Ototoxicity of FDA-Approved Drugs Being Re-Purposed for COVID-19 Treatment

According to the National Institutes of Health’s Center National Center for Advancing Translational Sciences, many drugs approved for other uses already have been tested in humans, so detailed information is available on their pharmacology, formulation, and potential toxicity.

Therefore, trying a Food and Drug Administration (FDA)-approved drug for one disease as a new therapy for an unrelated disease could allow the treatment to be ready for clinical trials more quickly thus speeding the FDA’s review and, if approved, its integration into health care.¹ This is more commonly referred to as “drug re-purposing” or “off-label use.”

FDA approval on a repurposed drug can take approximately three to four years as compared to an investigational new drug (IND), which may take greater than 10 years. The approval rate for a repurposed drug in approximately 30 percent¹ whereas an IND is less than 12 percent.²

In an effort to combat the coronavirus (COVID-19), front-line physicians have already repurposed two drugs: hydroxychloroquine (brand name Plaquenil^®—commonly used for malaria and rheumatoid arthritis) and azithromycin (multiple brand names including Zithromax^® Zithromax Tri-Pak^®, Azythromycin Dose Pack^®, Zithromax Z-Pak^® and Zmax^®)—a macrolide antibiotic used to treat common infections of the respiratory system, the ear and the eye.

Both drugs are known to be low-risk ototoxic agents; however, there is no published research about the synergistic ototoxic effects of these drugs in treating COVID-19. At the present time, it is not known if hearing loss and/or tinnitus will be a late onset of this COVID-19 drug intervention. Therefore, case history questions will need to be added to accommodate this new population of patients.

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