Systemic absorption and adverse ocular and systemic effects after topical ophthalmic administration of 0.1% diclofenac to healthy cats.

OBJECTIVE: To quantify plasma concentrations and determine adverse ocular, renal, or hepatic effects associated with repeated topical ophthalmic application of 0.1% diclofenac to healthy cats. ANIMALS: 8 healthy sexually intact male cats. PROCEDURES: A randomized, placebo-controlled crossover study was conducted. A topical formulation of 0.1% diclofenac was administered 4 times/d for 7 days to 4 cats, and artificial tear (control) solution was administered to the other 4 cats. After a 12-day washout period, cats received the other treatment. Ophthalmic examinations were performed daily. Plasma samples were obtained on days 1 and 7 for pharmacokinetic analysis. A CBC, serum biochemical analysis, urinalysis, determination of urine protein-to-creatinine ratio, and determination of glomerular filtration rate were performed before the start of the study and after each 7-day treatment period. RESULTS: Mild conjunctival hyperemia was the only adverse ocular effect detected. Maximal drug concentration and area under the curve were significantly higher on day 7 than on day 1. Diclofenac-treated cats had a significantly lower glomerular filtration rate than did control-treated cats after the second but not after the first treatment period, presumably associated with iatrogenic hypovolemia. CONCLUSIONS AND CLINICAL RELEVANCE: Topical ophthalmic administration of 0.1% diclofenac was well tolerated in healthy cats, with only mild signs of ocular irritation. Detectable systemic concentrations of diclofenac were achieved with accumulation over 7 days. Systemic absorption of diclofenac may be associated with reduced glomerular filtration rate, particularly in volume-contracted animals. Topical ophthalmic 0.1% diclofenac should be used with caution in volume-contracted or systemically ill cats.

Multiple endocrine diseases in dogs: 35 cases (1996-2009).

OBJECTIVE: To characterize a population of dogs from a tertiary care center with 2 or more endocrine disorders, including the specific disorders and time intervals between diagnosis of each disorder. DESIGN: Retrospective case series. ANIMALS: 35 dogs with 2 or more endocrine disorders. PROCEDURES: Medical records were reviewed, and the following was recorded: clinical signs, physical examination findings, and the results of CBC, serum biochemical analysis, urinalysis, aerobic bacterial culture of urine samples, endocrine testing, diagnostic imaging, and necropsy. RESULTS: 35 dogs with more than 1 endocrine disorder were identified. Seventy-seven percent (27/35) of the dogs were male, and the mean age at the time of diagnosis of the first endocrinopathy was 7.9 years. Miniature Schnauzer was the most common breed. Twenty-eight of 35 (80%) dogs had 2 disorders; 7 (20%) had 3 disorders. The most common combinations of disorders included diabetes mellitus and hyperadrenocorticism in 57.1 % (20/35) of dogs; hypoadrenocorticism and hypothyroidism in 22.9% (8/35) of dogs; and diabetes mellitus and hypothyroidism in 28.6% (10/35) of dogs. A mean of 14.5 months elapsed between diagnosis of the first and second endocrine disorders, whereas there was a mean of 31.1 months between diagnosis of the first and third endocrine disorders. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the occurrence of multiple endocrine disorders was uncommon in dogs. The most common combinations of endocrine disorders in this population of dogs were diabetes mellitus and hyperadrenocorticism, followed by hypoadrenocorticism and hypothyroidism.

The use of vascular access ports for blood collection in feline blood donors.

We investigated vascular access ports for feline blood donation. Eight cats were anesthetized for conventional blood collection by jugular venipuncture at the beginning and end of the study. In-between conventional collections, vascular access ports were used for collection with or without sedation every 6 to 8 wk for 6 mo. Ports remained functional except for one catheter breakage, but intermittent occlusions occurred. Systolic blood pressure was lower during conventional collection. Behavioral abnormalities occurred during 3 port collections. Packed red cells prepared from collected blood were stored at 4°C for 25 d and assessed for quality pre- and post-storage. With both collection methods, pH and glucose level declined, and potassium level, lactate dehydrogenase activity and osmotic fragility increased. There were no differences between methods in pre-storage albumin and HCO(3)(-) levels, and pre and post-storage hematocrit, lactate dehydrogenase activity, and glucose and potassium levels. Pre-storage pH and pCO(2) were higher with conventional collection, and pre- and post-storage osmotic fragility were greater with port collection. One port became infected, but all cultures of packed red cells were negative. Tissue inflammation was evident at port removal. In a second study of conventional collection in 6 cats, use of acepromazine in premedication did not exacerbate hypotension. The use of vascular access ports for feline blood donation is feasible, is associated with less hypotension, and may simplify donation, but red cell quality may decrease, and effects on donors must be considered.

Investigation of the use of three electroencephalographic electrodes for long-term electroencephalographic recording in awake and sedated dogs.

OBJECTIVE: To compare electroencephalography (EEG) artifact associated with use of the subdermal wire electrode (SWE), gold cup electrode (GCE), and subdermal needle electrode (SNE) over an 8-hour period in sedated and awake dogs. ANIMALS: 6 healthy dogs. PROCEDURES: 8 EEG channels were recorded during 20-minute video-EEG recording sessions (intermittently at 0.5, 2, 4, 6, and 8 hours) with and without chlorpromazine sedation. Nonphysiologic artifacts were identified. Duration of artifact was summed for each channel. Number of unaffected channels (NUC) was determined. RESULTS: NUC was significantly affected by electrode type and sedation over time; median for SWE (2.80 channels; 95% confidence interval [CI], 0.84 to 5.70 channels) was significantly different from medians for GCE (7.87 channels; 95% CI, 7.44 to 7.94 channels) and SNE (7.60 channels; 95% CI, 6.61 to 7.89 channels). After 4 hours, NUC decreased in awake dogs, regardless of electrode type. In awake dogs, duration of artifact differed significantly between SWE and GCE or SNE; medians at 8 hours were 61.55 seconds (95% CI, 21.81 to 173.65 seconds), 1.33 seconds (95% CI, 0.47 to 3.75 seconds), and 21.01 seconds (95% CI, 6.85 to 64.42 seconds), respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The SWE had a significant duration of artifact during recording periods > 2 hours, compared with results for the GCE and SNE, in awake dogs. The GCE, SNE, and sedation resulted in significantly more channels unaffected by artifact. For longer recordings, caution should be exercised in selecting EEG electrodes and sedation state, although differences among electrodes may not be clinically relevant.

Multiple endocrine diseases in cats: 15 cases (1997-2008).

The objective of this retrospective study was to characterize a population of cats from a tertiary care center diagnosed with multiple endocrine disorders, including the specific disorders and time intervals between diagnosis of each disorder. Medical records of 15 cats diagnosed with more than one endocrine disorder were reviewed. The majority of cats were domestic shorthairs, and the mean age at the time of diagnosis of the first disorder was 10.3 years. The most common combination of disorders was diabetes mellitus and hyperthyroidism. Two cats had concurrent diabetes mellitus and hyperadrenocorticism, one cat had concurrent central diabetes insipidus and diabetes mellitus. A mean of 25.7 months elapsed between diagnoses of the first and second endocrine disorder, but this was variable. This study suggests the occurrence of multiple endocrine disorders is uncommon in cats.

Effects of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs.

OBJECTIVE: To determine effects of therapeutic dosages of aspirin, carprofen, deracoxib, and meloxicam on platelet function and systemic prostaglandin concentrations in healthy dogs. ANIMALS: 10 hound-crossbred dogs. PROCEDURES: Aspirin (10 mg/kg, PO, q 12 h), carprofen (4.4 mg/kg, PO, q 24 h), deracoxib (2 mg/kg, PO, q 24 h), meloxicam (0.1 mg/kg, PO, q 24 h), and a placebo were administered for 7 days in a random order to each of 10 healthy dogs; there was a 21-day washout period between subsequent treatments. One-stage prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, and plasma concentrations of thromboxane (TX)B(2) and 6-keto prostaglandin (PG)F(1alpha) were measured before and after treatment administration. Platelet function was assessed by use of a platelet-function analyzer and aggregation. RESULTS: Aspirin, carprofen, and meloxicam did not significantly affect platelet function. Deracoxib caused a mild decrease in platelet aggregation induced by 50microM ADP. Platelet number, Hct, PT, aPTT, and plasma TXB(2) and 6-keto PGF(1alpha) concentrations were unchanged after NSAID administration. Meloxicam administration resulted in a significant decrease in fibrinogen concentration, but results remained within the laboratory reference interval. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of commonly used NSAIDs at therapeutic dosages in healthy dogs did not alter plasma TXB(2) and 6-keto PGF(1alpha) concentrations. Deracoxib administration resulted in a minor abnormality in platelet aggregation. Anti-inflammatory doses of aspirin did not affect platelet function as measured by use of optical aggregometry and a platelet-function analyzer. Further evaluation of the effects of aspirin and cyclooxygenase-2-selective inhibitors on hemostasis should be performed.

A case of primary hypothyroidism causing central nervous system atherosclerosis in a dog.

A 2-year-old, castrated male, Australian shepherd was presented with a history of chronic mild ataxia, obesity, and lethargy. The dog was treated with levothyroxine, but the ataxia worsened. Cranial nerve abnormalities developed and the dog was euthanized. Postmortem examination revealed marked thyroid gland atrophy and widespread, severe central nervous system atherosclerosis.

Effects of doxycycline, amoxicillin, cephalexin, and enrofloxacin on hemostasis in healthy dogs.

OBJECTIVE: To determine the effects of enteral administration of doxycycline, amoxicillin, cephalexin, and enrofloxacin at therapeutic dosages for a typical duration on hemostatic variables in healthy dogs. ANIMALS: 14 Beagles. PROCEDURE: Doxycycline (10 mg/kg, PO, q 12 h), amoxicillin (30 mg/kg, PO, q 12 h), cephalexin (30 mg/kg, PO, q 12 h), and enrofloxacin (20 mg/kg, PO, q 24 h) were administered in random order to 10 healthy dogs at standard therapeutic dosages for 7 days, with a 7-day washout period between subsequent antimicrobials. In addition, 4 Beagles served as control dogs. Variables were evaluated before and after antimicrobial administration; they included platelet count, Hct, 1-stage prothrombin time (PT), activated partial thromboplastin time (PTT), fibrinogen concentration, and platelet function. Platelet function was assessed via buccal mucosal bleeding time, aggregation, and a platelet-function analyzer. RESULTS: Administration of all antimicrobials caused a slight prolongation of 1-stage PT and activated PTT and slight decrease in fibrinogen concentration. Cephalexin caused a significant increase in 1-stage PT and activated PTT, amoxicillin caused a significant increase in activated PTT, and enrofloxacin caused a significant decrease in fibrinogen concentration. Platelet count or function did not differ significantly after administration of any antimicrobial. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of commonly used antimicrobials in healthy dogs resulted in minor secondary hemostatic abnormalities, with no change in platelet count or function. Although these changes were clinically irrelevant in healthy dogs, additional studies of the effects of antimicrobial administration on hemostasis in animals with underlying disease processes are warranted.

Cutaneous manifestations of disseminated toxoplasmosis in an immunosuppressed dog.

A 3.5-year-old, castrated male, giant schnauzer was presented with alopecic pustular dermatitis. Immune-mediated hemolytic anemia had been diagnosed 45 days previously. At the time of presentation, the dog was receiving prednisone, azathioprine, and cyclosporine. Cutaneous protozoosis was diagnosed, and postmortem examination revealed protozoa within cutaneous, cardiac, pancreatic, and pulmonary tissues. The protozoa divided by endodyogeny, had the morphology of Toxoplasma gondii (T. gondii) tachyzoites, and stained positively with T. gondii polyclonal antibodies but not with antibodies to Neospora caninum or Sarcocystis neurona. Immunosuppression may have predisposed this dog to disseminated toxoplasmosis.

Effects of ranitidine, famotidine, pantoprazole, and omeprazole on intragastric pH in dogs.

OBJECTIVE: To identify the normal gastric acid secretion profile in dogs and determine the degree of gastric acid suppression associated with 4 gastric acid suppressants. ANIMALS: 12 healthy Beagles. PROCEDURE: Intragastric pH was measured continuously for 24-hour periods with a digital recording system placed via a gastrostomy tube. Baseline measurements were obtained when food was withheld and when dogs were fed a standard diet. Dogs were then treated with ranitidine (2 mg/kg, IV, q 12 h), famotidine (0.5 mg/kg, IV, q 12 h), pantoprazole (1 mg/kg, IV, q 24 h), omeprazole (1 mg/kg, PO, q 24 h), or saline solution for 7 days; intragastric pH was recorded on days 0, 2, and 6. Subsequently, the effects of administering famotidine (0.5 mg/kg, IV, q 8 h; 6 dogs) and omeprazole as a suspension (1 mg/kg, PO, q 12 h; 6 dogs) were evaluated. Median 24-hour intragastric pH, percentage of time pH was > or = 3, and percentage of time pH was > or = 4 were determined. RESULTS: Median pH, percentage of time pH was > or = 3, and percentage of time pH was > or = 4 were all significantly higher when food was withheld than when dogs were fed. Famotidine, pantoprazole, and omeprazole significantly suppressed gastric acid secretion, compared with saline solution, as determined on the basis of median 24-hour pH and percentages of time pH was > or = 3 or > or = 4. However, ranitidine did not. Omeprazole suspension suppressed gastric acid secretion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in healthy dogs, famotidine, pantoprazole, and omeprazole significantly suppress gastric acid secretion. Twice daily administration of a suspension of omeprazole, was the only regimen tested that approached the potential therapeutic efficacy for acid-related disease when assessed by criteria used for human patients.