Unresolved gustatory, olfactory and auditory adverse drug reactions to antibiotic drugs: a survey of spontaneous reporting to Eudravigilance

Objectives: Sensory adverse drug reactions (ADRs) are generally expected to be transient in nature. However, spontaneous reports describe frequently these events as long-lasting or unresolved. In this study, the authors reviewed the Eudravigilance publicly accessible database to describe the volume and expectedness of potentially unresolved outcomes for gustatory, olfactory and auditory (GOA) suspected ADRs associated with antibiotics for systemic use. Methods: 'Overall' and 'GOA' suspected ADRs were extracted from Eudravigilance to estimate the distribution of their outcomes among different antibiotic groups. Then, the authors identified the drugs contributing to at least 15% of all suspected GOA ADRs observed for the antibiotic groups, and evaluated the expectedness. Results: The frequency of persistent/permanent outcomes was higher for GOA suspected ADRs, as compared to the overall ones. Unresolved and undetermined outcomes for antibiotic-associated GOA ADRs in Eudravigilance might hide a large number of events with underestimated clinical consequences. Several persistent/permanent antibiotic-associated GOA reactions could be classified as serious and unexpected. Conclusion: Potential long-lasting or irreversible GOA reactions are often reported for all antibiotics drugs. Further studies are warranted to clarify whether this is an actual safety issue or simply it reflects a general difficulty in outcomes assessment for such reactions.