Drug-Associated Vanishing Bile Duct Syndrome: Screening for Potential Pharmaceutical Triggers Using the WHO Pharmacovigilance Database

Vanishing bile duct syndrome (VBDS) is a rare cholestatic liver disease often associated with drug-induced liver injury, yet systematic data on pharmaceutical triggers remain limited. Using WHO VigiBase, we applied Bayesian disproportionality analysis (IC0.25) to identify drug-event associations that may not be readily apparent in clinical trials or pre-marketing studies. Product labels approved by Swissmedic or the FDA, as well as LiverTox, were reviewed to determine whether VBDS was already acknowledged as an adverse event. Signal detection was deliberately restricted to reports naming a single suspect drug. Among these single-agent reports, 22 drugs demonstrated a positive IC0.25 signal, of which nevirapine, dapsone and azithromycin showed the strongest disproportionality signal. Only one of these agents (carbamazepine) explicitly labelled VBDS as an adverse event. These findings are based on spontaneous reporting data: disproportionality analysis is a hypothesis-generating signal-detection method that does not establish causality and requires further validation. This study expands the current understanding of drug-induced VBDS by reinforcing the associations with known drugs and generating pharmacovigilance signals for new potential VBDS triggers across several drug categories.