ENROFLOXACIN AND URINARY CRYSTALS

We periodically receive questions about the urinary crystals that can be produced with the use of enrofloxacin. Two chief questions are generally asked.

1. Might enrofloxacin contribute to the development of struvite crystals and thus exacerbate Feline Lower Urinary Tract Disease (Idiopathic Cystitis)?
   
   The answer is probably not. The urinary crystals that have been associated with feline lower urinary tract disease are generally struvite or oxalate crystals, not crystals made out of enrofloxacin. Further, the relationship between crystals and feline lower urinary tract disease is controversial as are the assorted treatments commonly prescribed for the symptoms of this condition. There is simply no universally accepted treatment for this condition and the condition is felt to have many possible causes. Enrofloxacin crystals are an unusual finding and it is unknown how they might fit into this syndrome were they to occur in a given patient.
   
   
2. What references do we have that enrofloxacin causes urinary crystals?
   
   Not only is it possible for enrofloxacin to form crystals; entire bladder stones have been formed out of enrofloxacin, rare as this might be. Granted, a urinary stone composed of enrofloxacin is very unusual but it is important to realize that enrofloxacin crystals might be found in a urine sample of a patient on enrofloxacin and that these crystals should be recognized as such and not confused with more common/relevant urinary crystals.

Iatrogenic Disorders of the Urinary Tract--Treating our Treatments.
ACVIM 1999, C.A. Osborne, D.J. Polzin, J. P. Lulich, S.J. Ross, F. Jacob, A. C. O'Keefe.

Pharmacologic Treatment of Uroliths -- Cause or Cure.
ACVIM 1998, C. Osborne, J. Lulich, et. al.

Drug-Induced Urolithiasis
Osborne, C.A., Lulich, J.P., Bartges, J.W. et al.
Veterinary Clinics of North America Small Animal Practice 29[1]:251-66, xiv 1999 Jan.

Page last reviewed: 10/16/2021