Controversies in Management of FLUTD/UO Cats

Feline lower urinary tract disease (FLUTD) and urethral obstruction remain among the most common—and debated—emergencies in small animal practice. While stabilization, relief of obstruction, and supportive care are well established, several aspects of medical management continue to generate controversy such as the use of NSAIDs, the use of antimicrobials and the use of prazosin.
 

Pain control is a cornerstone of therapy, yet the role of NSAIDs in obstructed cats is nuanced. These patients often present with varying degrees of dehydration, electrolyte derangements and likely renal compromise resulting in azotemia. Because NSAIDs can reduce renal perfusion—especially in the setting of hypovolemia—their use in the acute phase is generally discouraged. Most clinicians prioritize opioids (e.g., buprenorphine, methadone) during initial stabilization. However, once the patient is rehydrated, hemodynamically stable, and azotemia is improving, some veterinarians consider short-term NSAID use to address inflammation and discomfort. Evidence supporting this practice has not found improvement in signs with administration of an NSAID. One study found that there was no difference in the recurrence rate in cats that used an NSAID (meloxicam) vs those that did not³. There was also no difference in perceived comfort or voiding in-hospital or at home between the two groups³.  Another source that evaluated three randomized controlled trials and a single retrospective cohort study failed to find a significant association between the use of glucocorticoids or NSAIDs with severity of FLUTD clinical signs or risk of reobstruction. Their conclusion was “There is insufficient evidence to recommend the use of either drug category in decreasing time to resolution or severity of clinical signs in cases of idiopathic FLUTD or FIC.”⁶ 
 

Opinions on this vary even at our hospital though the majority of clinicians avoid the use of NSAIDs in either obstructed or FLUTD cats due to the potential renal compromise. Even in FLUTD cats the risk of obstruction is so great that we try to avoid NSAIDs so as not to give the kidneys a “double whammy”. Instead, we will give an anti-inflammatory dose of steroids to these cats if necessary but do not tend to send home a steroid taper. 
 

Antibiotic stewardship is another area where older practices are being challenged. Historically, many cats with urethral obstruction were discharged with antibiotics as a precaution. However, the overwhelming current evidence suggests that bacterial urinary tract infections are uncommon (<2%) in young to middle-aged cats with FLUTD or urethral obstruction⁴. Routine empirical antibiotic use in these cases is increasingly viewed as unnecessary and potentially harmful, contributing to antimicrobial resistance and altering normal GI flora. Since these cats are very unlikely to have a UTI it is often unnecessary to perform a urine culture². Exceptions to this would include patients with risk factors such as recent catheterization, history of PU surgery, immunosuppression or diabetes, though even in these cases culture-based selection is preferred. 
 

NB: The incidence of UTI does increase in cats >10 years old and in female cats of any age so more routine antibiotic use for these cases could be considered and cultures should be submitted in these instances.
 

Another debated therapy is the use of prazosin, an alpha1 adrenergic antagonist intended to reduce urethral smooth muscle tone. Early rationale for prazosin centered on theoretical relief of urethral spasm and decreased recurrence of obstruction, but clinical evidence has been variable. This medication acts on to relax smooth muscle but in male cats only the proximal ¼-1/3 of the urethra is comprised of smooth muscle; the distal urethra is skeletal muscle and that is where the vast majority of obstructions occur. Prospective, doubleblind trials found no significant reduction in recurrent obstruction in cats treated with prazosin versus placebo after an obstruction episode. A larger observational study even suggested a higher rate of recurrent urethral obstruction in cats treated with prazosin¹. Review of the literature concludes that evidence supporting prazosin to prevent recurrence is weak and that routine use cannot be confidently recommended at this time.
 

Ultimately, management of FLUTD and urethral obstruction can be nuanced but decisions should be made with a lot of thought and consideration of the ever-evolving nature of medicine. 

Works Cited:

¹Conway DS, Rozanski EA, Wayne AS. Prazosin administration increases the rate of recurrent urethral obstruction in cats: 388 cases. J Am Vet Med Assoc. 2022 May 21;260(S2):S7-S11. doi: 10.2460/javma.21.10.0469. PMID: 35290210.

²Cooper, E.S. (2015), Controversies in the management of feline urethral obstruction. Journal of Veterinary Emergency and Critical Care, 25: 130-137. https://doi.org/10.1111/vec.12278

³Dorsch R, Zellner F, Schulz B, Sauter-Louis C, Hartmann K. Evaluation of meloxicam for the treatment of obstructive feline idiopathic cystitis. J Feline Med Surg. 2016 Nov;18(11):925-933. doi: 10.1177/1098612X15621603. Epub 2016 Jul 10. PMID: 26672127; PMCID: PMC11132225.

⁴Kruger, John M., et al. "Clinical evaluation of cats with lower urinary tract disease." Journal of the American Veterinary Medical Association 199.2 (1991): 211-216.

⁵Reineke, E.L., Thomas, E.K., Syring, R.S., Savini, J. and Drobatz, K.J. (2017), The effect of prazosin on outcome in feline urethral obstruction. Journal of Veterinary Emergency and Critical Care, 27: 387-396. https://doi.org/10.1111/vec.12611

⁶Sofyan, L. M. (2021). Are glucocorticoids or NSAIDs more effective in reducing idiopathic feline urinary tract disease signs than no treatment or placebo?. Veterinary Evidence, 6(3). https://doi.org/10.18849/ve.v6i3.439