Permethrin toxicosis in cats

A retrospective analysis of all adverse experience reports received by the Australian Pesticides and Veterinary Medicines Authority's Adverse Experience Reporting Program for veterinary medicines since 1995, showed that permethrin toxicity in cats usually occurred after the owner applied a canine permethrin-containing product, typically a spot-on. Cats are also at risk from grooming or being in direct contact with recently treated dogs. This paper reviews permethrin toxicosis and its treatment in cats, incorporating information from the Australian and selected overseas veterinary pharmacovigilance programs.     

Phase I clinical trial evaluating STI571 in tumor bearing cats

Introduction: STI571 (Gleevec, imatinib mesylate) is a receptor tyrosine kinase inhibitor with selectivity for Bcr‐Abl, platelet‐derived growth factor (PDGF), stem cell factor (SCF), and c‐Kit. Side effects with use in humans include vomiting, diarrhea, nausea, myalgia, edema, and cutaneous reactions. Renal and hepatic toxicity have also been reported. In dogs, there is significant hepatic toxicity at sub‐clinical doses. The purpose of this prospective study was to determine the toxicity level and potential treatment protocol in tumor bearing cats. Methods: A phase I clinical trial was performed in client owned cats using an escalating dose of STI571 in tumor bearing cats. Cats included in the study had a histologic diagnosis of fibrosarcoma or other tumors and were staged with CBC, biochemical profile, thoracic radiographs, and abdominal ultrasound. None of the cats received concurrent chemotherapy, but those previously treated with surgery, radiation therapy, or chemotherapy, were not excluded. The initial starting dose was 5 mg/cat PO SID and was gradually increased to 10 and 20 mg/cat PO SID at a 2–6 week interval depending on laboratory work and disease progression. A repeat physical examination, CBC, and biochemical profile, were performed every 2 weeks for 2 rechecks, then every 4 weeks. Results: Six cats were enrolled in the study. Four cats had oral squamous cell carcinoma, and two cats had cutaneous fibrosarcoma. One cat demonstrated leukocytosis, increased liver enzymes, and signs of acute renal failure two weeks after initiating therapy (5 mg PO SID). No dose escalation was made in this cat. Five cats endured dose escalations of 10 mg PO SID in two cats and 20 mg PO SID in three cats and were treated for 2–4 months. None of these cats experienced any signs of toxicity as measured by CBC and biochemical profile. Conclusions: Only one cat experienced toxicity that may have been associated with low dose administration of STI571. As most cats tolerated the drug without an adverse effect, further evaluation of STI571 in a phase II clinical trial is warranted.     

Tracheal rupture associated with intubation in cats: 20 cases (1996-1998)

OBJECTIVE: To characterize clinical features of tracheal rupture associated with endotracheal intubation in cats and to evaluate the most appropriate treatment for this condition. DESIGN: Retrospective study. ANIMALS: 20 cats with a history of endotracheal intubation that subsequently developed dyspnea or subcutaneous emphysema. PROCEDURE: Medical records of cats with a presumptive diagnosis of tracheal rupture associated with intubation were reviewed. Clinical and clinicopathologic data were retrieved. RESULTS: Cats were evaluated 5 hours to 12 days after a surgical or medical procedure requiring general anesthesia with intubation had been performed. Fourteen (70%) cats were evaluated after dental prophylaxis. All cats radiographed had pneumomediastinum and subcutaneous emphysema. Eighteen of 19 cats were initially treated medically. Duration of medical treatment for cats that did not have surgery ranged from 12 to 72 hours. Cats that had surgery received medical treatment 3 to 24 hours prior to the surgical procedure. Medical treatment alone was administered to 15 cats that had moderate dyspnea, whereas surgical treatment was chosen for 4 cats that had severe dyspnea (open-mouth breathing despite treatment with oxygen) or worsening subcutaneous emphysema. Eighteen cats had improvement of clinical signs, 1 cat died after surgery, and 1 cat died before medical or surgical intervention. CONCLUSIONS AND CLINICAL RELEVANCE: Most cats with tracheal rupture associated with intubation can be treated medically. Cats with worsening clinical signs (severe dyspnea, suspected pneumothorax, or worsening subcutaneous emphysema) should have surgery performed immediately to correct the defect.     

Exogenous Insulin Treatment after Hypofractionated Radiotherapy in Cats with Diabetes Mellitus and Acromegaly

Background: The optimal treatment for feline acromegaly has yet to be established. Surgical and medical therapies are minimally effective although radiotherapy might have greater efficacy. The purpose of this study was to review the response and outcome of cats with acromegaly and insulin-resistant diabetes mellitus (DM) to radiotherapy.
Hypotheses: That radiotherapy improves glycemic control in cats with acromegaly and that improved glycemic control is due to remission of clinical acromegaly; demonstrated by a fall in serum insulin-like growth factor-1 (IGF-1) concentrations.
Animals: Fourteen cats with naturally occurring acromegaly.
Methods: Retrospective case review; records of all cats treated for acromegaly with radiotherapy were reviewed from 1997 to 2008. Cats were selected on the basis of compatible clinical signs, laboratory features, and diagnostic imaging findings. Fourteen cats received radiotherapy, delivered in 10 fractions, 3 times a week to a total dose of 3,700 cGy.
Results: Thirteen of 14 cats had improved diabetic control after radiotherapy. These improvements were sustained for up to 60 months. DM progressed in 2 cats and 1 did not respond. Seven cats responded before the final treatment. Ten cats were euthanized, 1 as a consequence of radiotherapy. In 8 cats in which IGF-1 was measured after treatment, changes in its concentration did not reflect the clinical improvement in glycemic control.
Conclusions and Clinical Importance: Radiotherapy represents an effective treatment for cats with insulin-resistant DM resulting from acromegaly. IGF-1 concentration after treatment does not provide a suitable method by which remission from either acromegaly or insulin-resistant DM may be assessed.     

The inhibitory effect of a combination of imidacloprid and permethrin on blood feeding by mosquitoes in dogs raised under outdoor conditions

Combinations of imidacloprid and permethrin were frequently used to control harmful arthropod of companion animals. The inhibitory effects on blood-feeding activity of mosquitoes in dogs raised under outdoor conditions were evaluated by using combination of 10% (w/v) of imidacloprid and 50% (w/v) of permethrin as spot-on form. Dogs in the treated group received the combination imidacloprid/permethrin spot-on. After treatment, dogs in the control and treated groups were kept separately from the evening (17:00) to the morning of the following day (09:00) in two different kennels installed outdoors to mimic realistic dog-raising conditions. Mosquitoes in the kennels were collected by light traps placed in the kennels and a sweep net to determine evidence of blood feeding, and for species identification. Mosquitoes were collected at Days 5, 3 and 1 before agent treatment, and the Day of treatment, and Days 3, 7, 14, 21, 28, 35 and 42 after treatment. The percentages of blood-fed mosquitoes measured at Days 0, 3, 21, 28 and 42 after treatment were statistically significantly lower (p<0.01) in the treated group than in the control group. The most commonly collected mosquito, Culex tritaeniorhynchus, revealed statistically significant lower percentages (p<0.01) of blood-fed mosquitoes in the treated group than in the control group at the Day of treatment, and Days 3, 7, 21, 28 and 42 after treatment. It appeared that the test agent was effective in inhibiting blood feeding by adult female mosquitoes, and the efficacy lasts for 42 days after treatment under outdoor conditions.     

Evaluation of transdermal application of glipizide in a pluronic lecithin gel to healthy cats

OBJECTIVE: To evaluate plasma glipizide concentration and its relationship to plasma glucose and serum insulin concentrations in healthy cats administered glipizide orally or transdermally. ANIMALS-15 healthy adult laboratory-raised cats. PROCEDURE: Cats were randomly assigned to 2 treatment groups (5 mg of glipizide, PO or transdermally) and a control group. Blood samples were collected 0, 10, 20, 30, 45, 60, 90, and 120 minutes and 4, 6, 10, 14, 18, and 24 hours after administration to determine concentrations of insulin, glucose, and glipizide. RESULTS: Glipizide was detected in all treated cats. Mean +/- SD transdermal absorption was 20 +/- 14% of oral absorption. Mean maximum glipizide concentration was reached 5.0 +/- 3.5 hours after oral and 16.0 +/- 4.5 hours after transdermal administration. Elimination half-life was variable (16.8 +/- 12 hours orally and 15.5 +/- 15.3 hours transdermally). Plasma glucose concentrations decreased in all treated cats, compared with concentrations in control cats. Plasma glucose concentrations were significantly lower 2 to 6 hours after oral administration, compared with after transdermal application; concentrations were similar between treatment groups and significantly lower than for control cats 10 to 24 hours after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Transdermal absorption of glipizide was low and inconsistent, but analysis of our results indicated that it did affect plasma glucose concentrations. Transdermal administration of glipizide is not equivalent to oral administration. Formulation, absorption, and stability studies are required before clinical analysis can be performed. Transdermal administration of glipizide cannot be recommended for clinical use at this time.     

Management of hypertension controls postoperative neurologic disorders after renal transplantation in cats

OBJECTIVES: To determine the prevalence and describe the management of hypertension and central nervous system (CNS) complications after renal transplantation in cats. We also compared the prevalence of CNS complications between cats monitored and treated for postoperative hypertension and a previously described, historical control group of cats not monitored or treated for postoperative hypertension. STUDY DESIGN: Retrospective clinical study. ANIMALS OR SAMPLE POPULATION: A total of 34 client-owned cats that received renal allografts for the treatment of end-stage renal failure. METHODS: Medical records were reviewed. Data obtained included preoperative and postoperative systolic blood pressures, antihypertensive therapy, response to treatment, neurologic signs, and clinical outcome. The results were compared with a historical control group of feline renal allograft recipients that were neither monitored nor treated for postoperative hypertension. RESULTS: Severe postoperative hypertension occurred in 21 of 34 of cats. Hypertension was treated in all 21 cats with subcutaneously administered hydralazine which reduced systolic blood pressure to less than 170 mm Hg in 15 minutes in 20 of 21 cats; hydralazine produced hypotension in one cat and failed to control hypertension in 1 cat. After transplantation, seizures were observed in one cat and other neurologic complications (stupor, ataxia, and central blindness) were observed in three cats. The prevalence of seizures and neurologic complication-related deaths after transplantation was significantly reduced with treatment of postoperative hypertension. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertension is a major contributing factor to postoperative seizure activity after renal transplantation in cats; treatment of hypertension reduces the frequency of neurologic complications.     

Pharmacokinetics and toxicity of zonisamide in cats

With the eventual goal of making zonisamide (ZNS), a relatively new antiepileptic drug, available for the treatment of epilepsy in cats, the pharmacokinetics after a single oral administration at 10mg/kg and the toxicity after 9-week daily administration of 20mg/kg/day of ZNS were studied in healthy cats. Pharmacokinetic parameters obtained with a single administration of ZNS at 10mg/day were as follows: Cmax=13.1microg/ml; Tmax=4.0h; T(1/2)=33.0h; areas under the curves (AUCs)=720.3microg/mlh (values represent the medians). The study with daily administrations revealed that the toxicity of ZNS was comparatively low in cats, suggesting that it may be an available drug for cats. However, half of the cats that were administered 20mg/kg/day daily showed adverse reactions such as anorexia, diarrhoea, vomiting, somnolence and locomotor ataxia.     

Control of urine marking by use of long-term treatment with fluoxetine or clomipramine in cats

OBJECTIVES: To determine whether clomipramine differs from fluoxetine in reducing feline urine marking; whether reduction of marking continues in cats treated >8 weeks; whether recurrence of marking, after abrupt drug withdrawal, is less in cats treated >8 weeks; and whether cats that are successfully treated but resume marking after drug withdrawal can be successfully treated again with the same drug regimen. DESIGN: Positive-controlled, double-masked clinical trial. ANIMALS: 22 neutered cats (2 females, 20 males) > or =1 year old with objectionable urine marking. PROCEDURE: Cats that marked vertically > or =3 times/wk were treated with fluoxetine (1 mg/kg [0.45 mg/lb], q 24 h, PO) or clomipramine (0.5 mg/kg [0.23 mg/lb], q 24 h, PO) for 16 weeks, and efficacy was compared. Recurrence of marking was determined after abrupt withdrawal of fluoxetine at 16 or 32 weeks. Reduction in marking in cats treated with fluoxetine for 8 weeks after returning to marking following drug withdrawal was compared with the initial 8 weeks of successful treatment. RESULTS: Efficacy of fluoxetine and clomipramine was similar. Treatment >8 weeks revealed increasing efficacy in reduction of marking. Return of marking after termination of fluoxetine administration occurred in most cats. Cats successfully treated initially with fluoxetine responded similarly to repeated treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Clomipramine and fluoxetine were equivalent in treating urine marking. Longer treatment increased efficacy. Most cats return to marking after abrupt drug withdrawal. A second course of treatment can be expected to be as effective as the first.     

Efficacy and Dissipation of Permethrin for the Control of the Northern Fowl Mite in Hens

Laying hens were treated with permethrin at the rate of 20 mg per bird to determine efficacy against northern fowl mites Ornithonyssus sylviarum (Canestrini and Fanzago) and the dissipation of residues over a 42-day period. Permethrin provided greater than 99% control of mites for at least 42 days posttreatment as compared to malathion which did not substantially reduce mite infestations. Carbaryl and coumaphos treatment resulted in limited reductions with mite populations recovering by two to three weeks posttreatment.

Maximum residues of permethrin in breast muscle, body fat and the uropidium occurred on day 1 posttreatment and were still present in fatty tissue in detectable quantities on day 42. Residues in egg yolk appeared on day 3 posttreatment and peaked on day 7 with trace quantities still present on day 21. Permethrin was not found in egg white. Low residues were found in the liver and gizzard from day 1 through to day 7.

     

Dose titration of an injectable formulation of lufenuron in cats experimentally infested with fleas

OBJECTIVES: To identify the lowest single dose of lufenuron injected s.c. that results in a 90% disruption of the flea (Ctenocephalides felis) life cycle for 6 months in cats. ANIMALS: 40 domestic shorthair cats (20 males, 20 females) between 5 and 7 months old. PROCEDURE: Cats were randomly assigned to 1 of 5 eight-cat groups and experimentally infested with C. felis on days -8, -7, -6, and -4. On day 0, cats in the 4 treatment groups were treated with an injectable formulation of lufenuron at doses of 2.5, 5, 10, or 20 mg/kg of body weight, respectively. Control cats received the injectable formulation without lufenuron. Experimental infestations were repeated and flea eggs collected at various intervals for 196 days after treatment. Eggs were placed in media and incubated in an insectary for 28 days to determine effects of injectable lufenuron on egg and larval development. Number of adults that emerged from eggs were compared among groups. RESULTS: Lufenuron injected once at a dose of 10 or 20 mg/kg, but not at 2.5 or 5 mg/kg, resulted in a 90% decrease in number of adult fleas emerging from eggs for 196 days after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that control of flea egg and larval development for at least 6 months can be achieved in cats with a single s.c. injection of lufenuron (10 mg/kg). The injectable formulation may provide veterinarians and cat owners an alternative to the tablet formulation of lufenuron.     

Use of a urea breath test to evaluate short-term treatments for cats naturally infected with Helicobacter heilmannii.

OBJECTIVE: To evaluate efficacy of 3 short-term treatments in cats naturally infected with Helicobacter heilmannii. ANIMALS: 29 cats infected with H heilmannii that had positive results for a urea breath test, rapid urease test, and Helicobacter species-specific polymerase chain reaction test. PROCEDURES: Cats anesthetized for routine surgical procedures were randomly allocated to 4 groups: group 1, control cats; group 2, cats treated with azithromycin, tinidazole, ranitidine, and bismuth once daily for 4 days; group 3, cats treated with clarithromycin, metronidazole, ranitidine, and bismuth twice daily for 4 days; and group 4, cats treated with clarithromycin, metronidazole, ranitidine, and bismuth twice daily for 7 days. Efficacy was determined on the basis of results of a urea breath test performed 10 and 42 days after end of treatment. RESULTS: Ten days after treatment, 0 of 4, 4 of 6, 11 of 11, and 8 of 8 cats in groups 1 to 4, respectively, had a negative result for a urea breath test. Forty-two days after treatment, 0 of 4, 3 of 6, 7 of 11, and 4 of 8 cats in groups 1 to 4, respectively, still had a negative result. CONCLUSIONS AND CLINICAL RELEVANCE: Treatments used in this study regularly suppressed breath 13CO2 production. However, although 23 of 25 (92%) cats had negative results for a urea breath test 10 days after treatment, only 14 of 25 (56%) cats still had negative results 42 days after treatment. It is difficult to achieve a definitive long-term cure in cats naturally infected with H heilmannii.     

Photodynamic therapy of feline cutaneous squamous cell carcinoma using a newly developed liposomal photosensitizer: preliminary results concerning drug safety and efficacy

BACKGROUND: Squamous cell carcinomas are common skin tumors in cats. We investigated photodynamic therapy (PDT) using a new liposomal photosensitizer as a minimally invasive, effective treatment that can be easily performed while achieving good cosmetic results. AIM: The goal of this study was to assess and describe possible toxicities using a liposomal formulation of the photosensitizer meta-(Tetrahydroxyphenyl)Chlorin (m-THPC) and investigate if favorable pharmacokinetics translate into favorable tumor response and control. ANIMALS: Eighteen client-owned cats with 20 spontaneous cutaneous squamous cell carcinomas were included in the study. METHODS: PDT was performed using a new, liposomal formulation of the photosensitizer. Toxicity, tumor response, and tumor control were evaluated retrospectively. RESULTS: No general adverse effects were observed in cats treated with the new liposomal formulation. Mild local toxicity such as erythema and edema were seen in 15% of the patients. All cats responded to therapy, with a complete response rate of 100%. The overall 1-year control rate was 75%. The tumor recurrence rate was 20% with a median time to recurrence of 172.25 +/-87.1) days. CONCLUSIONS AND CLINICAL IMPORTANCE: A new liposomal photosensitizer was successfully used for squamous cell carcinoma in cats and was well tolerated. There were no systemic adverse effects observed with the liposomal formulation. The favorable pharmacokinetics of the liposomal drug resulted in a favorable tumor response.     

Evaluation of the safety of fenbendazole in cats

OBJECTIVE: To evaluate the safety of fenbendazole in domestic cats. ANIMALS: 28 six- to seven-month old domestic short-hair cats. PROCEDURE: Cats were randomly assigned to 1 of 3 treatment groups or a control group (n = 7/group). Cats in the treatment groups were given fenbendazole at a dosage of 50, 150, or 250 mg/kg, PO, every 24 hours for 9 days; control cats were given a placebo. A fecal examination, coagulation tests, serum biochemical analyses, CBC, and urinalyses were performed before and 5, 9, and 21 days after initiation of treatment; cats were closely monitored for adverse reactions. After the last dose of fenbendazole was given, 4 control cats and 4 cats given fenbendazole at the highest dosage were euthanatized, and necropsies were performed. RESULTS: None of the cats developed any adverse reactions. For cats in the control and all treated groups, laboratory test results were within reference limits, and there were no significant differences in results of laboratory tests among groups. No gross or histologic lesions were identified in the control or treated cats that were euthanatized. CONCLUSIONS AND CLINICAL RELEVANCE: Fenbendazole administered to healthy cats at a dosage 5 times the dosage and 3 times the duration approved for use in dogs and wild felids did not cause any acute or subacute adverse reactions or pathologic changes. Results suggest that cats may be safely treated with fenbendazole.     

Cisplatin Toxicity in Cats

Cisplatin (cis-diamminedichloroplatinum; Platinol, Bristol, Syracuse, NY) was administered to 11 cats, divided into three groups of experimental and clinical patients. In group 1, cisplatin was administered at a dose of 60 mg/m2 to four cats. In an attempt to avoid renal toxicity, saline diuresis was induced by administering 0.9% saline solution intravenously at a rate of 20 ml/kg/hr for 4 hours before and 2 hours after cisplatin administration. All four cats became dyspneic and died 48-96 hours after cisplatin administration. Postmortem findings included severe hydrothorax, pulmonary edema, and mediastinal edema. In group 2, four experimental cats entered a trial comparing the effects of saline diuresis and cisplatin (60 mg/m2) with the effects of saline diuresis and placebo (0.9% saline solution). The cats in the saline control group remained completely normal, while the cats that received cisplatin developed clinical signs and gross postmortem pulmonary changes identical to those in the first group of cats. Histopathologic examination showed that the alveolar septa were thickened and congested, and contained macrophages, occasional neutrophils, thrombi, and small foci of necrosis and fibrin. Microangiopathic changes were seen in the alveolar capillaries. In the third group, three additional cats were treated with a lower dose of cisplatin. Two cats that received 40 mg/m2 of cisplatin developed pulmonary changes similar to, but less severe than, those seen in the cats that received the higher dose of cisplatin. One cat treated with 20 mg/m2 of cisplatin showed no pulmonary changes ante mortem or post mortem. This series of 11 clinical and experimental cases identifies an apparent species-specific, dose-related, primary pulmonary toxicity of cisplatin in cats.     

Treatment-related toxicities in tumor-bearing cats treated with temozolomide alone or in combination with doxorubicin: a pilot assessment

A retrospective study assessing treatment-related toxicities in tumor-bearing cats treated with temozolomide (TMZ) alone or in combination with doxorubicin was conducted. TMZ was administered orally once a day for 5 days every 3 weeks at a dose of 20 mg/cat. Tumor response was evaluated with standard World Health Organization criteria and toxicity was monitored using veterinary co-operative oncology group-common terminology criteria for adverse events (VCOG--CTCAE) criteria. Ten tumor-bearing cats with various types of malignancies were treated with TMZ-based chemotherapy. Eight cats were evaluable for response. Two cats achieved a complete response, one achieved stable disease and five achieved a partial response. Four grade III and one grade IV hematological toxicities, and one grade IV gastrointestinal toxicity were observed. Four cats were euthanased as a result of apparent toxicity. One cat was euthanased as a result of severe and prolonged myelosuppression with fever. Three were euthanased for grade III pleural and pericardial effusions. Effusion was seen in cats treated with higher cumulative dose of TMZ (P = 0.0046). Planned additional case accrual was discontinued because of unacceptable levels of toxicity despite evidence of efficacy in some of the cats. Additional investigation is needed to elucidate this unexpected apparent cumulative toxicity.     

Is AZT/3TC therapy effective against FIV infection or immunopathogenesis?

In vitro and in vivo prophylactic and therapeutic efficacy of AZT/3TC treatment was evaluated against feline immunodeficiency virus (FIV) infection. In vitro studies utilized FIV-infected peripheral blood mononuclear cells (PBMCs) or FIV-infected T-cell lines treated with AZT (azidothymidine) alone, 3TC alone, or AZT/3TC combination and tested for anti-FIV activity and drug toxicity. AZT/3TC combination had additive to synergistic anti-FIV activities in primary PBMC but not in chronically infected cell lines. In vivo studies consisted of four treatment groups (n=15) of SPF cats receiving AZT/3TC combination (5-75 mg/kg/drug PO BID for 8 or 11 weeks) and one control group (n=9) receiving oral placebo. Group I (n=6, 150 mg/kg/drug/day) was treated starting 3 days pre-FIV inoculation, whereas Group II (n=3, 150 mg/kg/drug/day) and Group III (n=3, 100 mg/kg/drug/day) treatments were simultaneous with FIV inoculation. Group IV treatment (n=3, 100 mg/kg/drug/day) was initiated 2 weeks post-FIV inoculation. All cats were monitored for drug toxicity and FIV infection. Eighty-three percent of cats in Group I and 33% of cats in Groups II and III were completely protected from FIV infection. A significant delay in infection and antibody seroconversion was observed in all unprotected cats from Groups I, II and III. Group IV cats had only a slight delay in FIV antibody seroconversion. Adverse drug reactions (anemia and neutropenia) were observed at high doses (100-150 mg/kg/drug/day) were reversible upon lowering the dose (20 mg/kg/drug/day). In contrast, AZT/3TC treatment had no anti-FIV activity in chronically infected cats. Furthermore, severe clinical symptoms caused by adverse drug reactions were observed in some of these cats. Overall, AZT/3TC treatment is effective for prophylaxis but not for therapeutic use in chronically FIV-infected cats.     

Effects of topical 0.5% tropicamide on intraocular pressure in normal cats

The objective of the study was to determine the effect of topical 0.5% tropicamide on intraocular pressure (IOP) in normotensive feline eyes. IOP was measured bilaterally in 70 clinically healthy cats and gonioscopy (and goniophotography) was performed. Thereafter, 50 cats were treated unilaterally with one drop of 0.5% tropicamide. The contralateral, left eye served as a control. In the placebo group consisting of 20 cats, one drop of physiologic saline solution was administered to the right eye. In all cats, IOP of both eyes was measured 30, 60 and 90 min after topical administration. After unilateral tropicamide application, IOP increased significantly both in the right and in the left eye. Maximum average IOP increase was observed at the control measurement performed 90 min after treatment, with an elevation of 3.8 +/- 4.2 mmHg in the right eye and 3.5 +/- 3.6 mmHg in the left eye. Maximum IOP increase after treatment was 18.0 mmHg in the treated eye and 17.0 mmHg in the left eye. Measurements made at 60 min after treatment revealed a significantly higher increase in IOP in the right eye as compared to the left eye (P60 < 0.05), whereas the differences between right and left eye in IOP increase were not significant at 30 and 90 min after mydriatic application (P30 = 0.123; P90 = 0.305). Although tropicamide-induced mydriasis was observed in the treated eye, the contralateral eye did not show any changes in pupillary function at any time. With increasing age of the cats, IOP increase was found to be more moderate, whereas the gender of the cats did not have any significant influence on IOP changes. In the 20 cats in the placebo group, no significant changes in IOP were observed. We conclude that topical 0.5% tropicamide causes a significant elevation of IOP in the treated and untreated eye in normal cats.     

Permethrin Spot-On Toxicoses in Cats

Spot-on insecticides are becoming a popular type of flea control for pets. Spot-on products available include those containing fipronil, imidicloprid, methoprene, and permethrin. Currently, over 15 brands of permethrin spot-on products are labeled for "use in dogs only." These products contain high concentrations (45–65%) of permethrin insecticide and are becoming a very popular choice for flea and tick control for dogs. Cats are highly sensitive to permethrin and inappropriate or accidental application of these products would be fatal. Though they have a wise margin of safety when used appropriately on dogs, even small amount of permethrin spot-on products can cause severe clinical signs in cats. Indications of this species sensitivity have been documented by the National Animal Poison Control Center (NAPCC). In most cases, the owner applied the concentrated permethrin-containing poduct to cats accidentally or intentionally. In some situations, the exposure seems to have resulted when the product was used on the dog and cats were playing with dog. (ASPCA, NAPCC, Unpublished data, 1995–1997).     

Relative cost-effectiveness of treatment of feedlot calves with ivermectin versus treatment with a combination of fenbendazole, permethrin, and fenthion

OBJECTIVE: To compare growth performance, animal health characteristics, and carcass characteristics of feedlot calves treated with ivermectin topically with that of feedlot calves treated with a combination of fenbendazole orally and permethrin and fenthion topically. DESIGN: Clinical trial. ANIMALS: 14,184 British crossbred steer calves (mean weight, 286 kg [630 lb]) in 30 pens at a commercial feedlot in Nebraska. PROCEDURE: On arrival at the feedlot, calves were randomly assigned to be treated with ivermectin topically or with a combination of fenbendazole orally and permethrin and fenthion topically (control). At the time of assignment to treatment groups, fecal samples were collected from 5% of the calves. Growth performance, carcass characteristics, and health information were recorded. RESULTS: Geometric mean fecal egg counts at the time of arrival at the feedlot were not significantly different between groups. Final weight, weight gain, average daily gain, and the dry matter intake-to-gain ratio were significantly improved for calves in the ivermectin group. The percentage of carcasses classified as quality grade choice was higher for the ivermectin group than the control group; however, the percentage of carcasses classified as yield grade 1 and the dressing percentage were higher for the control group than for the ivermectin group. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical administration of ivermectin to feedlot calves is relatively more cost-effective than administration of a combination of fenbendazole orally and permethrin and fenthion topically.