Arrhythmia phenotypes in hair-loss therapies: insights from minoxidil and finasteride reports in eudravigilance
Y Shhab, Z A Stepanov, S Aoun, S Stoleru, A ZugravuAbstract
Background
Minoxidil and finasteride are widely used therapies for androgenetic alopecia, yet their cardiovascular safety profiles remain insufficiently characterised in real-world populations. Minoxidil, originally developed as an antihypertensive vasodilator, is known to activate sympathetic tone and increase heart rate, providing a plausible pathway for supraventricular arrhythmias. Conversely, finasteride alters androgen signalling, and reduced androgen levels have been linked to changes in ventricular ion-channel expression, QT dynamics, and arrhythmic vulnerability in men, suggesting a potential mechanism for ventricular arrhythmias. Post-marketing pharmacovigilance data may therefore reveal distinct arrhythmia phenotypes that correspond to these mechanistic pathways.
Objective
To compare arrhythmia-related adverse event reporting for minoxidil and finasteride and explore potential differences in supraventricular versus ventricular phenotypes.
Methods
EudraVigilance Individual Case Safety Reports submitted up to 09/11/2025 were extracted for minoxidil (n = 9,560) and finasteride (n = 9,348). Rhythm-related Preferred Terms were grouped into supraventricular and ventricular categories. Disproportionality was assessed using reporting odds ratios (RORs) with 95 percent confidence intervals.
Results
Minoxidil was linked to 589 arrhythmia reports versus 380 for finasteride, yielding a significant disproportionality signal (ROR 1.70, 95 percent CI 1.49–1.93). Minoxidil reports showed a predominance of supraventricular symptoms, including tachycardia, palpitations, and sinus-node–related events, consistent with reflex sympathetic activation. Finasteride reports—originating almost exclusively from male users—contained a proportionally higher share of ventricular events such as ventricular extrasystoles and ventricular tachycardia, aligning with the male-associated baseline vulnerability to ventricular arrhythmias.
Conclusion
Minoxidil demonstrates a supraventricular arrhythmia reporting pattern, whereas finasteride shows relatively greater ventricular involvement. These divergent profiles support the need for mechanistic and prospective evaluation.