Nonobstructive idiopathic feline lower urinary tract disease: How to approach a puzzling disorder - Veterinary Medicine
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Nonobstructive idiopathic feline lower urinary tract disease: How to approach a puzzling disorder
Researchers have yet to pin down the cause or causes of this frustrating and often painful disease, so a definitive treatment protocol remains elusive. Current recommendations include lifestyle changes such as stress relief and increased water intake.



Table 2 Proposed Causes of iFLUTD and Their Respective Treatments and Efficacies
The difficulty of evaluating the efficacy of therapies for iFLUTD is that this disease is self-limiting, resolving within five to 10 days regardless of the therapy used.36 Various therapies addressing each proposed mechanism of action have been investigated, usually in retrospective studies in which many confounding variables had to be considered or in small prospective studies that were not blinded or that did not use controls (Table 2).

Address infections

Theory. Infectious agents, including stealth organisms, are responsible for iFLUTD.

Evidence. Most studies, including those investigating interstitial cystitis in women, indicate little evidence to support an infectious cause of iFLUTD.1,4,6,8 Despite recent reports of increased percentages of UTIs and the identification of novel feline caliciviruses with iFLUTD, further investigation is needed before antimicrobials or antivirals can be recommended (see the discussion regarding causes of iFLUTD).

Bottom line. Do not administer antimicrobials unless the urine bacterial culture results are positive.

Alleviate pain and inflammation

Theory. Pain and inflammation are due to neurogenic stimulation and increases in mast cells and substance P.

Evidence. The efficacy of amitriptyline, nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and antispasmodics in cats with iFLUTD has been investigated.

  • Amitriptyline (2.5 to 10 mg/cat/day given orally37 ): This tricyclic antidepressant is an anticholinergic, antihistamine, anti-alpha-adrenergic, anti-inflammatory, and analgesic. In one study, nine of 15 cats with chronic iFLUTD had decreased clinical signs after amitriptyline administration for 12 months.36 However, in another study in which cats with iFLUTD received either a placebo or amitriptyline for seven days, no differences in clinical signs between the two groups were found.38 This finding was also confirmed in a separate study of short-term amitriptyline use.39 The disappointing results in these studies may have been due to the short-term drug administration. Amitriptyline can cause somnolence, decreased grooming, and weight gain.36

  • NSAIDS: Piroxicam and meloxicam have been used in cats with LUTS with some anecdotal success, but no controlled prospective studies have been performed.5,40 Before using any NSAID, make sure the patient's hydration status and renal function are adequate. I cannot make recommendations about their safe and effective use in cats with iFLUTD because controlled studies are lacking.

  • Glucocorticoids: A double-blind clinical study in cats with iFLUTD showed no difference in clinical signs or recurrence in control cats vs. those receiving glucocorticoids.41 Thus, glucocorticoid administration is not recommended, especially if NSAIDs are being administered concurrently.

  • Antispasmodics (e.g. diazepam, dantrolene, phenoxybenzamine, propantheline, acepromazine): Limited studies in cats with iFLUTD have shown some relief with a few of these drugs in the treatment of urethral smooth muscle and skeletal muscle spasms. Because of possible side effects and a lack of studies in cats with iFLUTD for each drug, no single agent can be recommended.5,40

Bottom line. Amitriptyline may be useful when given long-term in chronic, recurrent cases but is not helpful in acute episodes.


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