Phenyltoloxamine
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Phenyltoloxamine: From Allergic Rhinitis and Urticaria to Allergic Urticaria
One-Sentence Summary
Phenyltoloxamine is a first-generation H1-antihistamine, originally used for allergic and vasomotor rhinitis, the common cold, allergic conjunctivitis and urticaria or angioedema. The TxGNN model predicts it may be effective for allergic urticaria, but there are currently 0 clinical trials and 0 publications supporting this direction. The prediction is largely an extension of an existing indication, supported by drug-class reasoning only.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Allergic rhinitis, vasomotor rhinitis, common cold, allergic/atopic conjunctivitis, urticaria, angioedema (the Singapore licence has no indication text recorded) |
| Predicted New Indication | Allergic urticaria |
| TxGNN Prediction Score | 96.24% |
| Evidence Level | L4 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 1 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available from the data compiled for this report. Based on known information, phenyltoloxamine is a first-generation H1-antihistamine. Blocking the H1 receptor reduces histamine-driven itching, swelling and redness.
Urticaria and angioedema are already among its original indications, and allergic urticaria is a subtype of urticaria. The high TxGNN score is therefore mechanistically consistent. However, this is largely an on-label extension rather than true repurposing. No phenyltoloxamine-specific trials or literature were available, so the rationale rests on drug-class reasoning only.
Other top predictions (all Hold, no clinical evidence):
| Rank | Predicted Indication | Score | Evidence Level | Assessment |
|---|---|---|---|---|
| 2 | Rosacea conjunctivitis | 95.19% | L5 | Antihistamine benefit is speculative, since the disease is driven mainly by meibomian gland dysfunction, inflammation and Demodex |
| 3 | Cold urticaria | 93.25% | L4 | Plausible, since H1-antihistamines are first-line as a class, but second-generation agents are preferred in practice |
| 4 | Anorectal stricture | 91.83% | L5 | No clear mechanistic link |
| 5 | Acute laryngopharyngitis | 91.76% | L5 | Possible symptomatic relief only. Drying effects may worsen throat irritation |
| 6 | Pharyngitis | 90.91% | L5 | Possible relief of rhinorrhoea and postnasal drip only, with no effect on the underlying infection |
| 7 | Anal polyp | 90.75% | L5 | No plausible link, likely a knowledge-graph artifact |
| 8 | Proctitis | 89.66% | L5 | Not an established treatment. Anticholinergic effects may be undesirable |
| 9 | Nasal cavity disease | 89.13% | L4 | Too broad. Partly explained by the approved rhinitis indications |
| 10 | Recalcitrant atopic dermatitis | 88.39% | L5 | Histamine is not the main driver, and guidelines do not support antihistamines for disease control |
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN13319P | Codipront Capsule (CTS Chemical Industries Ltd) | Capsule, extended release (oral) | Not recorded |
Safety Considerations
- Contraindications (from the TxGNN knowledge graph, not label text): The graph links the drug to contraindications in the following conditions.
- Cardiovascular: hypertension, coronary artery disease, myocardial infarction, coronary thrombosis
- Hepatic and renal: liver failure, liver disease, kidney disease, impaired renal function, gallbladder disease
- Respiratory: COPD (including severe early-onset)
- Neurological and psychiatric: epilepsy, insomnia, substance abuse or dependence
- Gastrointestinal: pancreatitis, peptic ulcer disease, gastritis
- Metabolic: diabetes mellitus, diabetic ketoacidosis, gout
- Haematological: thrombocytopenia, blood coagulation disease, haemophilia, haemoglobinopathy, anaemia (including macrocytic)
- Urological: benign prostatic hyperplasia, pyoureter
- Drug Interactions: 72 interactions were identified in total.
- Major: potassium chloride and potassium citrate.
- Moderate (examples):
- Anticholinergics: atropine, hyoscyamine, scopolamine, glycopyrronium, dicyclomine, clidinium, propantheline, methscopolamine, mepenzolate
- Opioids and antidiarrhoeals: morphine, opium, loperamide, eluxadoline
- Cannabinoids: dronabinol, nabilone
- Others: metoclopramide
Label-based warnings and contraindications were not available. Please refer to the package insert for full safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The top prediction, allergic urticaria, is mechanistically sensible but largely overlaps with an existing indication. No trials or literature specific to phenyltoloxamine support it. The remaining predictions are speculative or lack a plausible mechanism. Safety screening cannot proceed without the package insert.
To proceed, the following is needed:
- Package insert warnings and contraindications from the HSA, since this is a blocking gap
- Detailed mechanism of action data (for example, from DrugBank)
- Phenyltoloxamine-specific clinical or literature evidence for allergic urticaria and cold urticaria
- Confirmation of the approved indication text for SIN13319P, which appears to be a combination product (Codipront) listed as a single-ingredient licence
- Route and formulation compatibility assessment, since only an oral extended-release capsule is registered
- A clear comparison against second-generation antihistamines, given their preferred role and the anticholinergic burden of this drug
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.