Atropine

證據等級: L5

預測適應症: 10 個

Atropine: From Anticholinergic Agent to Migraine Disorder

One-Sentence Summary

Atropine is a classical antimuscarinic agent widely used in clinical medicine for bradycardia management, organophosphate poisoning, and as a preanesthetic agent — though it holds no current TGA registration in Australia. The TxGNN model assigns it a 99.56% prediction confidence for Migraine Disorder, supported by 0 clinical trials and 13 publications that are predominantly animal studies and mechanistic research exploring the parasympathetic pathway in migraine pathophysiology. No human clinical trials have been conducted on atropine specifically for migraine to date, and all supporting evidence currently remains at the preclinical level.

Quick Overview

Item	Content
Original Indication	Not registered in Australia (no ARTG approval)
Predicted New Indication	Migraine Disorder
TxGNN Prediction Score	99.56%
Evidence Level	L4 — Preclinical / Mechanistic Studies
Australia Market Status	Not marketed
Number of ARTG Entries	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Although DrugBank MOA data was not retrieved for this report (data gap DG002), atropine’s mechanism of action is extensively characterised in the biomedical literature. It is a competitive, non-selective antagonist of muscarinic acetylcholine receptors (M1–M5), acting principally on M2 and M3 subtypes to suppress parasympathetic effector responses — reducing glandular secretion, relaxing smooth muscle, and modulating vascular tone. These properties form the pharmacological basis of the migraine prediction.

Migraine pathophysiology centres on activation of the trigeminoparasympathetic reflex arc via the sphenopalatine ganglion (SPG), which drives dural vasodilation, plasma protein extravasation, and CGRP release — collectively producing the neurogenic inflammation associated with migraine pain. PMID 9344563 (1997) directly demonstrated that parasympathetic SPG stimulation in rats induces dural plasma protein extravasation, the hallmark of neurogenic inflammation. More recently, PMID 36485173 (2024, European Journal of Neuroscience) investigated muscarinic antagonism — atropine’s core mechanism — in a nitroglycerin-induced rat migraine model, specifically examining the meningeal mast cell–cholinergic axis as a driver of neurogenic inflammation. PMID 8930196 showed that central cholinergic transmission is required for sumatriptan’s antinociceptive effects in rodents, directly linking the cholinergic system to migraine pain modulation. PMID 15882801 further demonstrated that CGRP–nicotinic receptor interactions regulate centrally evoked facial blood flow, relevant to migraine triggers.

The most clinically notable observation comes from PMID 2943405 (1986, Cephalalgia): systemic atropine administration markedly reduced autonomic symptoms — sweating, lacrimation, and nasal secretion — during attacks of chronic paroxysmal hemicrania (a trigeminal autonomic cephalalgia closely related to cluster headache). This represents the only human-level observation in this evidence set directly associating atropine with relief of headache-associated autonomic features. While biologically plausible, the overall evidence base for migraine has not progressed beyond preclinical and mechanistic research, and the TxGNN model’s high-confidence prediction likely reflects the strength of the underlying biological network connectivity between muscarinic blockade and migraine pathology rather than established clinical utility.

Clinical Trial Evidence

Currently no related clinical trials registered for migraine disorder.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
36485173	2024	Mechanistic Study	European Journal of Neuroscience	Muscarinic antagonism in nitroglycerin-induced rat migraine model; meningeal mast cell–cholinergic axis shown to modulate neurogenic inflammation — most direct mechanistic support for atropine’s predicted role
9344563	1997	Animal Study	Experimental Neurology	Parasympathetic SPG stimulation directly induces dural plasma protein extravasation in rats; establishes parasympathetic neurogenic inflammation as a therapeutically targetable mechanism
8930196	1996	Animal Study	J Pharmacol Exp Ther	Central cholinergic system (ACh pathway) shown to mediate sumatriptan antinociception in rodents; atropine used to confirm muscarinic pathway dependency
2943405	1986	Clinical Observation	Cephalalgia	Systemic atropine markedly reduced sweating, lacrimation, and nasal secretion during chronic paroxysmal hemicrania attacks — the only human-level evidence of atropine relieving headache-associated autonomic features
15882801	2005	Animal Study	Neuroscience Letters	CGRP and nicotinic receptors shown to regulate centrally evoked facial blood flow; mechanistic relevance to CGRP-mediated vascular changes in migraine
10193781	1999	Animal Study	British J Pharmacology	Atropine used as pharmacological tool in guinea-pig basilar artery model; characterises nicotinic-mediated vascular relaxation in a migraine-relevant intracranial vessel
17186568	2007	Pharmacology Review	J Applied Toxicology	Review of anisodamine, a naturally occurring atropine derivative; characterises class-level pharmacological properties and differential CNS toxicity profile compared with atropine and scopolamine
1786517	1991	Animal Study	British J Pharmacology	Ergotamine and DHE characterised as 5-HT1C agonists in piglet choroid plexus; mechanistic context for receptor-level pharmacology in established antimigraine agents
21252	1977	Mechanistic Study	J Pharmacy and Pharmacology	Early investigation of beta-phenethylamine as a migraine trigger; establishes historical mechanistic framework for autonomic contributions to migraine
40590589	2024	Case Report	Pain Medicine Case Reports	Botulinum toxin (anticholinergic mechanism class) used for chronic migraine; provides treatment context for autonomic-targeting pharmacotherapy in migraine management

Australia Market Information

Atropine (DrugBank ID: DB00572) is not currently registered on the Australian Register of Therapeutic Goods (ARTG) and has no approved product listings in Australia.

While atropine is used clinically in Australian healthcare — including in hospital formularies for acute bradycardia, organophosphate poisoning (typically alongside pralidoxime), ophthalmic mydriasis/cycloplegia, and as a preanesthetic agent — these clinical uses typically operate via hospital formulary pathways, TGA Special Access Scheme (SAS) provisions, or supply as an unlisted hospital medicine rather than through formal ARTG product registration with approved indications.

Any proposed off-label or repurposing use would require engagement with the TGA Special Access Scheme Category B or C, or relevant hospital pharmacy governance and ethics review processes, before clinical administration.

Safety Considerations

Detailed safety information including TGA-approved contraindications, key prescribing warnings, and drug interaction data was not available in this Evidence Pack. Please refer to the relevant Product Information (PI), the Australian Medicines Handbook (AMH), or eTG Complete for comprehensive safety guidance.

The following signals are noted from available literature and this Evidence Pack’s predicted indications:

Glaucoma contraindication: Atropine causes mydriasis and cycloplegia, increasing the risk of acute angle-closure glaucoma. It is contraindicated in narrow-angle glaucoma. Two predicted indications from this Evidence Pack — open-angle glaucoma (rank 5) and primary hereditary glaucoma (rank 6) — carry explicit safety flags and are not recommended for further development.
Reversible Cerebral Vasoconstriction Syndrome (RCVS): PMID 37802666 (2023, British J Anaesthesia) documents a case of RCVS following neostigmine/atropine administration for post-dural puncture headache — a directly relevant safety signal for any neurological indication.
Cardiovascular effects: Tachycardia and arrhythmia risk are expected class effects; relevant at all doses and particularly important in perioperative or neurological applications.
CNS anticholinergic effects: Confusion, agitation, and hallucinations — greater risk in elderly patients and at supratherapeutic doses; relevant to central nervous system indications including migraine.

Conclusion and Next Steps

Decision: Hold

Rationale: The TxGNN model’s 99.56% prediction confidence for migraine disorder is mechanistically coherent — the role of the cranial parasympathetic system (SPG activation, CGRP release, dural neurogenic inflammation) provides clear biological plausibility for muscarinic blockade as a therapeutic strategy. However, all current supporting evidence remains preclinical or mechanistic (Evidence Level L4), with zero human clinical trials of atropine in migraine. Combined with the absence of Australian market registration, a Hold decision is appropriate for this indication until translational evidence is generated.

High-Priority Secondary Signal — Headache Disorder / Post-Dural Puncture Headache (PDPH):

A more immediately actionable signal was identified for the related indication of headache disorder (TxGNN rank 8, score 97.24%, Evidence Level L2). Neostigmine combined with Atropine has been studied in Phase 3 RCTs for post-dural puncture headache (PDPH) — a specific and clinically significant headache subtype. Key trials include:

Trial	Phase	Status	n	Key Findings
NCT04910477	Phase 3	Completed	90	Nebulised Dexmedetomidine vs Neostigmine/Atropine for PDPH post-caesarean section — completed head-to-head comparison
NCT03997006	Phase 4	Completed	60	IV Aminophylline vs IV Neostigmine/Atropine for PDPH treatment
NCT06729047	Phase 1/2	Not yet recruiting	330	Prophylactic IV Neostigmine+Atropine vs Ketorolac for PDPH prevention — large planned sample
NCT06824025	Early Phase 1	Not yet recruiting	111	Nebulised Neostigmine/Atropine vs Lignocaine for acute PDPH

This signal is further supported by published RCTs: PMID 30169405 (Anesthesia & Analgesia, 2018) and PMID 36651373 (Minerva Anestesiologica, 2023). A dedicated report on Headache Disorder / PDPH is recommended and would likely result in a Proceed with Guardrails recommendation.

To proceed on migraine disorder, the following is needed:

Formal MOA data retrieval from DrugBank API (resolving data gap DG002)
A systematic review or scoping review of muscarinic antagonism in migraine and trigeminal autonomic cephalalgias
A dedicated preclinical study testing atropine as a therapeutic candidate (not merely as a pharmacological tool) in a validated migraine animal model, with translatable endpoints
Safety and tolerability profiling at neurologically relevant dosing ranges, with attention to the RCVS signal
TGA Special Access Scheme or hospital pharmacy governance consultation before any clinical administration is considered
Disclaimer

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