Veterinary Medicine - August 2008 - (Page 454)

Demodicosis PEER-REVIEWED TABLE 2 TABLE 3 Recommended Antibiotic Therapy for Staphylococcal Skin Infection in Dogs Name Cephalexin Cefpodoxime Amoxicillin trihydrateclavulanate potassium Clindamycin Enroﬂoxacin* Marboﬂoxacin* Ciproﬂoxacin* Dose 25–30 mg/kg PO b.i.d. 5–10 mg/kg PO once a day 20–25 mg/kg PO b.i.d. 11 mg/kg PO b.i.d. 10–20 mg/kg PO once a day 2.5–5.5 mg/kg PO once a day 10–20 mg/kg PO once or twice a day Reasons for Treatment Failure in Dogs with Demodicosis • Failure to control concurrent bacterial infection • Failure to select an appropriate miticidal drug or failure to administer an appropriate drug at the correct dosage (dose, frequency, duration) • Failure to identify and treat predisposing conditions • Failure to monitor the patient and adjust treatment accordingly • Failure to avoid the use of glucocorticoids or other immunosuppressive agents *We only recommend using these antibiotics if the decision is based on culture and susceptibility testing. Of these three, enro oxacin and marbo oxacin are FDA-approved for use in dogs. frequencies.10,11 Overall, topical amitraz at 0.025% to 0.05% every seven to 14 days is recommended. A suggested protocol for amitraz is listed in Table 4. Pododemodicosis and demodectic otitis can be treated with an extralabel mixture of amitraz and mineral oil (1:9), although this mixture may irritate the otic epithelium in certain individuals.12 Before using an extralabel protocol, it is important to recognize that amitraz is a pesticide registered with the Environmental Protection Agency (EPA). This status makes it a federal violation to use amitraz in a manner contrary to its label. If the label protocol proves to be ineffective, it may be more acceptable to use a macrocyclic lactone instead of extralabel amitraz. Amitraz collars are not recommended for treating demodicosis.10 Amitraz dips are not without risk to dogs and their handlers. Many patients experience mild toxicosis seen as excessive lethargy for one or two days after dipping.8 More overt signs of toxicosis are similar to those seen with the use of alpha2-adrenergic agonists, including sedation, hypothermia, bradycardia, and hyperglycemia. Hyperglycemia is a potential concern in diabetic dogs and clients.13 The use of alpha2-adrenergic antagonists can reverse signs of toxicosis and can be used before dipping in patients with a history of adverse effects.13,14 Atipamezole (50 µg/kg intramuscularly) can reverse the signs of toxicosis within 10 minutes.13 Avoid antidepressants and MAOIs, such as selegiline, in dogs receiving amitraz. Animal handlers administering amitraz should wear protective clothing and apply it in a well-ventilated area. Personnel should be aware of the potential risk for drug interactions. Those with respiratory problems or diabetes should not use amitraz.15 A new spot-on formulation containing meta umizone and amitraz (ProMeris— Fort Dodge Animal Health) is available in the United States to control eas and ticks on dogs. This product was recently evaluated as a topical treatment for generalized demodicosis in a small study involving 16 dogs older than 1 year of age.16 Dogs were divided into two equal groups and treated with the spot-on at the proposed minimum dose rate (20 mg/kg of both meta umizone and amitraz, 0.133 ml/kg) on days 0, 28, and 56 or days 0, 14, 28, 42, 56, and 70. Five sites were scraped for mites throughout the study. Clinical signs improved and mite numbers decreased for both treatment groups. For dogs that received three treatments every 28 days until day 56, 42.9% had negative test results for live mites and eggs. For dogs that received six treatments every 14 days until day 70, 62.5% had negative test results for live mites and eggs. Although the spot-on did improve clinical signs and reduce mite numbers, the study excluded dead mites and mite segments from evaluation. It is also unknown whether dogs cleared of mites relapsed after the study because skin scrapings were not obtained after the treatment was discontinued. The use of a spot-on is an exciting concept, but more critically evaluated trials are needed to substantiate this drug’s ef cacy in the longterm control of generalized demodicosis. It is important to recognize that ProMeris is registered with the EPA. This status makes it a federal violation to use it in a manner inconsistent with its label. Macrocyclic lactones. Macrocyclic lactones include the avermectins (ivermectin and doramectin) and milbemycins (milbemycin oxime and moxidectin). This class of drugs selectively 454 August 2008 VETERINARY MEDICINE

Table of Contents Feed for the Digital Edition of Veterinary Medicine - August 2008

Veterinary Medicine - August 2008 Contents Editors' Note Leading Off ClinQuiz Idea Exchange Practical Matters Diagnosing and Treating Canine Copper-Associated Hepatopathies Canine and Feline Demodicosis CE Form Advertiser Index Product Preview Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.