Ototoxicity of Vancomycin and Analogues

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.

Glycopeptide Hypersensitivity and Adverse Reactions

Glycopeptides, such as vancomycin and teicoplanin, are primarily used in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections, such as cellulitis, endocarditis, meningitis, pneumonia, and septicemia, and are some of the most commonly prescribed parenteral antimicrobials. Parenteral glycopeptides are first-line therapy for severe MRSA infections; however, oral vancomycin is used as a first-line treatment of Clostridioides difficile infections. Also, we currently have the longer-acting lipoglycopeptides, such as dalbavancin, oritavancin, and telavancin to our armamentarium for the treatment of MRSA infections. Lastly, vancomycin is often used as an alternative treatment for patients with β-lactam hypersensitivity. Common adverse effects associated with glycopeptide use include nephrotoxicity, ototoxicity, and Redman Syndrome (RMS). The RMS is often mistaken for a true allergy; however, it is a histamine-related infusion reaction rather than a true immunoglobulin E (IgE)-mediated allergic reaction. Although hypersensitivity to glycopeptides is rare, both immune-mediated and delayed reactions have been reported in the literature. We describe the various types of glycopeptide hypersensitivity reactions associated with glycopeptides and lipoglycopeptides, including IgE-mediated reactions, RMS, and linear immunoglobulin A bullous dermatosis, as well as describe cross-reactivity with other glycopeptides.

The antibiotic vancomycin induces complexation and aggregation of gastrointestinal and submaxillary mucins

Vancomycin, a branched tricyclic glycosylated peptide antibiotic, is a last-line defence against serious infections caused by staphylococci, enterococci and other Gram-positive bacteria. Orally-administered vancomycin is the drug of choice to treat pseudomembranous enterocolitis in the gastrointestinal tract. However, the risk of vancomycin-resistant enterococcal infection or colonization is significantly associated with oral vancomycin. Using the powerful matrix-free assay of co-sedimentation analytical ultracentrifugation, reinforced by dynamic light scattering and environmental scanning electron microscopy, and with porcine mucin as the model mucin system, this is the first study to demonstrate strong interactions between vancomycin and gastric and intestinal mucins, resulting in very large aggregates and depletion of macromolecular mucin and occurring at concentrations relevant to oral dosing. In the case of another mucin which has a much lower degree of glycosylation (~60%) - bovine submaxillary mucin - a weaker but still demonstrable interaction is observed. Our demonstration - for the first time - of complexation/depletion interactions for model mucin systems with vancomycin provides the basis for further study on the implications of complexation on glycopeptide transit in humans, antibiotic bioavailability for target inhibition, in situ generation of resistance and future development strategies for absorption of the antibiotic across the mucus barrier.

Neurological and Psychiatric Adverse Effects of Antimicrobials

Antimicrobials are a widely used class of medications, but several of them are associated with neurological and psychiatric side effects. The exact incidence of neurotoxicity with anti-infectives is unknown, although it is estimated to be < 1%. Neurotoxicity occurs with all classes of antimicrobials, such as antibiotics, antimycobacterials, antivirals, antifungals and antiretrovirals, with side effects ranging from headaches, anxiety and depression to confusion, delirium, psychosis, mania and seizures, among others. It is important to consider these possible side effects to prevent misdiagnosis or delayed treatment as drug withdrawal can be associated with reversibility in most cases. This article highlights the different neurotoxic effects of a range of antimicrobials, discusses proposed mechanisms of onset and offers general management recommendations. The effects of antibiotics on the gut microbiome and how they may ultimately affect cognition is also briefly examined.

Ototoxicity of cypermethrin in Wistar rats

Introduction

This study presents the effect of cypermethrin on the cochlear function in Wistar rats post-subchronic inhalation exposure. Worldwide several pesticides are described as causing health disorders. Cypermethrin is currently one of the most commonly used, however, little is known about its harmful effects, especially related to hearing. Human studies have associated pesticides with hearing disorders, but they present limited conclusions due to the multiple factors to which the population is exposed, such as noise.

Objective

Mimic human exposure to cypermethrin and to verify the effects on cochlear function.

Methods

It is a subchronic inhalation animal study (6 weeks, 4 hours/day), using 36 male Wistar aged 60 day. Rats were randomly assigned into three groups: Control (12 rats exposed to inhalation of water); Positive Control for auditory lesion (12 rats administrated with 24 mg/kg intraperitoneal cisplatin); Experimental (12 rats exposed to inhalation of cypermethrin – 0.25 mg/L). Animals were evaluated by distortion product otoacoustic emissions pre- and post-exposure.

Results

The frequencies of 8, 10 and 12 kHz in both ears (right p = 0.003; 0.004; 0.008 and left 0.003; 0.016; 0.005 respectively) and at frequencies 4 and 6 in the right ear (p = 0.007 and 0.015, respectively) in the animals exposed to cypermethrin resulted in reduction.

Conclusion

Subchronic inhalation exposure to cypermethrin provided ototoxicity in rats.

Effect of gentamicin and levels of ambient sound on hearing screening outcomes in the neonatal intensive care unit: A pilot study

OBJECTIVE

Hearing loss rates in infants admitted to neonatal intensive care units (NICU) run at 2-15%, compared to 0.3% in full-term births. The etiology of this difference remains poorly understood. We examined whether the level of ambient sound and/or cumulative gentamicin (an aminoglycoside) exposure affect NICU hearing screening results, as either exposure can cause acquired, permanent hearing loss. We hypothesized that higher levels of ambient sound in the NICU, and/or gentamicin dosing, increase the risk of referral on the distortion product otoacoustic emission (DPOAE) assessments and/or automated auditory brainstem response (AABR) screens.

METHODS

This was a prospective pilot outcomes study of 82 infants (<37 weeks gestational age) admitted to the NICU at Oregon Health & Science University. An ER-200D sound pressure level dosimeter was used to collect daily sound exposure in the NICU for each neonate. Gentamicin dosing was also calculated for each infant, including the total daily dose based on body mass (mg/kg/day), as well as the total number of treatment days. DPOAE and AABR assessments were conducted prior to discharge to evaluate hearing status. Exclusion criteria included congenital infections associated with hearing loss, and congenital craniofacial or otologic abnormalities.

RESULTS

The mean level of ambient sound was 62.9 dBA (range 51.8-70.6 dBA), greatly exceeding American Academy of Pediatrics (AAP) recommendation of <45.0 dBA. More than 80% of subjects received gentamicin treatment. The referral rate for (i) AABRs, (frequency range: ∼1000-4000 Hz), was 5%; (ii) DPOAEs with a broad F2 frequency range (2063-10031 Hz) was 39%; (iii) DPOAEs with a low-frequency F2 range (<4172 Hz) was 29%, and (iv) DPOAEs with a high-frequency F2 range (>4172 Hz) was 44%. DPOAE referrals were significantly greater for infants receiving >2 days of gentamicin dosing compared to fewer doses (p = 0.004). The effect of sound exposure and gentamicin treatment on hearing could not be determined due to the low number of NICU infants without gentamicin exposure (for control comparisons).

CONCLUSION

All infants were exposed to higher levels of ambient sound that substantially exceed AAP guidelines. More referrals were generated by DPOAE assessments than with AABR screens, with significantly more DPOAE referrals with a high-frequency F2 range, consistent with sound- and/or gentamicin-induced cochlear dysfunction. Adding higher frequency DPOAE assessments to existing NICU hearing screening protocols could better identify infants at-risk for ototoxicity.

Methadone, another cause of opioid-associated hearing loss: a case report

BACKGROUND

Methadone has been used for many years in the clinical setting and has many well-described side effects. In recent years, the use of methadone and other opioids have been increasing throughout the United States (US), and presentations to US Emergency Departments (EDs) due to opioid use and abuse are increasing as well.

OBJECTIVES

As methadone and opioid use increases, ED physicians should be aware of infrequently seen side effects and toxicities associated with the use of these drugs.

CASE REPORT

We report the case of a previously healthy 20-year-old man who presented with acute onset of bilateral hearing loss secondary to an unintentional methadone overdose. At follow-up, the patient's hearing had returned to normal, with the only intervention being abstinence from methadone.

CONCLUSION

Although bilateral hearing loss is a rare toxic finding of opioid ingestion, given the prevalence of opioid use, this etiology should be considered in any patient presenting with this chief complaint.

Outcomes analysis of daptomycin use in a community hospital

This study was conducted to assess clinical and cost outcomes associated with the use of daptomycin. This objective was addressed through a consecutive patient chart review of the first 50 inpatients treated with daptomycin. Type of infection, identity of isolated pathogens, prior therapy, duration of therapy, length of hospitalization, cost of antibiotics, adverse events, and outcomes were evaluated. The analysis showed that mean patient age was 64 y, and mean length of hospitalization was 9.2 d. A total of 62% of patients had confirmed methicillin-resistant Staphylococcus aureus infection. The mean duration of daptomycin therapy was 7.5 d; however, in patients given treatment for complicated skin and skin structure infections, the mean duration of therapy was 6.1 d (n=15) and 7.1 d (n=16) for first- and second-line daptomycin therapy, respectively. The average course of daptomycin cost $727 (n=38) and $390 (n=11), respectively, in the subset of patients with renal insufficiency. In patients who did not respond to prior antibiotic treatment for a Gram-positive bacterial infection (n=26), the mean duration of prior therapy with antibiotics was 6.0 d and the cost was $287. For patients who were transitioned to outpatient daptomycin therapy (n=14), hospital charges were reduced by an estimated $102,340. In 48 patients (96%), infection was resolved with daptomycin therapy. Daptomycin was effective in resolving Grampositive infection in this aged patient population. Earlier identification of antibiotic failure, first-line use of daptomycin in patients with complicated skin and skin structure infections, and outpatient daptomycin therapy provided cost savings and improved clinical outcomes at this facility.

Vancomycin: a history

Vancomycin became available for clinical use >50 years ago but was soon discarded in favor of other antibiotics that were deemed to be more efficacious and less toxic. The advent of pseudomembranous enterocolitis, coupled with the spread of methicillin-resistant Staphylococcus aureus, led to a resurgence in the use of vancomycin. Almost immediately, concerns arose with regard to its therapeutic utility. In addition, resistance to vancomycin developed, first in enterococci and later in staphylococci. Several types of resistance have now been identified, each with a unique effect on infections treated with vancomycin. Recent studies have rekindled interest in the best way to administer the antibiotic. The findings of future studies may result in a return to measuring levels of vancomycin in serum, to assure a successful therapeutic outcome.

Clinical ototoxicity of teicoplanin

No strong evidence of ototoxicity of teicoplanin can be found in the literature, possibly because of conservative definitions of ototoxicity. We performed audiometry over time to compare the ototoxicity of teicoplanin with that of cloxacillin as a non-ototoxic standard. The data were analyzed with a linear mixed-effects model. The hearing thresholds of 12 patients who were treated with teicoplanin for severe staphylococcal infections showed a slight but significant increase over time, whereas the thresholds of 5 patients treated with cloxacillin decreased significantly during treatment. This improvement in hearing with cloxacillin may be attributed to improvement of the clinical condition. This outcome implies that previous reports that suggest a lack of ototoxicity of teicoplanin potentially underestimate the risk and should be interpreted accordingly.

Vancomycin

This review describes the use of vancomycin in neonates over the last three decades. Given the relation of late-onset neonatal septicaemia to outcome and the increase in coagulase-negative staphylococcal infection as causative organism, vancomycin remains an important antibacterial in the neonatal intensive care unit. The pharmacokinetic behaviour of vancomycin in neonates can be adequately described by a one- or two-compartment model and is mainly determined by postconceptional age and renal function. In neonates, a patent ductus arteriosus as well as treatment with indomethacin or extracorporeal membrane oxygenation (ECMO) leads to an increase in volume of distribution and a decrease in clearance. Microbiological studies in vitro have shown that an increase in vancomycin concentrations above the minimum inhibitory concentration does not result in more effective killing. The microbiological and clinical efficacy of vancomycin in neonates has only been studied explicitly in a restricted number of patients. There are no definitive data relating serum concentrations to effect in this patient group. Vancomycin-related nephrotoxicity and ototoxicity in neonates is rare, and no clear relation to serum concentrations has been demonstrated. Based on the pharmacokinetic profile of vancomycin in neonates, several administration regimens have been constructed. Recent guidelines have suggested that dosage can be independent of gestational age or postconceptional age in neonates without renal failure. In patients with renal failure, therapy can be adequately tailored by using a regimen based on serum creatinine. The usefulness of routine monitoring of peak serum concentrations is doubtful based on the current literature. Recent research demonstrates a shift towards taking only routine trough serum concentrations in order to optimise efficacy. Patients with renal failure and other special subpopulations, such as patients exposed to ECMO or indomethacin, need to be monitored more closely.

Newborn hearing screening: tobramycin and vancomycin are not risk factors for hearing loss

OBJECTIVE

To investigate the chance of detecting hearing loss with neonatal hearing screening in relation to exposure to tobramycin and vancomycin.

STUDY DESIGN

Automated auditory brainstem response (A-ABR) hearing screening was performed in all neonates with at least one risk factor. Data on drug administration were abstracted from patient files. Exposure to these drugs was related to the result of hearing screening. In patients failing hearing screening, exposure to ototoxic medication was assessed in the light of other risk factors for hearing loss.

RESULTS

Six hundred twenty-five patients were analyzed; 45 neonates failed hearing screening. Tobramycin, vancomycin, and furosemide were used in 508, 130, and 174 patients, respectively. Exposure to vancomycin, tobramycin, or furosemide or a combination, defined in terms of treatment duration, total dose, or serum concentrations of antibiotics, was not related to failure to pass A-ABR screening. Ototoxic medication was not the most probable risk factor in any of the patients with serum concentrations outside the therapeutic range.

CONCLUSIONS

Routine therapeutic drug monitoring of vancomycin and tobramycin in neonates for ototoxicity reasons is not helpful in detecting patients at risk for clinically important hearing loss in the 2- to 4-kHz range. A longer period of audiometric follow-up is needed to determine any long-term effects.

Sensorineural hearing loss associated with intrathecal vancomycin

OBJECTIVE

To report a case of nonreversible bilateral sensorineural hearing loss resulting from administration of intrathecal vancomycin.

CASE SUMMARY

A 63-year-old white man with newly diagnosed pre-B-cell acute lymphocytic leukemia developed Corynebacterium jeikeium meningitis associated with an Ommaya reservoir. The patient was treated with intravenous vancomycin for several days without symptomatic improvement, and intrathecal vancomycin was added to the treatment regimen. Difficulty in the patient's hearing was noted after the first intrathecal dose and he experienced complete hearing loss after the second intrathecal dose. An audiogram was performed and the patient was diagnosed with cranial nerve VIII bilateral sensorineural hearing loss. The Ommaya reservoir was removed and the patient was successfully treated with linezolid.

DISCUSSION

Ototoxicity with intravenous vancomycin has been documented in multiple case reports, but this adverse effect has not been reported with intrathecal vancomycin. Cerebrospinal fluid vancomycin concentrations were not measured in our patient, but there was 1 documented occurrence of supratherapeutic serum vancomycin concentrations. Other drug-related causes of ototoxicity were evaluated and intrathecal vancomycin-induced ototoxicity was considered to be possible according to the Naranjo probability scale.

CONCLUSIONS

The strong temporal relationship that was seen in this case suggests the possibility of an association between administration of intrathecal vancomycin and hearing loss. Healthcare providers should consider the potential for this adverse reaction with the intrathecal route of vancomycin administration.

Adverse perinatal conditions and the inner ear

Epidemiological studies in a number of Western countries have attributed 6-14% of sensorineural hearing impairment from birth or early childhood to problems relating to the birth process [1-4]. In spite of this association it is not always clear in individual instances whether adverse perinatal conditions identified subsequently have been causative of a hearing loss or not. It is possible that the hearing impairment was the consequence of an earlier intrauterine insult or is a coincidental finding. Infants carrying genetic mutations for hearing loss may coincidentally experience perinatal stress. It is therefore important to investigate the cause of a hearing loss discovered in infancy irrespective of the history of the infant having experienced adverse conditions surrounding the time of birth.

Hearing loss in critical care: an unappreciated phenomenon

OBJECTIVES

The objectives of this article are to review the physiology of hearing; identify acute pathologic and perceived causes of hearing loss in the adult critically ill patient; and to discuss its evaluation, treatment, and prevention.

DATA SOURCES

Computerized bibliographic search of MEDLINE from 1966 to the present of all relevant articles in all languages on acute hearing loss in the adult population.

DATA EXTRACTION

Data gathered from studies and reports of acute hearing loss as relates or potentially relates to the peri-intensive care unit (ICU) period.

DATA SYNTHESIS

Hearing loss is an infrequent but potentially serious complication associated with critical illness. The causes of hearing loss in the ICU patient include mechanical or accidental trauma, administration of ototoxic medications, local or systemic infections, vascular and hematologic disorders, autoimmune diseases, and environmental noise. Patients who are elderly, have coexisting liver or renal failure, or who are receiving concomitantly administered ototoxic drugs are particularly at risk for developing hearing loss. A thorough assessment of potential causes of hearing loss and audiological examination should be undertaken on all ICU patients suspected of hearing loss. Mechanical, pharmacologic, and environmental strategies are available to decrease the incidence of hearing loss in this patient population.

CONCLUSIONS

Hearing loss should be recognized as a potential clinical problem by intensivists. Its causes should be identified and appropriate evaluation and therapy initiated. High risk populations should be identified for preventive measures.

Vancomycin administration in continuous ambulatory peritoneal dialysis: the risk of ototoxicity

A prospective study was undertaken in 16 patients with chronic renal failure on continuous ambulatory peritoneal dialysis, with 22 episodes of peritonitis treated with vancomycin, a known ototoxic agent. Twelve patients had one episode each, and four had recurrent peritonitis. Each treatment course consisted of two infusions of vancomycin (30 mg/kg body weight) in 2 L of peritoneal dialysate administered at 6-day intervals. Serum vancomycin analyzed by enzyme immunoassay showed a mean trough level of 11.00 microg/ml on day 6 and mean serum levels of 33.8 and 38.6 microg/ml about 12 hours after administration on days 1 and 7, respectively. Similar levels, well within the therapeutic range, were encountered with repeated vancomycin therapy for recurrent episodes of peritonitis, suggesting that no changes occurred in the pharmacokinetic profile of the drug. Pure-tone audiometry, electronystagmography, and clinical assessment performed during each course of treatment showed no evidence of ototoxicity even on repeated courses of vancomycin therapy. The results suggest that vancomycin therapy when given in appropriate concentrations as a single therapeutic agent is both effective and safe. We believe, however, that vancomycin administered in combination with an aminoglycoside may produce ototoxic effects that may be greatly aggravated, possibly because of synergism.

Acute massive gentamicin intoxication in a patient with end-stage renal disease

A 65-year-old man with end-stage renal disease on continuous ambulatory peritoneal dialysis accidentally received an acute massive overdose of gentamicin as a treatment of peritonitis. The patient developed acute vestibular dysfunction and hearing loss following the overdose. His serum gentamicin had reached the extremely toxic level of 220 microg/mL. To remove the gentamicin, the patient received hemodialysis and hemoperfusion immediately. This was followed by two more courses of hemodialysis during the following 2 days. The gentamicin level was brought down to 10 microg/mL after the third hemodialysis. Moderate and persistent high-frequency hearing loss was documented with serial audiograms. The patient made a gradual but incomplete recovery from the vestibular dysfunction. The complications of gentamicin toxicity and its management are discussed with respect to our patient.

Use of vancomycin in high-flux hemodialysis: experience with 130 courses of therapy

Vancomycin is often administered to hemodialysis patients at long dosage intervals because its removal by hemodialysis is considered to be negligible. We and others, however, have demonstrated significant removal of vancomycin by high-flux hemodialysis. This report describes our experience with 89 courses of vancomycin using a revised regimen with a loading dose followed by 500 mg doses after each dialysis treatment, and compares results with 41 courses using single weekly dosing. All patients were dialyzed with high-flux membranes using volumetric ultrafiltration and bicarbonate dialysate. Serum vancomycin levels were obtained two hours after completion of infusion (peak) and immediately prior to dialysis (trough) and were measured by Abbot TDx fluorescence polarization immunoassay. Duration of multiple-dose therapy was 11 +/- 8 days, with mean total dose 3.6 +/- 1.8 g. Initial doses of 20 mg/kg rapidly and reliably established therapeutic pre-dialysis serum levels (10 to 25 micrograms/ml). In patients treated with multiple dosing 431 pre-dialysis levels were obtained. The mean level was 15.9 +/- 5.7 micrograms/ml; 55 levels (13%) were less than 10 micrograms/ml and 22 (5%) were above 25 micrograms/ml. In patients treated once weekly, 77% of levels were below 10 micrograms/ml by five days after administration, and 84% at one week. No patient developed demonstrable ototoxicity. Twenty-five patients were treated for > or = two weeks, five for > or = four weeks, and two for > five weeks, with no evidence of toxic accumulation. Mean peak level was 20.1 +/- 4.6 micrograms/ml, with a mean difference from preceding pre-dialysis level of 7.2 +/- 2.2 micrograms/ml. We conclude that in high-flux hemodialysis, a 20 mg/kg loading dose of vancomycin followed by 500 mg doses after each dialysis treatment achieves predictable, adequate and safe therapeutic levels, does not lead to unacceptably high peaks, and does not accumulate during long treatment courses. By contrast, once-weekly vancomycin dosing resulted in subtherapeutic serum levels after five to seven days, and should be abandoned in the high-flux setting.