Chloroquine and hydroxychloroquine ototoxicity; potential implications for SARS-CoV-2 treatment. A brief review of the literature

Introduction: Current clinical evidences do not support any specific treatment against SARS-CoV-2. Chloroquine (CQ) and hydroxychloroquine (HCQ) are typically used in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria; they have been considered for off-label and compassionate use in several countries against moderate to severe cases of COVID-19 and there's actually a massive demand of these two drugs. The aim of this paper is to briefly review the published literature, summarizing evidences about audiological implications after CQ and HCQ treatment.

Methods: We conducted a review of the literature on Medline and Pubmed platforms from 27th May 2020 to 30 May 2020. We combined MeSH terms of "chloroquine", "hydroxychloroquine", "ototoxicity", "hearing loss", "tinnitus", "deafness" and "hearing". Publications with relevant data were included. Selected data (authors, country and year; sample size; study design; audiological side effects) were extracted and summarized in a table.

Results: Of 45 initial studies, 14 met inclusion criteria. The authors found xix cases of HCQ ototoxicity; Tinnitus was reported in 2 cases, and it was found to be reversible or irreversible. Sensorineural hearing loss after HCQ use was reported in 7 patients; it was found to be irreversible or partially reversible after discontinuation of HCQ in 6 cases. Eight papers reporting CQ ototoxicity were; tinnitus was not reported by any authors. Sensorineural hearing loss after taking CQ was reported in 6 patients; it was found to be irreversible after discontinuation of CQ in 5 patients. One patient showed abnormal gait after a single intramuscular injection of CQ. Thirteen patients' Auditory Brainstem Response (ABR) were found to be abnormal, but they resolved after CQ discontinuation.

Conclusions: CQ and HCQ related ototoxicity is widely reported in the literature although the pathophysiological mechanism is not well known. Current data are not sufficient enough to support the use of CQ and HCQ as therapy for COVID-19, but considering the growing demand for these two drugs and the number of people around the world who have taken and will take CQ and HCQ, it must necessarily consider the clinical and social impact of long term audiological side effects.