Risk of sudden sensorineural hearing loss in adults using phosphodiesterase type 5 inhibitors: Population-based cohort study

Phosphodiesterase-5 (PDE-5) Inhibitors and Ototoxicity: A Systematic Review

OBJECTIVE

This study explores the current literature regarding associations between phosphodiesterase-5 (PDE-5) inhibitors and ototoxicity and provides a detailed summary and discussion of the findings.

DATA SOURCES

A comprehensive electronic search of PubMed/MEDLINE, Scopus, and Cochrane Library for studies published from database inception through March 21, 2018.

STUDY SELECTION

Basic science articles, epidemiological studies, randomized controlled trials, cohort studies, case reports, reviews, meta-analyses, press releases, and newsletters were included. The PRISMA search strategy was used to select papers. Search terms are included in the appendix (http://links.lww.com/MAO/A733).

RESULTS

Twenty-two articles met the inclusion criteria. Among case reports, there were a total of nine patients, all male, with an average age of 57.4 years (37-79 years, SD = 13.87 years). Of the cases of hearing loss, 25% (2/8 cases) were bilateral and 75% (6/8) were unilateral; 22% (2/9) were associated with tinnitus; and 33% (3/9) had accompanying vestibular symptoms (including vertigo and dizziness). Among multipatient studies, all prospective studies failed to find a significant association between ototoxicity and PDE-5 inhibitor use. Results of the retrospective studies were also heterogeneous. Many key molecules in the PDE-5 inhibition pathway have been demonstrated to exist in the cochlea. However, mirroring the clinical studies, the basic science mechanisms have suggested both ototoxic and otoprotective effects.

CONCLUSIONS

Currently, the literature is inconclusive regarding the interaction between PDE-5 inhibitor use and ototoxicity. Future study such as a double-blinded placebo controlled randomized trial with audiometric assessment would provide more sound evidence. Similarly, a unified molecular model is necessary.

Predicting the Need for a Tier II Ototoxicity Study From Early Renal Function Data

History has established that many drugs, such as the antibiotics, chemotherapies, and loop diuretics, are capable of inducing both nephrotoxicity and ototoxicity. The exact mechanisms by which cellular damage occurs remain to be fully elucidated. Monitoring the indices of renal function conducted in the Food and Drug Administration's prescribed set of early investigational new drug (IND)-enabling studies may be the first signs of ototoxicity properties of the new drug candidate. In developing improved and efficacious new molecular entities, it is critically necessary to understand the cellular and molecular mechanisms underlying the potential ototoxic effects as early in the drug development program as possible. Elucidation of these mechanisms will facilitate the development of safe and effective clinical approaches for the prevention and amelioration of drug-induced ototoxicity prior to the first dose in man. Biomarkers for nephrotoxicity in early tier I or tier II nonclinical IND-enabling studies should raise an inquiry as to the need to conduct a full auditory function assay early in the game to clear the pipeline with a safer candidate that has a higher probability of continued therapeutic compliance once approved for distribution.