REVIEW OF THERAPIES
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).
Table 2 Proposed Causes of iFLUTD and Their Respective Treatments and Efficacies
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.