Inhibitory effect of erythromycin on ion transport by stria vascularis and vestibular dark cells

Ototoxicity of Non-aminoglycoside Antibiotics

It is well-known that aminoglycoside antibiotics can cause significant hearing loss and vestibular deficits that have been described in animal studies and in clinical reports. The purpose of this review is to summarize relevant preclinical and clinical publications that discuss the ototoxicity of non-aminoglycoside antibiotics. The major classes of antibiotics other than aminoglycosides that have been associated with hearing loss in animal studies and in patients are discussed in this report. These antibiotics include: capreomycin, a polypeptide antibiotic that has been used to treat patients with drug-resistant tuberculosis, particularly in developing nations; the macrolides, including erythromycin, azithromycin and clarithromycin; and vancomycin. These antibiotics have been associated with ototoxicity, particularly in neonates. It is critical to be aware of the ototoxic potential of these antibiotics since so much attention has been given to the ototoxicity of aminoglycoside antibiotics in the literature.

Drug-Induced Ototoxicity: A Comprehensive Review and Reference Guide

OBJECTIVE

In an era of increasing polypharmacy, adverse drug effects such as ototoxicity have significant public health implications. Despite the availability of evidence, many health care professionals may not know the risk of ototoxicity in common medications. Therefore, the aim of this review is to provide a comprehensive, easy to use, ototoxic profile of medications with an assessment of supporting evidence.

METHODS

Medications of interest were identified through adverse drug reaction reports derived from Micromedex (IBM), Lexicomp (Wolters Kluwer), and the textbook, Drug Induced Diseases: Prevention, Detection, and Management. Additional evidence was identified though a query of PubMed and the Cochrane database. Evidence of causality was graded according to the following: A (randomized, controlled clinical trials), B (nonrandomized clinical trials, prospective observational studies, cohort studies, retrospective studies, case-controlled studies, and/or postmarketing surveillance studies), and C (case reports/case series).

RESULTS

A total of 194 systemically administered medications associated with ototoxicity were identified, most commonly antimicrobials (53), psychotropics (21), antihypertensive/antiarrhythmics (19), nonsteroidal antiinflammatory drugs (18), and antineoplastics (16). There was evidence of cochleotoxicity in 165 medications (evidence grading A [22], B [77], C [69]), vestibulotoxicity in 100 medications (evidence grading A [23], B [47], and C [30]), and dizziness in 142 medications (evidence grading A [50], B [76], and C [16]). In addition, a review of the evidence of ototoxicity in ototopical medications is also reviewed.

CONCLUSION

The effect and severity of ototoxicity can vary immensely depending on pharmacological and individual patient risk factors. The intent of this comprehensive review was to help health care providers of all sectors obtain a deeper knowledge of drug-induced ototoxicity to make more informed management decisions for their patients.

Drug-induced hearing loss: a case/non-case study in the French pharmacovigilance database

Hearing loss is defined as a decrease in the ability to perceive sounds which can occur suddenly or gradually and affects one ear or both. It is related to various etiologies, in particular drugs. The identification of all drugs that could be associated with hearing loss is essential for the patients' life quality. The objective of our study was to identify signals of hearing loss involving drugs approved in the last 20 years. The occurrence in association with drugs known for their ototoxicity was also analyzed. We used a case/non-case method in the French Pharmacovigilance Database (FPVD). The cases were reports of hearing loss in the FPVD between January 2007 and August 2017. Non-cases were all reports over the same period. We calculated the reporting odds ratio (ROR) with 95% confidence intervals. Among the 555 reports of hearing loss, significant RORs were found for 68 drugs. The main therapeutic classes implicated were antineoplastic agents (n = 240), systemic anti-infective agents (n = 182), immunosuppressants (n = 42) loop diuretics (n = 26), and salicylate analgesics (n = 26). We found signals of hearing loss with azacitidine, vaccines and nevirapine, immunosuppressants such as leflunomide, and biotherapies such as panitumumab and vandetanib. Prescribers should be informed about the potential associations with all these drugs. The role of the pathology itself and the known ototoxic drugs that can be associated do not allow to conclude definitively. Audiograms for the early detection of hearing loss induced by drugs known to be ototoxic are rarely carried out. Preventive treatments exist and must be considered.

Consumption of betel quid contributes to sensorineural hearing impairment through arecoline-induced oxidative stress

Betel quid is one of the most widely used psychoactive substances, and is consumed by approximately 10% of the world’s population. In addition to its carcinogenicity, betel quid has also been reported to affect many organs, including the brain, heart, lungs, gastrointestinal tract, and reproductive organs. As betel quid contains several neurotoxic ingredients, we hypothesize that it also possesses ototoxicity and may lead to sensorineural hearing impairment (SNHI). In this study, we investigated the contribution of betel quid consumption to SNHI in a large clinical cohort, and validated the pathogenetic mechanisms in ex vivo tissue explants. We enrolled a total of 2364 volunteers, and determined their audiologic results based on Z-scores converted from their original frequency-specific hearing thresholds. Using generalized linear regression, we identified a positive correlation between betel quid consumption and the Z-scores across different frequencies. Subsequently, we explored the toxicity of arecoline, the main neuroactive component of betel quid, on tissue explants from murine cochleae. Arecoline reduced cell activity in the explant cultures and induced apoptosis in the hair cells, probably through the effects of oxidative stress. These findings have expanded the potential hazards of betel quid to common neurological disorders, and provide insights into preventive strategies against SNHI caused by neurotoxic substances.

Does Clarithromycin Cause Hearing Loss? A 12-Year Review of Clarithromycin Therapy for Nontuberculous Mycobacterial Lymphadenitis in Children

OBJECTIVE(S)

The objective was to describe the characteristics of hearing losses documented in patients treated with clarithromycin alone for nontuberculous mycobacterial NTM lymphadenitis in a pediatric tertiary care center over a 12-year period.

METHODS

An institutional review board (IRB) approval was obtained. A database search was performed using the ICD-10 diagnosis codes 31.0, 31.1, and 31.8 between January 2004 and January 2017. A REDCap database was created to record variables. Patients were included if they received clarithromycin alone and had, at the minimum, a baseline audiology assessment, and 1 further evaluation during treatment. Fisher's exact test was used to analyze categorical variables, and Wilcoxon rank sum test was used to analyze continuous variables.

RESULTS

A total of 167 patients with cervicofacial NTM were identified. Of them, 42 patients fulfilled inclusion criteria. Three children (7%) developed a hearing loss (HL) between 25 and 63 days after starting treatment. HL was unilateral in 2 children. HL persisted in 1 child following cessation of treatment. However, this patient had Rubinstein Taybi syndrome, limiting our ability to attribute the HL solely to clarithromycin.

CONCLUSION

We noted a 7% hearing loss rate in our series. Confounding issues, such as 1 patient with a syndrome potentially contributing to HL, and limitations to this study, including retrospective design and loss to follow-up, temper our ability to conclude that clarithromycin was the sole cause of these HL. However, enough supporting data for a role in clarithromycin causing HL exist that testing should be considered for patients undergoing long-term clarithromycin treatment.

Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice

Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K+ circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.

Drug-induced ototoxicity: Mechanisms, Pharmacogenetics, and protective strategies

Drug ototoxicity limits the quality of life of patients after treatment, having serious consequences, especially for psychosocial development of children. Although the ototoxicity of many drugs resolves after treatment discontinuation, the use of platinum derivatives and aminoglycosides is associated with permanent hearing loss. In this review, we have listed ototoxic drugs and the mechanisms by which they damage the ears. Moreover, possible protective strategies and important methods for early detection of ototoxic effects are discussed.

Drug-related nephrotoxic and ototoxic reactions : a link through a predictive mechanistic commonality

BACKGROUND

Drug-induced ototoxicity is a subject of interest because many diseases are treated with drugs that have potential toxic effects on the ear. There is evidence that both inner ear and kidney tissue are immunologically, biochemically and functionally related. It has been suggested that drugs that influence the transport of sodium and/or potassium change ionic homeostasis in the inner ear and, hence, induce functional disturbances such as hearing loss, tinnitus and vertigo.

OBJECTIVES

To assess whether renal suspected adverse drug reactions (sADRs) have predictive value for ear and labyrinth adverse drug reactions (ADRs) and whether drug classes involved have influence ion transport systems.

STUDY DESIGN

Data were obtained from the Netherlands Pharmacovigilance Centre Lareb. The study base comprised all reports of sADRs up until 1 January 2007. Cases were all sADRs for relevant renal disorders and all sADRs for relevant ear disorders. All other reported sADRs were selected as 'non-cases'. The relationship between drug classes and renal, ear and labyrinth sADRs was evaluated by calculating reporting odds ratios (RORs). An ROR > or = 1.50 was regarded as a cut-off value for an association. Drug classes were classified into four groups: (A) ROR kidney <1.50 and ROR ear <1.50 or no reports on ear sADRs (reference group); (B) ROR kidney <1.50 and ROR ear > or = 1.50; (C) ROR kidney > or = 1.50 and ROR ear <1.50 or no reports on ear sADRs; and (D) ROR kidney > or = 1.50 and ROR ear > or = 1.50. For each group, we calculated odds ratios (ORs) for the association between the group classification and the effect on ion channels/ion transport systems in kidney and ear tissues.

RESULTS

Of 193 drug classes with relevant ADRs for renal disorders, 120 drug classes also had reports on ototoxic reactions. Fourteen out of 120 drug classes had an ROR > or = 1.50 for the association between the drug class and both renal and ear sADRs. Among these drug classes were several with a well known ability to induce renal (adverse) effects and ear and labyrinth disorders, such as loop diuretics, aminoglycosides and quinine. We found that one mechanistic commonality of the drug classes mentioned in the reports was the ability to affect ion transport systems. The percentage of drugs having this property differed between the four groups. The ORs for groups D and B were significantly higher compared with the reference group (OR 12.2, 95% CI 3.0, 30.5 and OR 8.7, 95% CI 2.4, 18.7, respectively), whereas there was no association for group C.

CONCLUSION

Our data suggest that renal sADRs as such are not a marker for drug-induced ear and labyrinth disorders. However, the ability of drugs to act on ion channels or ion transport systems and, therefore, have an influence on ionic homeostasis in the kidney and ear might be a predictor for the possible occurrence of drug-related ototoxicity.

Sudden hearing loss associated with tacrolimus in a kidney-pancreas allograft recipient

A 38-year-old woman with type 1 diabetes underwent kidney-pancreas transplantation. Her postoperative course was complicated due to recurrent acute graft rejections and pancreatitis. After initial immunosuppression with microemulsion cyclosporine, mycophenolate mofetil, and prednisone with muromonab-CD3 induction, cyclosporine was switched to tacrolimus on day 44. The initial dosage was 5 mg twice/day, but it was gradually increased to 10 mg twice/day, aiming at 15-20 ng/ml. On day 17 of tacrolimus therapy the woman developed sudden hearing loss with tinnitus. The serum tacrolimus level was 28.3 ng/ml (therapeutic range 10-20 ng/ml) on day 20 of tacrolimus therapy, and peaked at 34.9 ng/ml on day 28. Two audiograms performed on days 28 and 29 confirmed bilateral hearing loss of 80% for speech perception, characterized as mild to moderate sensorineural hearing loss with speech reception threshold of 35 dB (normal < 20 dB) in both ears. The tacrolimus dosage was gradually reduced to 6 mg twice/day by day 36, with drug level 9.7 ng/ml, after which her hearing gradually recovered.

Ototoxic effect of erythromycin on cochlear potentials in the guinea pig

The mechanism of hearing loss due to the administration of intravenous erythromycin was investigated in the albino guinea pig, and it was found for the first time that this drug causes cochlear dysfunction. The endocochlear potential (EP) and the cochlear microphonics (CM) recorded at the first cochlear turn transiently decreased when erythromycin was administered intravenously at dosages of 100 and 150 mg/kg. The averaged maximum decrease in EP was 16 mV (n = 5) and 33 mV (n = 5) for 100 and 150 mg/kg, respectively. The maximum decrease in the CM was about 25% when the EP reached its lowest value with the injection of 150 mg/kg. A complete recovery of the EP and CM ensured within 20 minutes after each erythromycin dose. The perilymphatic perfusion of 3 mmol/L of erythromycin decreased the EP and CM; however, in contrast to the intravenous administration, the decrease of the CM was nearly complete and both the EP and CM were irreversible. Hearing loss due to intravenously administered erythromycin could likely be attributle to the transient dysfunction of the stria vascularis, although concomitant dysfunction of the central auditory pathway cannot be excluded.