this direction — predominantly animal and mechanistic studies.

Note: A higher-evidence application exists within the headache category: for post-dural puncture headache (PDPH), the neostigmine+atropine combination is supported by 2 completed RCTs and reaches evidence level L2. See the Conclusion section for details.

Quick Overview

Item	Content
Original Indication	Bradycardia; organophosphate poisoning antidote; pre-operative anticholinergic; pediatric myopia control (topical)
Predicted New Indication	Migraine Disorder
TxGNN Prediction Score	99.56%
Evidence Level	L4 (preclinical and mechanistic studies only)
Singapore Market Status	Not Marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Atropine is a competitive antagonist at muscarinic (M-type) acetylcholine receptors, blocking parasympathetic outflow to smooth muscle, exocrine glands, and the central nervous system. Detailed MOA data is not available from the regulatory dataset; based on established pharmacology, atropine's primary action is competitive inhibition of muscarinic receptor subtypes (M1–M5), which underpins its use in bradycardia reversal, antisecretory premedication, and cycloplegia.

The cholinergic system plays a documented modulatory role in migraine pathophysiology. Parasympathetic activation through the sphenopalatine ganglion pathway promotes dural vasodilation and plasma protein extravasation — hallmarks of neurogenic inflammation in migraine (PMID 9344563). In animal models, the central cholinergic system also contributes to the antinociceptive effect of the anti-migraine drug sumatriptan (PMID 8930196). More recently, meningeal mast cell–mediated cholinergic modulation has been shown to drive neurogenic inflammation in a nitroglycerin-induced migraine model, with muscarinic antagonism attenuating mast cell activation (PMID 36485173).

Given this mechanistic landscape, atropine's blockade of muscarinic receptors could theoretically interrupt the parasympathetic limb of trigeminovascular activation. A 1986 clinical observation lends partial support: systemic atropine administration markedly reduced attack-related sweating, lacrimation, and nasal secretion in chronic paroxysmal hemicrania patients (PMID 2943405) — a related trigeminal autonomic headache condition sharing pathophysiological features with migraine. However, all supporting evidence remains at the animal/mechanistic or historical case-observation level. No prospective human clinical trial has directly tested atropine as a migraine treatment, and the predictive signal is best categorised as a mechanistically plausible research hypothesis rather than a clinically validated indication.

Clinical Trial Evidence

Currently no clinical trials testing atropine directly for migraine disorder are registered in ClinicalTrials.gov or ICTRP.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
2943405	1986	Clinical Observation	Cephalalgia	Systemic atropine markedly reduced attack-associated autonomic symptoms (sweating, lacrimation, nasal secretion) in 4 chronic paroxysmal hemicrania patients — direct but small-scale evidence of anticholinergic effect on a trigeminal autonomic headache
36485173	2024	Animal / Mechanistic	Eur J Neuroscience	Meningeal mast cell–mediated cholinergic modulation drives neurogenic inflammation in nitroglycerin migraine model; muscarinic antagonism (atropine-class agents) attenuated mast cell activation and dural sensitisation
9344563	1997	Animal Study	Exp Neurology	Sphenopalatine ganglion stimulation triggers dural plasma extravasation and mast cell degranulation; establishes the parasympathetic pathway as a potential anticholinergic drug target in migraine
8930196	1996	Animal Study	J Pharmacol Exp Ther	Central cholinergic system participates in sumatriptan antinociception in rodents; atropine (central muscarinic blockade) partially reversed the analgesic effect, demonstrating bidirectional cholinergic involvement in headache pain modulation
10193781	1999	Animal Study	Br J Pharmacol	Atropine used as pharmacological control in guinea pig basilar artery nicotine-relaxation study; provides mechanistic context for muscarinic vs. nicotinic receptor distinction in migraine-relevant vascular responses
17186568	2007	Review	J Appl Toxicol	Pharmacological characterisation of anisodamine, a naturally occurring atropine derivative; less potent and less toxic than atropine with a similar anticholinergic profile — provides analog class data relevant to safety-efficacy trade-off
15882801	2005	Animal Study	Neurosci Lett	Nicotinic receptor–mediated CGRP release drives facial blood flow changes in a rat model; highlights the nicotinic/muscarinic distinction important for predicting atropine's scope of action in the trigeminovascular system
1786517	1991	Animal Study	Br J Pharmacol	Ergotamine and DHE are potent 5-HT1C receptor agonists in piglet choroid plexus; serotonin–cholinergic receptor cross-talk provides indirect mechanistic context for antimigraine drug pharmacology
27179636	2016	Case Report	Rev Port Cardiol	Takotsubo syndrome after anaesthetic procedure in a paediatric patient; atropine used perioperatively — incidental mention, limited direct relevance to migraine
40590589	2024	Case Report	Pain Med Case Rep	Botulinum toxin–induced dropped head in a chronic migraine patient; highlights the parasympathetic/autonomic complexity of migraine management and the clinical importance of cholinergic modulation (indirect)

Singapore Market Information

Atropine has no active marketing authorizations recorded in the Singapore Health Sciences Authority (HSA) database.

Authorization Number	Product Name	Dosage Form	Approved Indication
—	—	—	No registered products found

Atropine is a WHO Essential Medicine and is likely available in Singapore through hospital formularies, government health systems, or import channels despite the absence of commercial HSA registrations in this dataset.

Safety Considerations

Please refer to the package insert for safety information.

Pharmacologically Predictable Risks (general knowledge, no package insert data available): Atropine's anticholinergic mechanism produces well-characterised class effects including tachycardia, urinary retention, dry mouth, constipation, blurred vision, cognitive impairment (at high doses), and acute angle-closure glaucoma in predisposed patients. For the open-angle glaucoma indication (rank 5 in this Evidence Pack), modern evidence indicates that atropine raises intraocular pressure through mydriasis/cycloplegia-mediated trabecular outflow reduction (PMID 39027062; PMID 40932733), representing a direct contraindication to any repurposing attempt in this population.

Conclusion and Next Steps

Decision: Hold

Rationale: All current evidence supporting atropine for migraine disorder is preclinical or mechanistic in nature (L4). While the parasympathetic/cholinergic hypothesis for migraine has biological plausibility and a single 1986 clinical observation in a related headache type is encouraging, no human clinical trial has tested this hypothesis. Atropine is also not marketed in Singapore, adding a regulatory barrier. This indication is best categorised as a research question, not a clinical development candidate at this stage.

Higher-Evidence Application — Post-Dural Puncture Headache (Rank 8: "Headache Disorder", Evidence Level L2)

The neostigmine+atropine combination has been tested in multiple randomised trials specifically for post-dural puncture headache (PDPH):

Trial	Phase	Status	n	Key Finding
NCT04910477	Phase 3	Completed	90	Nebulised neostigmine/atropine vs dexmedetomidine for PDPH after caesarean section — direct head-to-head RCT
NCT03997006	Phase 4	Completed	60	IV aminophylline vs IV neostigmine/atropine for PDPH treatment — efficacy and safety comparison
NCT06729047	Phase 1/2	Not Yet Recruiting	330	IV neostigmine+atropine vs ketorolac prophylaxis for PDPH — largest planned trial, results pending

Supporting RCT literature: PMID 30169405 (Anesthesia & Analgesia 2018) and PMID 36651373 (Minerva Anestesiologica 2023).

Critical Caveat: In all PDPH trials, atropine functions as a safety co-medication to prevent neostigmine-induced bradycardia and hypersalivation — not as the primary therapeutic agent. Atropine's independent contribution to headache relief has not been isolated in any existing trial design.

To advance the migraine disorder hypothesis (rank 1), the following is needed:

A human proof-of-concept study testing intranasal or systemic atropine during the prodromal/attack phase of migraine
Mechanistic data on atropine's effect on sphenopalatine ganglion activity in migraine patients (e.g., via SPG stimulation/block paradigms)
Pharmacokinetic/pharmacodynamic modelling to identify a dose window that blocks parasympathetic-mediated trigeminovascular activation without causing intolerable systemic anticholinergic side effects
Safety profile characterisation in the migraine-prone population (predominantly young women of reproductive age)
TFDA/HSA package insert data to fill the current safety data gap (DG001)
DrugBank MOA data to complete the mechanistic rationale (DG002)

To advance the PDPH application (rank 8) toward a standalone atropine label:

Design a three-arm RCT isolating atropine vs. neostigmine vs. neostigmine+atropine to parse each drug's contribution
Await and evaluate results from NCT06729047 (n=330)
Assess whether a regulatory pathway for the combination product is feasible under HSA Singapore
Disclaimer

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