Domperidone

證據等級: L5

預測適應症: 1 個

Domperidone: From Nausea and Vomiting to Nephrogenic Syndrome of Inappropriate Antidiuresis

One-Sentence Summary

Domperidone is a peripherally-acting dopamine D2 receptor antagonist widely used as a prokinetic and antiemetic agent for nausea, vomiting, and gastroparesis. The TxGNN model predicts it may be effective for Nephrogenic Syndrome of Inappropriate Antidiuresis (NSIAD), however, with 0 clinical trials and 0 publications currently supporting this direction, and a mechanistic rationale assessed as extremely weak, this candidate warrants caution before further investment.

Quick Overview

Item	Content
Original Indication	Not available (drug not marketed in Canada; no DIN on record)
Predicted New Indication	Nephrogenic Syndrome of Inappropriate Antidiuresis (NSIAD)
TxGNN Prediction Score	99.08%
Evidence Level	L5
Canada Market Status	Not marketed
Number of DINs	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in this evidence pack. Based on established pharmacology, Domperidone is a peripherally-acting dopamine D2 receptor antagonist that does not cross the blood-brain barrier. Its therapeutic effects are confined primarily to the gastrointestinal tract and the chemoreceptor trigger zone, where D2 blockade accelerates gastric emptying and suppresses nausea.

NSIAD is a rare X-linked genetic disorder caused by gain-of-function mutations in the AVPR2 gene, leading to constitutive activation of the V2 vasopressin receptor independent of circulating ADH levels. This drives sustained intracellular cAMP elevation, persistent upregulation of aquaporin-2 (AQP2) water channels in the renal collecting duct, and consequently chronic, dilutional hyponatremia that does not respond to standard SIADH treatments such as fluid restriction.

The mechanistic connection between Domperidone and NSIAD is extremely tenuous. While the renal dopamine D1/D2 system is known to modulate AQP2 membrane trafficking under normal physiological conditions, this compensatory pathway is overwhelmed by the constitutive AVPR2 mutation in NSIAD, leaving minimal therapeutic space for dopaminergic intervention. Since Domperidone does not cross the blood-brain barrier, it cannot modulate hypothalamic ADH release — a route irrelevant to NSIAD in any case, given that ADH is already suppressed. Critically, there is a theoretical adverse risk: blocking renal dopamine’s compensatory downregulation of AQP2 could worsen hyponatremia rather than relieve it. The TxGNN high score (99.08%) most likely reflects indirect graph connections between D2 receptor nodes and water-electrolyte regulation nodes in the knowledge graph, rather than a genuine therapeutic pathway.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

Currently no related literature available.

Canada Market Information

Domperidone currently holds no Drug Identification Numbers (DINs) in Canada. No approved product licenses are on record.

Note: Domperidone has a complex regulatory history in North America. Health Canada has restricted its availability due to cardiac safety concerns (QT prolongation and risk of sudden cardiac death), and it is not approved for routine sale. This regulatory context is an additional barrier relevant to any repurposing strategy.

Safety Considerations

Safety data (key warnings, contraindications, and drug-drug interactions) were not retrievable for this evidence pack. Please refer to the package insert and Health Canada product monograph for safety information.

Known class concern: Domperidone carries a well-documented risk of QT interval prolongation and ventricular arrhythmia, particularly at higher doses or in patients with pre-existing cardiac conditions or electrolyte imbalances. NSIAD patients are characteristically hyponatremic; hyponatremia itself prolongs the QT interval, potentially compounding cardiac risk if Domperidone were used in this population. This interaction deserves specific attention in any future evaluation.

Conclusion and Next Steps

Decision: Hold

Rationale: This candidate is supported exclusively by a computational model prediction (L5 evidence), with zero clinical trials, zero observational data, and zero published literature linking Domperidone to NSIAD. The mechanistic rationale is not merely weak — it identifies a plausible pathway toward harm (worsening hyponatremia via D2-mediated AQP2 upregulation), and the drug’s known cardiac safety profile (QT prolongation) presents additional risk in a population with baseline electrolyte disturbance. The high TxGNN score appears to be a knowledge-graph artefact rather than a signal of genuine therapeutic opportunity.

To proceed, the following is needed:

Formal MOA documentation from DrugBank to confirm or refute the D2/AQP2 interaction hypothesis
Safety data package: full warnings, contraindications, and drug interaction profile (package insert / Health Canada monograph)
A preclinical proof-of-concept study demonstrating measurable, beneficial effect of D2 antagonism in an Avpr2-gain-of-function animal model before any human hypothesis is entertained
Cardiac safety assessment specifically addressing QT risk in hyponatremic patients, given the known electrolyte abnormality in NSIAD
Expert nephrology consultation (rare electrolyte disorders) to evaluate whether any biological rationale exists that the current evidence pack does not capture
Re-evaluation of the TxGNN knowledge graph path to determine whether the high score is driven by a spurious multi-hop connection

⚠️ Disclaimer: This report is for research reference purposes only and does not constitute medical advice. Drug repurposing candidates require clinical validation before any therapeutic application. All findings should be interpreted in the context of regulatory requirements and clinical oversight.

Disclaimer

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