Felis ISSN 2398-2950

Retina: fluoroquinolone retinopathy

Synonym(s): Fluoroquinolone-induced retinal degeneration / Fluoroquinolone toxicity, enrofloxacin toxicity, Baytril blindness

Contributor(s): Natasha Mitchell, David Gould

Introduction

  • Cause: enrofloxacin administered at a systemic dose above the manufacturer's current dose recommendation can induce a toxic retinopathy.
  • Signs: blindness.
  • Diagnosis: history of systemic enrofloxacin administration at above the manufacturer's current dose recommendation during the preceeding three days.
  • Treatment: withdrawal from enrofloxacin medication.
  • Prognosis: retinal degeneration is permanent. In some cases, milder doses result in reduced vision but not blindness.

Pathogenesis

Pathophysiology

  • A molecular basis for susceptibility to the drug's effects has been documented in cats.
  • The ABCG2 transporter protein normally functions to restrict distribution of fluoroquinolones across the blood-retinal barrier.
  • Feline ABCG2 has been shown to be defective which is thought to allow for the potential build-up of photoactive and potentially retinotoxic fluoroquinolones within the retina.

Timecourse

  • In experimental studies, ophthalmoscopic signs were visible by day 3, and progressive retinal degeneration over the first week can be observed with retinal blood vessel attenuation and tapetal hyperreflectivity.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gelatt K N, Van Der Woerdt A, Ketring K L et al (2011) Enrofloxacin‐associated retinal degeneration in cats. Vet Ophthalmol (2), 99-106 PubMed.
  • Ramirez C J, Minch J D, Gay J M et al (2011) Molecular genetic basis for fluoroquinolone-induced retinal degeneration in cats. Pharmacogenetics and Genomics 21 (2), 66-75 PubMed.
  • Messias A, Gekeler F, Wegener A et al (2008) Retinal safety of a new fluoroquinolone, pradofloxacin, in cats: assessment with electroretinography. Doc Ophthalmol 116 (3), 177-191 PubMed.
  • Ford M M, Dubielzig R R, Giuliano E A et al (2007) Ocular and systemic manifestations after oral administration of a high dose of enrofloxacin in cats. Am J Vet Res 68 (2), 190-202 PubMed.
  • Wiebe V, Hamilton P (2002) Fluoroquinolone-induced retinal degeneration in cats. JAVMA 221 (11), 1568-1571 PubMed.
  • Turnidge J (1999) Pharmacokinetics and pharmacodynamics of fluoroquinolones. Drugs 58 (Suppl 2), 29-36 PubMed.

Other sources of information

  •  Natasha Mitchell & James Oliver (2015) Feline Ophthalmology - The Manual.  Grupo Asis. ISBN 978-84-16315-11-6.


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