Veterinary Medicine - September 2007 - (Page 580)

Practical Matters clinical advice and reminders from your colleagues O PEER-REVIEWED Use caution when prescribing transdermal medications for feline behavior problems M edicating a headstrong cat can be a challenge. However, compounding pharmacies have made the task easier by preparing many medications as flavored liquids, chewable treats, or transdermal gels. When prescribing transdermal medications, only consider drugs that are proven effective when used transdermally or that have an objective, measurable response to treatment. For example, the efficacy of transdermal methimazole for treating hyperthyroidism can be confirmed through the resolution of clinical signs and by measuring serum thyroxine concentrations. Evaluating the analgesic effects of a transdermal medication involves subjective observation. However, studies on fentanyl in dogs and cats, for example, clearly demonstrate that therapeutic blood concentrations are achieved when fentanyl is administered through a transdermal patch.1,2 Evaluating a drug’s efficacy for treating behavioral disorders is even more subjective. When using a transdermal behavioral drug, it is difficult to assess whether failure to achieve the desired behavioral response (e.g. cessation of urine spraying) is due to inadequate blood concentrations or to a cat that is simply a nonresponder to that medication. In addition, studies of amitriptyline, buspirone, and fluoxetine have shown that transdermal administration achieves only a fraction of the concentration achieved when these drugs are given orally in single dosing trials.3,4 Thus, when prescribing medications for fussy cats, work with your compounding pharmacy to see what formulations are available. But save the transdermal behavioral drugs as a last resort for cats that will not tolerate oral medication. REFERENCES Arnold Plotnick, MS, DVM, DACVIM, DABVP 1. Kyles AE, Papich M, Hardie EM. Disposition of transdermally administered fentanyl in dogs. Am J Vet Res 1996;57:715-719. 2. Scherk-Nixon M. A study of the use of a transdermal fentanyl patch in cats. J Am Anim Hosp Assoc 1996;32:19-24. 3. Mealey KL, Peck KE, Bennett BS, et al. Systemic absorption of amitriptyline and buspirone after oral and transdermal administration to healthy cats. J Vet Intern Med 2004;18:43-46. 4. Ciribassi J, Luescher A, Pasloske KS, et al. Comparative bioavailability of fluoxetine after transdermal and oral administration to healthy cats. Am J Vet Res 2003;64:994-998. Radiography helps confirm complete radiopaque calculi removal O PEER-REVIEWED C Manhattan Cat Specialists 230 West 76th St. New York, NY 10023 ystotomy is commonly performed in small-animal practice to remove cystic calculi that cannot be treated medically or with other nonsurgical extraction techniques (urohydropropulsion, catheter or basket removal). Unfortunately, if numerous smaller calculi are present in the bladder and urethra, particularly in male dogs, the risk of leaving calculi after cystotomy can be as high as 15% to 20%.1 Residual calculi may be responsible for acute urethral obstruction and can cause a poor response to antibiotic therapy for bladder infections after surgery. In addition, incomplete calculi evacuation may be misinterpreted as a failure of the medical therapy to prevent stone recurrence after surgery and may unnecessarily alter future diagnostic test and treatment plans. When calculi have been removed completely yet the condition recurs early after surgery, owners may blame the surgeon for incomplete removal. Thus, to verify complete calculi removal and reduce these concerns, take orthogonal radiographs after cystotomy. REFERENCE Daniel D. Smeak, Save the transdermal behavioral drugs as a last resort for cats that will not tolerate oral medication. 580 September 2007 VETERINARY MEDICINE DVM, DACVS James L. Voss Veterinary Teaching Hospital College of Veterinary Medicine and Biomedical Sciences Colorado State University Fort Collins, CO 80523 1. Lulich JP, Osborne CA, Felice LD, et al. Managing calcium oxalate urolithiasis, in Proceedings. 11th Annu Meet Am Coll Vet Intern Med 1993;374-377. ©iStockphoto.com/Luis Sierra, Erik Reis

Table of Contents Feed for the Digital Edition of Veterinary Medicine - September 2007

Contents Letters Leading Off The Veterinary Medicine Interview: Dr. William J. Kay Idea Exchange Practical Matters Salivary Mucoceles in Cates: A Retropspective Study of Seven Cases Hyperlipidemia in Dogs and Cats Purina Insert The Latest Management Recommendations for Cats and Dogs with Nonketotic Diabetes Mellitus CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - September 2007

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