Treatment of feline giardiasis with metronidazole

Seven cats from a single household with 17 cats were shedding cysts of Giardia species as detected by a modified zinc sulfate concentration technique. All the cats were housed individually in Horsfal isolation units for the duration of the evaluation, treatment, and follow-up monitoring. Each of the infected cats was treated with metronidazole at a dose of 22 mg per kg of body weight, twice a day, for 5 days. Post-treatment examination of four or five stool samples from each cat during the following 17 days did not reveal the presence of any giardial cysts in the treated cats. After treatment, the diarrhea either ceased or was markedly diminished. Therefore, metronidazole appears to be an effective form of therapy for feline giardiasis.     

Aelurostrongylus abstrusus (cat lungworm) infection in five cats from Italy

Infection by the cat lungworm Aelurostrongylus abstrusus is considered uncommon. Here, the authors report the clinical, diagnostic and therapeutic features of five infections recently observed in Italy. All cats were under 12 months of age. All except one cat had symptomatic infections, with cough, dyspnea, and weight loss with radiographic signs of broncopneumonia. All cats were eosinophilic. Larvae were present in fresh fecal smears and on flotation exam in all cats. Baermann larval recovery permitted definitive identification and, in one case, larvae per gram of feces (lpg) counts. One dose of ivermectin (400 microg/kg) was not effective in one cat, while one dose of selamectin (6 mg/kg) was effective in one of three cases and fenbendazole at 50 mg/kg given daily for 15 days was effective in four of four cases.     

The safety of high‐dose buprenorphine administered subcutaneously in cats

The safety of a proprietary formulation of buprenorphine hydrochloride administered subcutaneously (SC) to young cats was investigated in a blinded, randomized study. Four cohorts of eight cats aged approximately 4 months were administered saline, 0.24, 0.72 or 1.20 mg/kg/day buprenorphine SC for nine consecutive days, representing 0×, 1×, 3× and 5× of the intended dose. Cats were monitored daily for evidence of clinical reactions, food and water intake and adverse events (AEs). Physical examinations, clinical pathology, vital signs and electrocardiograms (ECGs) were evaluated at protocol‐specified time points. Complete necropsy and histopathologic examinations were performed following humane euthanasia. Four buprenorphine‐treated cats experienced AEs during the study, two unrelated and two related to study drug administration. The two cats with AEs considered related to drug administration had clinical signs of hyperactivity, difficulty in handling, disorientation, agitation and dilated pupils in one 0.24 mg/kg/day cat and one 0.72 mg/kg/day cat. All of these clinical signs were observed simultaneously. There were no drug‐related effects on survival, injection response, injection site inspections, body weight, food or water consumption, bleeding time, urinalysis, respiration rate, heart rate, ECGs, blood pressures, body temperatures, macroscopic examinations or organ weights. Once daily buprenorphine s.c. injections at doses of 0.24, 0.72 and 1.20 mg/kg/day for 9 consecutive days were well tolerated in young domestic cats.     

Metronidazole for the treatment of feline giardiasis

There are several drugs available for the treatment of giardiasis in cats, including metronidazole. The purpose of this study was to determine whether metronidazole benzoate administered at a dose of 25 mg/kg, orally, twice a day for 7 days lessens or eliminates Giardia cyst shedding in cats with chronic infection. Twenty-six, adult, laboratory-reared cats were used in this study. Sixteen cats had been inoculated orally with cysts of a human Giardia sp. isolate and had completed a Giardia vaccine study in one animal holding room. The other ten cats were infected with the same Giardia sp. presumably by contamination from the adjacent room where the Giardia vaccine study cats were located. From each cat, a fecal sample was collected within 1 week of the start of treatment and then every 2 to 4 days for 15 days after treatment was completed. Fecal samples were analyzed for the presence of Giardia cysts using a commercially available direct immunofluorescence test (IFA). Clinical signs of drug toxicity were not detected during the study.     

Ketoconazole in the treatment of dermatomycosis in cats and dogs

Ketoconazole (Nizoral^®, Janssen Pharmaceutica) a new systemic antimycotic was tested in dermatomycosis in cats and dogs. The daily dose (10 mg/kg body weight) was administered for 10 or 20 days without any other measures being taken. After the 20‐day treatments new hair growth was observed in 96.7 per cent of the cats and 89.9 percent of the dogs. Clinical cure was complete in 96.8 per cent of the cats and 90.5 per cent of the dogs.

Particularly the good tolerance in the cat was appreciated. There were practically no side‐effects in dogs (except vomiting in two pups) or in cats.     

Toxicologic evaluation of chlorpyrifos in cats

Twenty-four male domestic shorthair cats were used to evaluate the acute and chronic effects of a single, toxic but sublethal, orally administered dose of chlorpyrifos. A dosage of 10 mg/kg of body weight did not induce clinical signs of toxicosis, but a dosage of 40 mg/kg induced clinical signs of toxicosis, and 1 of 12 cats died. Chlorpyrifos given at a dosage of 0.1 mg/kg to 2 cats reduced whole blood and plasma cholinesterase (Che) activities to values obtained after cats were given doses that induced clinical signs of toxicosis. Regeneration time for whole blood and plasma Che activities ranged from 7 to 28 days. Brain Che activity was considerably decreased in 1 cat that died 4.5 hours after dosing, but was normal in all others at 28 days after dosing. Other than decreased Che activity, significant changes were not seen in hematologic or serum biochemical values. Toxin-related lesions were not seen during macroscopic or microscopic examination.     

Suppression of cortisol responses to exogenous adrenocorticotrophic hormone, and the occurrence of side effects attributable to glucocorticoid excess, in cats during therapy with megestrol acetate and prednisolone.

The major purpose of this investigation was to determine the effect of prednisolone and megestrol acetate in cats on the adrenal cortisol response to exogenous adrenocorticotrophic hormone during drug administration at dose rates employed for management of some inflammatory feline dermatoses. Prednisolone (at least 2 mg/kg/day) and megestrol acetate (5 mg/cat/day) were each administered orally to seven cats from days 1 to 16. Three additional cats received no therapy. Basal and stimulated cortisol concentrations, food and water intake, hematology, blood biochemistry, urinalyses, and hepatic and cutaneous histology were studied in all cats before, during, and two weeks following the end of treatment. Cats given prednisolone or megestrol acetate had significant suppression of stimulated cortisol levels on day 8. This change was more marked on day 15, when the suppression in cats given megestrol acetate was also significantly more severe than in those receiving prednisolone. Recovery of adrenal reserve was considered present on day 30 in six of seven cats given prednisolone, but in only three of seven receiving megestrol acetate. Eosinopenia, glycosuria and hepatocyte swelling from glycogen deposition were occasionally recorded in treated cats of both groups, providing additional circumstantial evidence for glucocorticoid activity of megestrol acetate in cats. It is advised that abrupt withdrawal of prednisolone or megestrol acetate therapy be avoided in this species to reduce the chance of precipitating clinical signs of hypoadrenocorticism, even after treatment for as little as one week.     

Chloramphenicol toxicosis in cats

Six cats were given chloramphenicol orally at the dose level of 120/mg/kg/day in 3 divided doses for 14 days and were then observed for another 3 weeks after treatment. Five other cats were used as untreated controls for the first 14 days and subsequently were given 60 mg of chloramphenicol/kg/day for 21 days. Clinical signs of toxicosis, which were more severe in cats given the higher dose level, included central nervous system depression, dehydration, reduced food intake, body weight loss, sporadic diarrhea, and vomiting. In cats given the higher dose level, chloramphenicol caused reversible marrow suppression, with marrow hypoplasia, maturation arrest of erythroid cells, and inhibition of mitotic activity, and caused vacuolation of lymphocytes and of early myeloid and erythroid cells. Significant changes were evident in bone marrow after treatment for 1 week and in peripheral blood at the end of the 2nd week. Hematologic changes included decreased numbers of neutrophils, lymphocytes, reticulocytes, and platelets. In cats given the lower dose level, changes in blood and bone marrow were similar but less severe.     

Ketoconazole in the treatment of dermatomycosis in cats and dogs

Ketoconazole (Nizoral, Janssen Pharmaceutica) a new systemic antimycotic was tested in dermatomycosis in cats and dogs. The daily dose (10 mg/kg body weight) was administered for 10 or 20 days without any other measures being taken. After the 20-day treatments new hair growth was observed in 96.7 per cent of the cats and 89.9 per cent of the dogs. Clinical cure was complete in 96.8 per cent of the cats and 90.5 per cent of the dogs. Particularly the good tolerance in the cat was appreciated. There were practically no side-effects in dogs (except vomiting in two pups) or in cats.     

Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection

OBJECTIVES: To determine the efficacy of ronidazole (RDZ), tinidazole (TDZ), and metronidazole (MDZ) against Tritrichomonas foetus in vitro and of RDZ for treatment of feline naturally occurring or experimentally induced T. foetus infection. ANIMALS: A cat naturally infected with T. foetus infection and diarrhea. Ten specific-pathogen-free (SPF) kittens. PROCEDURE: RDZ, TDZ, and MDZ were tested for activity against 3 different feline isolates of T. foetus in vitro. RDZ then was administered to a naturally infected cat at 10 mg/kg PO q24h for 10 days. SPF kittens were infected orogastrically with feline T. foetus and treated with either placebo or RDZ (10 mg/kg PO q12h for 14 days). Cats with relapsing infection or those receiving placebo were treated subsequently with RDZ (either 30 or 50 mg/kg PO q12h for 14 days). Feces were examined for T. foetus by direct microscopy, culture, and polymerase chain reaction (PCR) testing weekly. RESULTS: Both RDZ and TDZ killed T. foetus at concentrations >0.1 microg/mL in vitro. In the naturally infected cat, RDZ abolished diarrhea and T. foetus infection for 85 days after treatment, at which time infection and diarrhea relapsed. Retreatment with RDZ eradicated diarrhea and T. foetus infection for over 407 days. In experimentally induced infection, RDZ at 10 mg/kg caused initial improvement, but infection relapsed in all 5 cats 2 to 20 weeks after treatment. At 30 or 50 mg/kg, 10/10 cats were negative for T. foetus infection for follow-up durations of 21 to 30 weeks after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of RDZ at 30 to 50 mg/kg q12h for 14 days resolved diarrhea and eradicated infection (on the basis of polymerase chain reaction [PCR] testing) in 1 naturally infected cat and 10 experimentally inoculated cats receiving a different isolate of T. foetus.     

Pharmacokinetics of phenobarbital in the cat following multiple oral administration.

Phenobarbital was administered orally to seven healthy cats at a dose of 5 mg/kg once a day for 21 days. Serum phenobarbital concentrations were determined using a commercial immunoassay technique. A one-compartment model was used to describe the final elimination curve. The elimination half-life (t1/2 b) after the final day of treatment was 43.3 +/- 2.92 h. The large apparent volume of distribution of 695.0 +/- 43.9 mL/kg suggests that the drug was widely distributed within the body. The t1/2 b following multiple oral administration was significantly shorter than previously reported for a single oral dose of phenobarbital in the cat. Analysis of pharmacokinetic results after days 1 and 21 of treatment suggested that the elimination kinetics of phenobarbital did not change significantly with multiple oral administration. It appears that differences in elimination kinetics can exist between populations of cats. These differences emphasize the need for individual monitoring of cats receiving phenobarbital.     

Diagnosis and treatment of pyogranulomatous panniculitis due to Mycobacterium smegmatis in cats

Four cats with extensive pyogranulomatous panniculitis and dermatitis due to Mycobacterium smegmatis were evaluated over an eight-month period. All were treated initially with doxycycline (50 mg per cat every eight to 12 hours) for several weeks, then subjected to radical surgical excision of infected tissues. Reconstructive surgery utilising advancement flaps was required to close wounds without undue tension. Postoperatively, the cats received parenteral gentamicin (2 mg/kg every eight hours) for three to five days, followed by orally administered ciprofloxacin (62.5 mg per cat every eight hours or 125 mg per cat every 12 hours) for three to six months. Infection was eradicated in all the cats, with no signs of recurrence 15 to 23 months after surgery.     

The Effects of Consecutive Day Propofol Anesthesia on Feline Red Blood Cells

This study investigated the potential for multiple exposures of propofol to induce oxidative injury, in the form of Heinz body production, to feline red blood cells. Anesthesia was induced in six healthy cats with propofol (6 mg/kg, intravenous [IV]) and maintained for 30 minutes with a propofol infusion (0.20 to 0.30 mg/kg/min, IV). The initial protocol was designed for each cat to receive 10 consecutive days of propofol anesthesia. All cats spontaneously breathed room air. Heart rate, respiratory rate, and indirect blood pressure were measured and recorded before and during anesthesia. Time to complete recovery after each infusion was measured and recorded. Heinz body analysis was performed before and after each day of propofol anesthesia. Based on predetermined criteria for discontinuing daily infusions, the mean number of consecutive days of propofol anesthesia was six and propofol administration did not continue beyond 7 days in any cat. Heart rate, respiratory rate, and indirect blood pressure did not change significantly during propofol anesthesia compared with awake values. Following the third consecutive day of propofol anesthesia, there was a significant increase from baseline in the mean percentage of Heinz bodies. Hemolysis was not detected in any cat. Recovery time significantly increased after the second consecutive day of propofol anesthesia compared with the first day. Five of six cats developed generalized malaise, anorexia, and diarrhea on day 5, 6, or 7, and two cats developed facial edema. All clinical signs resolved without treatment 24 to 48 hours after discontinuing propofol anesthesia. This study suggests that consecutive day propofol anesthesia in normal cats can induce oxidative injury to feline red blood cells in the form of excessive Heinz body formation, result in increased recovery times, and result in clinical signs of illness.     

Treatment of 46 cats with porcine lente insulin--a prospective, multicentre study

This prospective, multicentre, non-blinded, open study followed 46 cats with diabetes mellitus during treatment with porcine lente insulin (also known as porcine insulin zinc suspension, Caninsulin, Intervet) for 16+/-1 weeks (stabilization phase), with additional monitoring of some cats (n=23) for a variable period. At least three of the following were present at initial presentation: appropriate history of clinical signs consistent with diabetes mellitus, glucosuria, blood glucose greater than 15 mmol/l and fructosamine greater than 380 micromol/l. Insulin treatment was started at a dose rate of 0.25-0.5 IU/kg body weight twice daily, with a maximum starting dose of 2 IU/injection. Twenty-eight of the cats were classed as reaching clinical stability during the study, in 23 of these cats this was during the stabilization phase. Seven cats went into remission during the stabilization phase and one of the cats in week 56. Clinical signs of hypoglycaemia, significantly associated with a dose of 3 units or 0.5 IU/kg or more per cat (twice daily), were observed in nine of the 46 cats during the stabilization phase and concomitant biochemical hypoglycaemia was recorded in most cases. Biochemical hypoglycaemia, recorded in 6% of the blood glucose curves performed during the stabilization phase, was significantly associated with a dose rate of 0.75 IU/kg or more twice daily. This further highlights the need for cautious stepwise changes in insulin dose. The protocol used in the present study is suitable for and easy to use in practice. This study confirmed the efficacy and safety of porcine lente insulin (Caninsulin) in diabetic cats under field conditions.     

The effect of opioid and acepromazine premedication on the anesthetic induction dose of propofol in cats

The median effective dosage (ED50) for induction of anesthesia with propofol was determined by using the up-and-down method in 31 unpremedicated cats, in 30 cats premedicated with butorphanol, 0.4 mg/kg body weight (BW), and acepromazine, 0.1 mg/kg BW, intramuscularly, and in 30 cats premedicated with morphine, 0.2 mg/kg BW, and acepromazine, 0.1 mg/kg BW, intramuscularly. The dose required for a satisfactory anesthetic induction in 50% of unpremedicated cats (ED50) was 7.22 mg/kg BW and of premedicated cats was 5.00 mg/kg BW. The reduction in dose was statistically significant in both premedicated groups compared with no premedication. There was no significant difference in ED50 between premedication regimes. Cyanosis was the most common adverse effect observed in all groups following anesthetic induction with propofol.     

Amlodipine: A Randomized, Blinded Clinical Trial in 9 Cats with Systemic Hypertension

The efficacy of amlodipine (AML) was tested in hypertensive cats in a placebo-controlled, randomized, blinded clinical trial. Five cats were randomized to receive 0.625 mg AML once daily and 4 cats to receive placebo (PLA) once daily. The average systolic blood pressure (SBP) recorded by the Doppler method on day 0 was 212 ± 21 mm Hg in the AML group and 216 ± 32 mm Hg in the PLA group. On day 7, the cats receiving AML had a significantly lower average daily SBP (160 ± 30 mm Hg) but SBP in the PLA group was unchanged (207 ± 31 mm Hg). On day 7, all cats receiving PLA and one cat receiving AML were crossed over to the other group because of inadequate response. Blood pressure did not decrease adequately in 3 cats by day 14 (7 days of PLA and 7 days AML) and the treatment code was broken. Each of these cats was subsequently administered 1.25 mg AML daily. Cats requiring 1.25 mg AML once daily (6.1 kg ± 0.7 kg) weighed significantly more than cats that responded to 0.625 mg AML once daily (4.1 ± 0.7 kg). The average daily SBP recorded in the 6 cats that completed the study was significantly lower after 16 weeks of treatment (152 ± 14 mm Hg) compared to day 0 (221 ± 24 mm Hg). Three cats were euthanized before completion of the study. All 3 cats were responders to AML on day 7. SBPs measured 24 hours after AML administration were similar to the average daily SBP, suggesting that AML effectively controlled SBP for a 24-hour period. AML was shown to be an effective once-daily antihypertensive agent when administered to cats at a dosage of 0.18 ± 0.03 mg/kg sid.     

Systemic toxicosis associated with azathioprine administration in domestic cats.

Five cats were treated with an azathioprine suspension (2.2 mg/kg of body weight on alternate days) and 2 cats were given vehicle (controls) for 9 weeks. Complete blood and platelet counts and serum biochemistry variables were monitored weekly. Bone marrow aspirates were evaluated every 3 weeks, and core bone marrow biopsy was performed at the end of the study. Profound neutropenia (less than 600 cells/microliters) was observed in all treated cats, and 1 cat developed pancytopenia. Treatment was discontinued if the WBC count was less than 3,000 cells/microliters. Four weeks after discontinuation of azathioprine, 1 treated cat again was given azathioprine at a lower dosage (1.1 mg of azathioprine/kg on alternate days) and neutropenia recurred within 2 weeks. During treatment, 3 cats developed thrombocytosis, and 2 developed thrombocytopenia. In 4 of 5 cats, neutropenia and thrombocytopenia resolved when azathioprine was discontinued. Bone marrow cytologic examination during treatment revealed reduction of the neutrophil line, with relative increase in monocytes. Core bone marrow biopsy at the completion of the study revealed hypocellular marrow with marked decrease in the myeloid series in cats given azathioprine. One of the cats that was treated with azathioprine had a hypercellular marrow with increased numbers of mature granulocytes and precursors; however, azathioprine had been discontinued 3 weeks prior to biopsy. Alterations in serum biochemical variables were not associated with azathioprine. Two cats that were treated with azathioprine developed respiratory tract infections, and 1 of them was euthanatized during the study.     

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.     

Giardiasis in a horse

Giardia infection was believed responsible for chronic diarrhea, weight loss, lethargy, inappetence, and dermatitis in a 4-year-old Thoroughbred horse. Fecal cysts were detected by the zinc sulfate centrifugal flotation method. All clinical signs resolved upon treatment with metronidazole suspension (5 mg/kg body weight per os, TID for 10 days).     

Itraconazole for the Treatment of Cryptococcosis in Cats

Itraconazole was used in 35 cats with cryptococcosis. Treatment response was determined by comparing clinical signs before, during, and after treatment. It could not be evaluated in 7 cats because they died during treatment from causes unrelated to cryptococcosis. Of the remaining 28 cats, treatment response was classified as success in 16 cats (57%), as improvement in 8 cats (29%), and as a failure in 4 (14%). The failures were due to death or euthanasia from drug toxicity (1 cat), progressive fungal disease (2 cats), and relapse 1 year after treatment (1 cat). The cats that improved did not undergo a 1 -year posttreatment evaluation because they were lost to follow-up (3 cats), died or were euthanatized for other reasons (4 cats), or had a noncompliant owner (1 cat). For the 16 cats in which treatment was successful, the median itraconazole dose was 13.8 mg/kg body weight daily (range, 10.9 to 26.7 mg/kg/d), and the median duration of treatment was 8.5 months (range, 4 to 16 months). Five of these cats had previously been treated unsuccessfully with ketoconazole.