Detection of Signals for Smell and Taste Disorders Associated with Z-drugs: A Disproportionality Analysis of the FAERS Database.

OBJECTIVE: This study aimed to detect and characterise signals of disproportionate reporting for smell and taste disorders associated with Z-drugs in the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). METHODS: Reports involving Z-drugs and smell/taste disorders were identified using the Standardised MedDRA Query (SMQ) 'Taste and smell disorders'. Disproportionality analyses were performed using the reporting odds ratio (ROR), proportional reporting ratio (PRR), empirical Bayes geometric mean (EBGM), and information component (IC). Sex-stratified, age-stratified, and time-to-onset (TTO) analyses were also conducted. RESULTS: Among 32,853 reports involving Z-drugs, 3,480 were classified as smell- or taste-related adverse events. Eszopiclone accounted for 97.6% of these reports and demonstrated a strong disproportionality signal. Dysgeusia was the predominant adverse event, whereas parosmia and the preferred term 'taste disorder' generated additional positive signals. Signal strength was greatest among adults aged 18 to 45 years, and parosmia showed stronger disproportionality among women. Most events were reported within 30 days after treatment initiation. CONCLUSIONS: FAERS data indicate a strong association between eszopiclone and smell/taste disorders, particularly dysgeusia. Parosmia emerged as an additional signal warranting clinical attention. Further epidemiological and mechanistic studies are needed to clarify the underlying mechanisms and clinical significance of these findings.