Terazosin

證據等級: L5

預測適應症: 10 個

Terazosin: From Hypertension/BPH to Raynaud Disease

One-Sentence Summary

Terazosin is a selective alpha-1 adrenergic receptor (α1-AR) blocker, globally established for hypertension and benign prostatic hyperplasia (BPH), though not currently registered in Taiwan. The TxGNN model predicts it may be effective for 10 conditions across vascular, neurological, and hair-related disorders. Of these, Raynaud disease emerges as the most actionable candidate — backed by 1 direct clinical study and the strongest mechanistic rationale — reaching a “Proceed with Guardrails” recommendation at evidence level L3.

Quick Overview

Item	Content
Original Indication	Hypertension, Benign Prostatic Hyperplasia (global use; not registered in Taiwan)
Top Actionable Indication	Raynaud disease
TxGNN Prediction Score (Raynaud)	99.83%
Evidence Level	L3 (observational/clinical pilot study)
Taiwan Market Status	✗ Not marketed
Number of Licenses	0
Recommended Decision	Proceed with Guardrails (Raynaud disease)

All Predicted Indications at a Glance

Rank	Disease	TxGNN Score	Evidence Level	Decision	Recommendation
1	Hypotrichosis simplex of the scalp	99.97%	L5	S0	Hold
2	Congenital hypotrichosis milia	99.97%	L5	S0	Hold
3	Diffuse alopecia areata	99.96%	L5	S0	Hold
4	Alopecia	99.95%	L4	S0	Research Question
5	Migraine disorder	99.92%	L3	S1	Research Question
6	Migraine with brainstem aura	99.91%	L4	S1	Research Question
7	Raynaud disease	99.83%	L3	S2	Proceed with Guardrails
8	Ambras type hypertrichosis universalis congenita	99.65%	L5	S0	Hold
9	Manic bipolar affective disorder	99.55%	L5	S0	Hold
10	Kyphoscoliotic heart disease	99.49%	L5	S0	Hold

Note: Ranks 1–3 and 8 (hair quantity disorders) are flagged as ontology spillover — TxGNN places them in graph proximity to alopecia-related nodes, but α1-AR pharmacology has no direct mechanistic link to structural hair or keratin gene defects. These are artifact predictions.

Why is This Prediction Reasonable?

Terazosin belongs to the quinazoline class of selective α1-adrenergic receptor antagonists. By blocking postsynaptic α1-AR in vascular smooth muscle, it prevents norepinephrine-induced vasoconstriction, resulting in vasodilation and blood pressure reduction. In BPH, the same mechanism relaxes smooth muscle in the prostate and bladder neck, improving urinary flow.

Raynaud disease is mechanistically the most direct translation of this pharmacology. The condition is defined by episodic peripheral vasospasm — triggered by cold or emotional stress — driven by excessive sympathetic α1-AR activation in digital arteries and arterioles. Blocking α1-AR directly interrupts this spasm cascade, restoring perfusion to fingers and toes. This is not extrapolation; it is the same receptor, the same tissue response, in a different clinical context. Related drugs in the same class — prazosin and doxazosin — already have documented clinical use in Raynaud’s phenomenon, establishing a class-level precedent.

For migraine (ranks 5–6), the rationale is more speculative: α1-AR activation in extracranial vessels may contribute to the vascular component of migraine, and terazosin’s vasodilatory effect could theoretically blunt this. However, modern migraine pathophysiology centers on CGRP signaling and trigeminal neurovascular activation, making α1 blockade a peripheral and incomplete mechanism. The alopecia cluster (ranks 1–4) represents TxGNN graph topology artifacts for the genetic/structural subtypes (L5), with only a weak indirect hypothesis for the generic “alopecia” node — scalp microvascular expansion is biologically plausible but has never been tested.

Literature Evidence — Raynaud Disease

PMID	Year	Type	Journal	Key Findings
9273472	1997	Clinical Study (open-label pilot)	Minerva cardioangiologica	Terazosin significantly reduced the number, intensity, and duration of vasospastic attacks in both idiopathic and secondary Raynaud’s phenomenon; telethermography and ultrasonography findings also improved

Literature Evidence — Migraine Disorder

PMID	Year	Type	Journal	Key Findings
7911406	1994	Clinical Study (non-randomized pilot)	La Clinica terapeutica	Open trial in 46 migraine-without-aura patients; terazosin group (n=10) showed prophylactic activity against paroxysmal headache; also studied buflomedil and combination
9074296	1997	Review / Commentary	Headache	Personal experience series (n=10) placing patients on terazosin or doxazosin; 9/10 showed reduction in migraine frequency or severity; 5 discontinued due to side effects (mainly dizziness/orthostatic hypotension)

Literature Evidence — Alopecia

PMID	Year	Type	Journal	Key Findings
34779371	2022	Narrative Review	Current Cardiology Reviews	Review of extracardiac effects of cardiovascular medications; mentions minoxidil’s hirsutism side effect as a drug repurposing example — does not directly study terazosin for alopecia; included as contextual background on vasodilator-hair follicle biology

Clinical Trial Evidence

No registered clinical trials were identified for terazosin in any of the 10 predicted indications.

Taiwan Market Information

Terazosin is not currently registered in Taiwan (0 approved licenses). Safety and prescribing information should be obtained from the originator’s global package insert (Hytrin® / Abbott Laboratories).

Safety Considerations

No Taiwan-specific package insert data, drug interaction data, or formal contraindication records were retrieved in this Evidence Pack.

Please refer to the originator’s package insert (Hytrin® global label) for complete safety information, including warnings on first-dose orthostatic hypotension, syncope risk (especially in combination with PDE5 inhibitors), and use in patients with hepatic impairment.

Conclusion and Next Steps

Decision: Proceed with Guardrails — for Raynaud disease only

Rationale: Terazosin’s mechanism of α1-AR blockade directly addresses the sympathetically-driven vasospasm that defines Raynaud disease, and a published clinical pilot demonstrates measurable benefit in both idiopathic and secondary forms. Class-level evidence from prazosin and doxazosin further supports feasibility.

To proceed, the following is needed:

Controlled trial design: The existing evidence (PMID 9273472) is open-label with no control arm; a randomized, placebo-controlled crossover study is required to establish efficacy
Dose optimization: Raynaud management doses for other α1 blockers are typically lower than antihypertensive doses; appropriate dosing for terazosin needs prospective evaluation
Taiwan regulatory pathway: Terazosin has no Taiwan license; regulatory strategy (off-label use protocol vs. NDA filing) must be defined before clinical application
Orthostatic hypotension monitoring plan: The most clinically significant safety concern — patients with Raynaud often have lower baseline blood pressure; fall-risk protocol needed
Comparison arm consideration: Calcium channel blockers (nifedipine) are first-line for Raynaud’s; any study should benchmark against current standard of care
MOA data retrieval: Full DrugBank pharmacology record should be obtained to confirm receptor selectivity profile and complete the mechanistic documentation

⚠️ Disclaimer: This report is for research reference purposes only and does not constitute medical advice. All drug repurposing candidates require clinical validation before therapeutic application.

Disclaimer

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