Retinal safety of a new fluoroquinolone, pradofloxacin, in cats: assessment with electroretinography.
OBJECTIVE
To investigate the safety of a new fluoroquinolone, pradofloxacin, on the cat retina using electroretinogram.


METHODS
Ganzfeld ERGs were recorded in 40 cats treated orally for 23 days in 4 groups: CTRL (n = 9): placebo-vehicle; PRADO30 (n = 10): pradofloxacin 30 mg/kg/day; PRADO50 (n = 14): pradofloxacin 50 mg/kg/day; and ENRO30 (n = 7): enrofloxacin at toxic doses of 30 mg/kg/day. ERG was performed before treatment and once weekly during the treatment period. An extended ISCEV protocol with addition of 8 steps of increasing luminance in dark adapted condition was carried out to assess: V (max) (saturated scotopic b-wave amplitude) and k (luminance inducing V (max)/2). OCT and retinal histological changes were also investigated.


RESULTS
Pradofloxacin showed no effects in respect to rod b-wave, V (max), k and maximum scotopic a-wave (P > 0.05). Oscillatory potentials, cone ERG and flicker were also unaltered (P > 0.05). Rod b-wave was undetectable after treatment in ENRO30 group, V (max) was reduced to 10.5% of the baseline (P < 0.05), accompanied by an increase of k by 1 log cd s/m(2) (P < 0.05). Oscillatory potentials, cone b-wave amplitude and 30 Hz flicker amplitude were reduced to 8.3%, 58.9% and 37.4% of the baseline, respectively (P < 0.05). Effects were also seen in OCT and retinal histology starting within one week after the start of treatment and thereafter remaining stable.


CONCLUSIONS
Pradofloxacin at 6 and 10 times the recommended doses was shown to have no retinal toxic effects in cats, neither on rod or cone function with ERG.
Messias
Andre
A
Center for Ophthalmology, University of Tübingen, Schleichstrasse 12-16, 72076, Tubingen, Germany. amessias@hotmail.com
Gekeler
Florian
F
Wegener
Alfred
A
Dietz
Klaus
K
Kohler
Konrad
K
Zrenner
Eberhart
E
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D002415:Cats; D003623:Dark Adaptation; D004596:Electroretinography / Q000187:drug effects*; D005260:Female; D024841:Fluoroquinolones / Q000633:toxicity*; D008297:Male; D009991:Oscillometry; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects; D012160:Retina / Q000187:drug effects* / Q000473:pathology; D041623:Tomography, Optical Coherence
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; C507250:pradofloxacin