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46° Congresso Nazionale Multisala SCIVAC
Table 3 Drugs commonly used for feline lower urinary tract disorders Drug
Desired Action
Commonly Used Dose
Amitriptyline (ELAVIL)
Antidepressant, Anticholinergic, Anti-inflammatory, Analgesic
2.5-12.5 mg/cat PO q24 hr
Ammonium chloride (UROEZE)
Urine acidifier
150-300 mg/kg q24 hr- to effect
Bethanacol (URECHOLINE)
Cholinergic agonist
1.25-7.5 mg/cat PO q8 hr
Buspirone (BUSPAR)
Non-benzodiazepine anxiolytic
2.5-7.5 mg/cat PO q12 hr
Dantrolene (DANTRIUM)
Skeletal muscle relaxant
0.5-2 mg/kg q8 hr
Diazepam (VALIUM)
Skeletal muscle relaxant
1-2.5 mg/cat PO q8-12 hr
Dimethylsulfoxide (DMSO; RIMSO-50%)
Anti-inflammatory
10-20 ml 10% DMSO intravesicularly
Hydrochlorthiazide (HYDRODIURIL)
Diuretic-decreases urine calcium
2-4 mg/kg PO q12 hr
Methionine-dl (METHIOGEL; METHIOFORM)
Urine acidifier
1-1.25 g/cat PO q24 hr- to effect
2-MPG (THIOLA)
Anticystinuric
15 mg/kg PO q12 hr
Oxybutin (DITROPAN)
Anticholinergic, Antispasmodic
0.5-1.25 mg/cat PO q8-12 hr
Pentosan polysulfate (ELMIRON)
Glycosaminoglycan
2-10 mg/kg PO q12 hr
Phenoxybenzamine (DIBENZYLINE)
Alpha-adrenergic antagonist
2.5-7.5 mg/cat PO q12-24 hr
Phenylpropanolamine (PROPAGEST; DEXATRIM)
Alpha-adrenergic agonist
1.5-2.2 mg/kg PO q8-12 hr
Piroxicam (FELDINE)
Antiinflammatory
0.3 mg/kg PO q24 hr
Potassium citrate (Polycitra-K; Urocit-K)
Urine alkalinizing agent
40-75 mg/kg PO q12 hr
Prazosin (MINIPRESS)
Alpha-adrenergic antagonist
0.03 mg/kg IV
Prednisolone
Antiinflammatory
0.5-1.0 mg/kg q12 hr
Propantheline (PROBANTHINE)
Anticholinergic
Not established (0.25-0.5 mg/kg PO q12-24 hr)
Glycosaminoglycans Transitional epithelium of the urinary tract is covered by a thin layer of hydrated extracellular macromolecules called glycosaminoglycans (GAGs). Major classes of biologically important GAGs include hyaluronic acid, heparan sulfate, heparin, chondroitin 4-sulfate, chondroitin 6-sulfate, dermatan sulfate, and keratan sulfate. Urothelial GAGs: 1) prevent adherence of microorganisms and crystals to the bladder urothelium, and 2) limit transepithelial movement of urine proteins and other ionic and nonionic solutes. Quantitative or qualitative defects in surface GAGs and subsequent increased urothelial permeability have been hypothesized to be a causative factor in the pathogenesis of feline idiopathic FLUTD and human interstitial cystitis. Oral or intravesicular administration of pentosan polysulfate sodium (ElmironÂŽ), a semi-synthetic low molecular weight heparin GAG analogue, is often used to manage human interstitial cystitis. Pentosan polysulfate reinforced urothelial GAGs and reduced transitional cell injury. Remission of symptoms was observed in 28 to 40% of human interstitial cystitis patients treated with oral or intravesicular pentosan polysulfate compared to only 13 to 20% remission in patients treated with a placebo. Adverse events uncommonly recognized in humans treated with pentosan polysulfate include prolongation of pro-
thrombin time, epistaxis, gingival bleeding, alopecia, abdominal pain, diarrhea, and nausea. The empirical dose extrapolated from human studies is 2 to 10 mg/kg PO q12 hr. However, evaluation of the safety and efficacy of pentosan polysulfate, or other GAG preparations, for treatment of feline idiopathic FLUTD by controlled clinical trials have not yet been reported. Although treatment with drugs designed to restore the GAG lining of the urinary tract is logical, it is not possible to make recommendations at this time.
Urohydrodistention Approximately 30% of human interstitial cystitis patients experience substantial, although temporary, relief of signs following controlled distention of the urinary bladder during anesthesia (therapeutic urohydrodistention). Although exact mechanisms of action of urohydrodistention are unknown, possibilities include 1) increased urothelial glycosaminoglycan (GAG) production, 2) depletion of bladder sensory nerve neuropeptides, or 3) ischemic degeneration of sensory nerve endings within the bladder wall. Controlled distention of the urinary bladder during cystoscopy has been reported to alleviate clinical signs in some cats with idiopathic FLUTD. However, the efficacy of uro-