title: Gentamicin ototoxicity: a 23-year selected  case series of 103 patients.
abstract: OBJECTIVE
  To review patients with severe bilateral vestibular loss associated with gentamicin treatment in hospital.
  
  
  METHODS
  A retrospective case series of presentations to a balance disorders clinic between 1988 and 2010.
  
  
  METHODS
  Relationship between vestibulotoxicity and gentamicin dose or dosing profile; indications for prescribing gentamicin.
  
  
  RESULTS
  103 patients (age, 18-84 years; mean, 64 years) presented with imbalance, oscillopsia or both, but none had vertigo. Only three noted some hearing impairment after having gentamicin, but audiometric thresholds for all patients were consistent with their age. In all patients, the following tests gave positive results: a bilateral clinical head-impulse test, a vertical head-shaking test for vertical oscillopsia, and a foam Romberg test. In 21 patients, imbalance occurred during gentamicin treatment (ignored or dismissed by prescribers in 20) and in 66 after treatment; the remaining 16 could not recall when symptoms were first noticed, except that it was after gentamicin treatment in hospital. Total gentamicin dose range was 2-318 mg/kg (mean, 52 mg/kg), daily dose range was 1.5-5.6 mg/kg (mean, 3.5mg/kg), and duration was 1-80 days (mean, 17 days). Six patients had only a single dose; 26 had five or fewer doses. Serum gentamicin levels, measured in 82 patients, were in the recommended range in 59. Time to diagnosis ranged from 4 days to 15 years. Nephrotoxicity developed in 43 patients. Gentamicin dosage complied with contemporary or current Australian antibiotic guidelines in under half the patients.
  
  
  CONCLUSIONS
  Gentamicin ototoxicity is vestibular, not cochlear, producing permanent loss of balance, but not of hearing. Gentamicin can be vestibulotoxic in any dose, in any regimen, at any serum level.
authors.affiliation: Department of Neurology, Royal Prince Alfred Hospital, Sydney, NSW.
authors.forename: Rebekah M
authors.initials: RM
authors.lastname: Ahmed
authors.forename: Imelda P
authors.initials: IP
authors.lastname: Hannigan
authors.forename: Hamish G
authors.initials: HG
authors.lastname: MacDougall
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Chan
authors.forename: G Michael
authors.initials: GM
authors.lastname: Halmagyi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001315:Australia / Q000453:epidemiology; D057210:Delayed Diagnosis; D004305:Dose-Response Relationship, Drug; D005260:Female; D005839:Gentamicins / Q000009:adverse effects*; D019983:Guideline Adherence; D006801:Humans; D007674:Kidney Diseases / Q000139:chemically induced / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D015837:Vestibular Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins