Hydrochlorothiazide and risk of hearing disorder: a case series.

BACKGROUND: Hydrochlorothiazide is not known to cause hearing disorder. The Eritrean Pharmacovigilance Centre, however, has received cases of hearing disorder, including irreversible deafness, associated with hydrochlorothiazide. The aim of this study is, therefore, to assess the causal relationship between hydrochlorothiazide and hearing disorder.

METHODS: Data was retrieved from the WHO global adverse drug reaction database, VigiBase™. A search on VigiBase™ was made on August 6, 2017 using "hydrochlorothiazide" as drug substance, and "ototoxicity", "decreased hearing", and "vestibular disorder" as reaction terms. Cases were retrieved using VigiLyze™ and exported to an Excel spreadsheet for descriptive analysis. Causality was assessed using Austin Bradford-Hill criteria and labeledness of the reaction was evaluated through a thorough literature review including the summary of product characteristics.

RESULTS: From 1972 to August 2017, 94 cases of hearing disorder associated with hydrochlorothiazide were submitted from 18 countries to VigiBase™. The median age was 64 years with almost equal male to female ratio. In 53.2% of the cases, hydrochlorothiazide was reported as the only suspected drug. Of these, 26 cases encountered hearing disorder following the sole intake of hydrochlorothiazide. Reaction was marked as "serious" in 36% of the cases and median time to reaction onset was 3 days. Outcome was reported as reversible in 66.7% of the cases. Reaction resolved in 17 cases following withdrawal of hydrochlorothiazide and recurred in one case after subsequent rechallenge with the product. Consistency of cases and a dose-response relationship was also observed in this case series.

CONCLUSIONS: This case series assessment found a suggestive causal relationship between hydrochlorothiazide and hearing disorder. Taking the inherent limitations of this study into account, results should be interpreted with caution and further studies are required to validate the safety signal.