Pharmacokinetics of Trazodone in Hispaniolan Parrots (Amazona ventralis).

The objective of this study was to establish the pharmacokinetics of a single oral dose of trazodone in the Hispaniolan Amazon parrot (Amazona ventralis). Trazodone is a selective serotonin antagonist and reuptake inhibitor used commonly in both human and veterinary medicine as an antidepressant behavioral modification medicine. A single oral dose of compounded trazodone hydrochloride solution (20 mg/mL) at 50 mg/kg was administered to a total of 7 healthy adult Hispaniolan Amazon parrots. The 7 healthy adult parrots ranged in age from 10 to 15 years and weighed 228 to 323g. Blood was collected at baseline (2 weeks before study) and at 1, 2, 4, 6, 10, and 14 hours post-drug administration. Plasma concentrations of both trazodone and its active metabolite m-chlorophenylpiperazine (mCPP) were measured via liquid chromatography tandem mass spectrometry. Noncompartmental pharmacokinetic analysis was completed. The half-life (t1/2) ± SD of trazodone for the Hispaniolan parrots was 1.89 ± 0.49 hours, and the t1/2 ± SD of mCPP metabolite was 1.9 ± 0.55 hours. Maximum serum drug concentrations, or Cmax (ng/mL), were 738.3 ± 285.3 for trazodone. Times to achieve Cmax (hours) for trazadone and the mCPP metabolite were 1 hour and 2 hours postdosing, respectively. While this study did not establish the behavioral effects of trazodone, no adverse side effects were observed throughout the 48-hour period following drug administration and blood collection. Our results indicate that the oral administration of a 50-mg/kg single dose of trazodone to Hispaniolan parrots may be considered a safe dose. Plasma concentrations are comparable to previously published values in humans, dogs, horses, and pigeons (Columba livia domestica) for up to 14 hours following dosing. This study indicates that further studies are needed to establish the pharmacodynamics and the efficacy of trazodone in the medical management of behavioral problems in psittacine species.

Reference Interval Creation for Symmetric Dimethylarginine (SDMA) in Healthy Hispaniolan Amazon Parrots (Amazona ventralis) and Quaker Parrots (Myiopsitta monachus).

Renal disease is often identified as a cause of morbidity and mortality in avian patients. However, currently, early antemortem detection of renal disease in avian patients is difficult. Anatomical and physiological differences between mammals and birds mean the use of commonly employed diagnostic testing (ie, measurement of blood urea nitrogen [BUN] and serum creatinine, urinalysis, and ultrasonography) are either nondiagnostic or difficult to achieve. Symmetric dimethylarginine (SDMA) is considered a more sensitive marker for renal disease in humans, dogs, and cats. However, SDMA has not yet been assessed for diagnostic use in any psittacine species. In this study, we establish reference ranges for SDMA in both Hispaniolan Amazon parrots (Amazona ventralis, HAP) and Quaker parrots (Myiopsitta monachus, QP). Blood was collected from 23 Amazon parrots and 32 Quaker parrots maintained in research facilities. Measurement of SDMA through a commercially available immunoassay (IA-SDMA) as well as creatinine, BUN, uric acid, phosphorus, calcium, sodium, potassium, and chloride were determined through IDEXX Laboratories. Plasma SDMA concentrations ranged from 6 to 15 µg/dL and 3 to 15 µg/dL for the HAP and QP, respectively. Sex was a confounding factor for the QP population, but sex did not have a significant effect on SDMA for the HAP population. No significant correlations were identified between SDMA concentrations and other parameters in either psittacine species. Our results show proof of concept for the IA-SDMA and provide reference intervals for SDMA in HAP and QP. Further investigation is required to determine the validity of this assay and the predictive power of SDMA in the detection of renal impairment for parrots and other common companion birds.

Measuring the Level of Agreement for Lactate Measurements in Hispaniolan Amazon Parrots (Amazona ventralis) Among 2 Point-of-Care Analyzers and a Benchtop Analyzer.

Lactate is an important biochemistry analyte used in human and veterinary medicine to assess tissue perfusion and can be used as a prognostic indicator for certain disease conditions. Whereas lactate is commonly measured using "patient-side" handheld meters, these meters have not been validated for companion avian species. The purpose of this study was to measure the level of agreement between 2 commercially available point-of-care lactate meters and a laboratory benchtop blood analyzer in Hispaniolan Amazon parrots (Amazona ventralis). Blood samples were collected from 20 adult parrots at Louisiana State University by drawing 1.5 mL of blood from the right jugular vein. One drop of whole blood was used for the Lactate Plus analyzer and the remainder of the sample transferred into a lithium heparin microtainer. From the blood in the microtainer, 0.2 mL whole blood was analyzed using the epoc Blood Analysis System, and the remaining sample was centrifuged to obtain plasma that was immediately frozen at -80°C (-112°F) and submitted to the Texas A&M University Clinical Pathology Laboratory for analysis on the VITROS 4500 benchtop analyzer. Bland-Altman agreement plots and Passing-Bablok regression were used to measure the level of agreement between the methods. There was poor agreement between all 3 methods with mean percentage differences in lactate concentrations ≥22% (epoc and Lactate Plus: 33.6% [95% CI: 27-40]; epoc and VITROS 4500: 55% [95% CI:52-58]; VITROS 4500 and Lactate Plus: 22% [95% CI:16-28]). Based on these results, the point-of-care meters tested in this study are not interchangeable, and separate reference intervals were calculated for each method. Blood lactate concentrations may have more utility in tracing lactate trends over time in an individual rather than being able to utilize this information at 1 time point for disease diagnosis and prognosis.

Evaluation of Prothrombin Time and Activated Partial Thromboplastin Time in Native and Citrated Whole Blood in Hispaniolan Amazon Parrots (Amazona ventralis) With a Handheld Point-of-Care Analyzer.

Objective assessment of coagulation in birds is difficult, and traditional methods of measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT) with the use of mammalian reagents have not been validated in birds. Avian-specific reagents must be prepared from brain extract and are not practical for clinical use. The objective of this investigation was to determine whether the InSight qLabs point-of-care analyzer (Micropoint Biotechnologies Inc, Guangdong, China) could measure PT and aPTT in Hispaniolan Amazon parrots (Amazona ventralis) in native and citrated whole blood, and whether the values obtained correlated with clinical appearance and basic hematologic and biochemical parameters from the bird. The qLabs analyzer was able to measure aPTT reliably, but not PT. Activated partial thromboplastin time of citrated blood was significantly different from the aPTT measured from native whole blood (P < 0.001). On the basis of this study, the qLabs machine may be used to measure aPTT, but clinical application between avian species requires further research.

Pharmacokinetics of Cannabidiol in the Hispaniolan Amazon Parrot (Amazona ventralis).

The purpose of this study was to determine the pharmacokinetics of cannabidiol (CBD), a potential treatment option that may alleviate pain in companion animals and humans, in the Hispaniolan Amazon parrot (Amazona ventralis). A pilot study administered a single oral dose of CBD in hemp oil at 10 mg/kg to 2 birds and 20 mg/kg to 2 birds. Because the maximum serum concentrations (Cmax) for these doses were 5.5 and 13 ng/mL, respectively, and the serum half-life was 2 hours for both groups, the doses were considered too low for clinical use in this species. Therefore, a study was designed in which 14 healthy 12-14-year-old parrots of both sexes and weighing 0.24-0.35 kg (mean, 0.28 kg) were enrolled. Seven birds were administered 60 mg/kg CBD PO, and 7 birds were administered 120 mg/kg CBD PO. Blood samples were obtained at time 0, and at 0.5, 1, 2, 3, 4, 6, and 10 hours posttreatment in a balanced incomplete block design. Quantification of plasma CBD concentrations was determined by use of a validated liquid chromatography-mass spectrometry assay. Pharmacokinetic parameters were determined by noncompartmental analysis. The areas under the curve (h·ng/mL) were 518 and 1863, Cmax (ng/ mL) were 213 and 562, and times to achieve Cmax (hours) were 0.5 and 4 for the 60 and 120 mg/kg doses, respectively. The serum half-life could not be determined in the 60 mg/kg treatment, but was 1.28 hours at 120 mg/kg. Adverse effects were not observed in any bird. The highly variable results and short half-life of the drug in Hispaniolan Amazon parrots, even at high doses, suggests that this drug formulation was inconsistent in achieving targeted concentrations as reported in other animal species.

Evaluation of a Fluoroscopic Angiography Protocol in Hispaniolan Amazon Parrots (Amazona ventralis).

Fluoroscopic angiography evaluates the heart and vascular tree in real time and can be recorded for further diagnostic analysis and measurements. Although reports have been published of the use of fluoroscopic angiography in birds, this technique has not been evaluated in any avian species. The purpose of this study was to evaluate a fluoroscopic angiography protocol in 12 adult Hispaniolan Amazon parrots (Amazona ventralis). Under general anesthesia, the birds were positioned in right lateral (LAT) recumbency on a fluoroscopy table. A bolus of nonionic iodinated contrast agent was injected through a catheter inserted into the basilic or medial metatarsal vein during video acquisition. The same bolus was repeated to obtain the ventrodorsal (VD) view with the bird placed in dorsal recumbency. Eleven studies were performed. A total of 19 (10 VD, 9 LAT) continuous, real-time, fluoroscopic angiograms were successfully captured. The brachiocephalic trunk, aorta, pulmonary arteries, pulmonary veins, and caudal vena cava were visualized, and selected intraluminal measurements collected. The intraobserver and interobserver variability for 3 observers was calculated. Intraobserver agreement was found to be near perfect (intraclass correlation coefficient ≥0.95), whereas interobserver agreement was moderate to substantial (intraclass correlation coefficient ≥0.52). Coefficients of variation were excellent (VD 0.99, LAT 0.99) for intraobserver assessments and moderate (VD 0.72, LAT 0.52) for interobserver assessments. For the interobserver assessments, the VD projection measurements performed better than the LAT measurements. These results suggest that although there was some variation between different observers, relatively consistent vascular measurements could be obtained. The described fluoroscopic angiography protocol is a repeatable and reliable technique that could be useful for the diagnosis and monitoring of cardiovascular diseases in birds.

Pilot Study of a Single Dose of Orally Administered Tapentadol Suspension in Hispaniolan Amazon Parrots (Amazona ventralis).

Tapentadol is an analgesic agent that acts as both a µ-opioid receptor agonist and a norepinephrine reuptake inhibitor. It is a common therapeutic agent in human medicine for management of acute and chronic pain, and it is currently being investigated for use in veterinary medicine. Tapentadol was evaluated in Hispaniolan Amazon parrots (Amazona ventralis) because there is only 1 other oral opioid-like analgesic agent, tramadol, which has been evaluated in an avian species. The effectiveness of tramadol after administration to a patient involves a complex physiologic metabolism and has been found to have variable pharmacokinetics between species. Because of the lack of active metabolites from tapentadol, less interspecific variation was expected. Seven Hispaniolan Amazon parrots were used to evaluate the pharmacokinetics of tapentadol after a single 30 mg/kg PO administration of a compounded 5 mg/mL tapentadol suspension. Blood samples were collected before (time 0) and 0.25, 0.5, 0.75, 1, 1.5, 3, and 6 hours after administration, following a balanced, incomplete-block design. Plasma tapentadol concentrations were measured by high-pressure liquid chromatography with mass spectrometry. Results revealed detectable plasma concentrations in only 2 of 7 birds (29%), and the bird with the highest plasma levels had a peak concentration (Cmax) of 143 ng/mL and a half-life (T 1/2) of 24.8 minutes. The variable plasma concentrations and short half-life of this drug in Hispaniolan Amazon parrots suggests that this drug would be of limited clinical use in this species; however, it is possible that this drug will be more bioavailable in other avian species.

Evaluation of Orally Administered Atorvastatin on Plasma Lipid and Biochemistry Profiles in Hypercholesterolemic Hispaniolan Amazon Parrots (Amazona ventralis).

Atorvastatin is a synthetic statin administered in its active form and used for the treatment of dyslipidemias. In the current study, the effects of atorvastatin were evaluated on plasma lipid profiles and the potential for adverse effects after once daily PO dosing of atorvastatin for 30 days in Hispaniolan Amazon parrots (Amazona ventralis). Sixteen adult parrots (10 female, 6 male) with hypercholesterolemia were used for this study. Birds were assigned to 2 groups (treatment and control) of 8 parrots each (3 male, 5 female) after balancing for age, sex, originating institution, and baseline plasma cholesterol values. Compounded atorvastatin oral suspension (10 mg/kg) was administered PO once daily via gavage into the crop. Equivalent volumes of placebo suspension were administered to the control group. Plasma biochemistry and plasma lipid profile analysis (total cholesterol, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides [TGs]) were analyzed on days 0, 14, and 30. Plasma samples and HDL-C fractions were evaluated for cholesterol and TG concentrations via enzymatic assays. Subtraction of HDL-C values from total cholesterol yielded the non-HDL-C concentration for each bird. Birds were routinely assessed for appetite, activity, and urofeces. Plasma atorvastatin concentrations were obtained from 7 of 8 birds in the treatment group from banked samples. Those samples were obtained on days 14 and 30, with drug administration 6 to 8 hours before collection. No significant differences were observed in total cholesterol, HDL-C, non-HDL-C, or TG between treatment and control groups at days 0, 14, and 30. Plasma atorvastatin concentrations were variable on day 14 (0.54-5.41 ng/ mL for 6 of 7 samples, with 1 outlier of 307 ng/mL) and on day 30 (0.79-6.74 ng/mL). No adverse effects were noted in any of the birds during the study period. When dosed PO at 10 mg/kg once daily, atorvastatin did not result in significant changes to plasma lipid profiles (eg, lowering of plasma total or non-HDL-C concentrations) at any time point during this study. Future studies to investigate pharmacokinetic and pharmacodynamic properties of atorvastatin in parrots may require increased doses and/or frequency of administration.

Effects of Fluorescent Lighting Versus Sunlight Exposure on Calcium, Magnesium, Vitamin D, and Feather Destructive Behavior in Hispaniolan Amazon Parrots (Amazona ventralis).

Low exposure to ultraviolet light, and resulting vitamin D deficiency, has recently been linked to autism spectrum disorder in people. Captive psittacine birds that exhibit feather destructive behavior share similarities with people affected by autism spectrum disorder, such as repetitive (stereotypies) and self-harming behaviors. The metabolic and psychological effects of housing pet parrots indoors without ultraviolet B lighting are not typically considered in animal husbandry or veterinary care. Calcifediol (serum vitamin D), ionized calcium, and ionized magnesium levels were compared between 10 Hispaniolan Amazon parrots (Amazona ventralis) housed indoors and 10 Hispaniolan Amazon parrots historically housed outdoors. Although ionized calcium and magnesium levels were not significantly different, calcifediol levels were significantly greater in the colony of birds housed outdoors. Further, these 2 research colonies of individually housed birds were feather scored. Subjectively, the birds that were housed indoors had greater self-inflicted feather damage than did those housed outdoors; however, the difference was not statistically significant.

EFFECT OF ROUTINE HANDLING AND TRANSPORTATION ON BLOOD LEUKOCYTE CONCENTRATIONS AND PLASMA CORTICOSTERONE IN CAPTIVE HISPANIOLAN AMAZON PARROTS ( AMAZONA VENTRALIS).

Increased glucocorticoids cause a characteristic stress leukogram in mammalian taxa. It is assumed that avians exhibit a similar response, but to date, there have been no controlled studies to correlate serial endogenous corticosterone levels to hematologic values. An established flock of 18 Hispaniolan Amazon parrots ( Amazona ventralis) was used as a model in a crossover study. The treatment group was subjected to the stress of transport, restraint, and common clinical procedures with serial blood samples collected at 20-min intervals for hematology and corticosterone levels; the control group was sampled at the same intervals. Longitudinal data analysis was performed with linear mixed modeling. For all hematologic analytes, the baseline value had a significant positive effect on subsequent values (all P < 0.001). The white blood cell, heterophil, and eosinophil counts and heterophil to lymphocyte ratio increased over time in the treatment group, whereas it remained stable in the control group ( P = 0.016, P < 0.001, P < 0.001, P = 0.02, respectively, for the time*treatment effect). Lymphocyte absolute counts decreased over time, although not significantly; the decrease was significant for the relative lymphocyte count in the treatment group. Monocytes and basophils were not significantly altered. The treatment group had a higher mean corticosterone level overall than the control group by approximately 60% ( P = 0.008). The mean corticosterone level also increased over time in both groups by three- to fourfold ( P < 0.001) by 20 min then plateaued. These results demonstrate that some significant hematologic changes may arise with routine handling and transportation of birds and should be accounted for in hematologic interpretation of cell counts.

Pharmacokinetics of a Sustained-release Formulation of Meloxicam After Subcutaneous Administration to Hispaniolan Amazon Parrots (Amazona ventralis).

Meloxicam has been shown to have a safe and favorable pharmacodynamic profile with individual variability in Hispaniolan Amazon parrots (Amazona ventralis). In the current study, we determined the pharmacokinetics of a sustained-release formulation of meloxicam after subcutaneous administration to Hispaniolan Amazon parrots. Twelve healthy adult parrots, 6 males and 6 females, were used in the study. Blood samples were collected before (time 0) and at 0.5, 1, 2, 6, 12, 24, 48, 72, 96, and 120 hours after a single dose of the sustained-release meloxicam formulation (3 mg/kg SC). Plasma meloxicam concentrations were measured by high-pressure liquid chromatography. Pharmacokinetic parameters were determined by noncompartmental analysis. Plasma concentrations reached a mean Cmax of 23.4 µg/mL (range, 14.7-46.0 µg/mL) at 1.8 hours (range, 0.5-6 hours), with a terminal half-life of 7.4 hours (range, 1.4-40.9 hours). Individual variation was noticeable, such that some parrots (4 of 12 birds) had very low plasma meloxicam concentrations, similar to the high variability reported in a previous pharmacokinetic study of the standard meloxicam formulation in the same group of birds. Two birds developed small self-resolving scabs at the injection site. On the basis of these results, the sustained-release meloxicam formulation could be administered every 12 to 96 hours in Hispaniolan Amazon parrots to manage pain. Because of these highly variable results, the use of this formulation in this species cannot be recommended until further pharmacokinetic, safety, and pharmacogenomic evaluations are performed to establish accurate dosing recommendations and to understand the high pharmacokinetic variability.

Single-Dose Pharmacokinetics of Piperacillin/Tazobactam in Hispaniolan Amazon Parrots ( Amazona ventralis ).

To determine the pharmacokinetics of piperacillin/tazobactam in Hispaniolan Amazon parrots ( Amazona ventralis ), 8 healthy adult parrots of both sexes were used in a 2-part study. In a pilot study, piperacillin (87 mg/kg) in combination with tazobactam (11 mg/kg) was administered intramuscularly (IM) to 2 birds, and blood samples were obtained at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 10 hours after administration. Based on the results obtained, a main study was done in which piperacillin/tazobactam was administered at 2 different doses. In 3 birds, the initial dose of piperacillin (87 mg/kg)/tazobactam (11 mg/kg) IM was administered, and in 3 birds, the dose was doubled to piperacillin (174 mg/kg)/tazobactam (22 mg/kg) IM. In all 6 birds, blood samples were obtained at 0, 5, 15, and 30 minutes and at 1, 1.5, 2, 2.5, 3, and 4 hours after administration. Quantification of plasma piperacillin and tazobactam concentrations was determined by validated liquid chromatography-mass spectrometry assay. Pharmacokinetic parameters were determined by noncompartmental analysis. After intramuscular administration, the mean ± standard error values of T1/2 (h) was 0.52 ± 0.05 and 0.32 ± 0.07, Tmax (h) was 0.28 ± 0.09 and 0.25 ± 0.10, Cmax (µg/mL) was 86.34 ± 20.62 and 9.03 ± 2.88, and Cmax/dose was 0.99 ± 0.24 and 0.83 ± 0.26 for piperacillin (87 mg/kg) and tazobactam (11 mg/kg), respectively. When the doses were doubled, the T1/2 (h) was 0.65 ± 0.08 and 0.34 ± 0.02, Tmax (h) was 0.28 ± 0.12 and 0.14 ± 0.06, Cmax (µg/mL) was 233.0 ± 6.08 and 22.13 ± 2.35, and Cmax/dose was 1.34 ± 0.03 and 1.02 ± 0.11 for piperacillin and tazobactam, respectively. Results indicate that piperacillin is rapidly absorbed and reaches high initial concentrations; however, it is also rapidly eliminated in the Hispaniolan Amazon parrot, and tazobactam has similar pharmacokinetics as piperacillin. Administration of piperacillin at 87 mg/kg IM q3-4h is recommended for this species to control infections attributed to susceptible bacteria with a minimum inhibitory concentration of ≤4 µg/mL.

EFFECTS OF EXERCISE ON THE PLASMA LIPID PROFILE IN HISPANIOLAN AMAZON PARROTS (AMAZONA VENTRALIS) WITH NATURALLY OCCURRING HYPERCHOLESTEROLEMIA.

Hypercholesterolemia is common in psittacines, and Amazon parrots ( Amazona spp.) are particularly susceptible. Associations have been demonstrated between naturally occurring and experimentally induced hypercholesterolemia and atherosclerosis in psittacines. Daily exercise improves lipid metabolism in humans and other mammals, as well as pigeons and chickens, under varying experimental conditions. Hispaniolan Amazon parrots ( Amazona ventralis ) with naturally occurring hypercholesterolemia (343-576 mg/dl) were divided into two groups. An exercised group (n = 8) was housed as a flock and exercised daily with 30 min of aviary flight and 30 min walking on a rotating perch. A sedentary control group (n = 4) was housed in individual cages with no exercise regime. A plasma lipid panel, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and triglycerides, was validated for this species. Body weight, chest girth, and the lipid panel were measured at 0, 61, and 105 days. Hematology and plasma biochemistry were measured at 0 and 105 days. Weight and girth were significantly lower in exercised than sedentary parrots at 61 and 105 days. HDL-C concentrations were significantly higher in exercised parrots at 61 days but returned to near baseline by 105 days. There were no significant changes in hematology, biochemistry, or other lipid panel parameters. Results were similar to studies in humans and animal models, in which increased HDL-C was the most consistent effect of exercise on circulating lipid and lipoprotein parameters. The return toward baseline HDL-C may have resulted from decreased participation in aviary flight. Additional investigation will be required to determine the amount of exercise and change in circulating lipid-related parameters necessary to improve long-term wellness in psittacine species predisposed to hypercholesterolemia.

The Efficacy and Safety of Topical Rocuronium Bromide to Induce Bilateral Mydriasis in Hispaniolan Amazon Parrots ( Amazona ventralis ).

The efficacy and safety of topically applied rocuronium in Hispaniolan Amazon parrots ( Amazona ventralis ) was assessed in a group of 10 adult birds. A complete ophthalmic examination (including Schirmer tear test, ocular reflexes, applanation tonometry, fluorescein staining, and slit-lamp biomicroscopy) was performed, and rocuronium bromide (0.15 mg in both eyes) was administered. Pupillary light reflex (PLR) and pupillary diameter were recorded in a darkened room at the following time points: 0, 10, 20, 30, 40, 50, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 300, and 360 minutes, and 24 hours. Fluorescein staining in both eyes was performed at 24 hours. By 10 minutes, PLR was absent in all birds (at 5 minutes, 8 birds; at 10 minutes, remaining 2 birds). Pupil diameter differed significantly from baseline at all time points. Additionally, PLR was decreased in 7/10 birds at 360 minutes and normal in all birds at 24 hours. Superficial corneal ulceration was observed at 24 hours in the left eye of 2/10 of the birds after fluorescein stain application. This study demonstrated that rocuronium bromide was an effective mydriatic agent in Hispaniolan Amazon parrots with rapid onset and prolonged duration of action.

Complete mitochondrial genome of the greater Antillean parrot Amazona ventralis (Hispaniolan amazon).

Androglossini is one of the four tribes recognized within the group of neotropical parrots. The tribe includes 10 genera of which Amazona genus is presently represented by about 30 species. The number of species may increase in the future because paraphyly of some Amazona species was recently demonstrated and some subspecies were proposed to be elevated to the species rank. Evolutionary history of Amazona genus also remains unresolved because published phylogenies suggest contradictory scenarios concerning directions of islands-mainland colonization. Therefore, we sequenced mitogenome of Amazona ventralis from Greater Antilles to gain molecular data essential in future examination of this genus diversification.

Pharmacokinetics of Compounded Intravenous and Oral Gabapentin in Hispaniolan Amazon Parrots ( Amazona ventralis ).

Neuropathic pain is a manifestation of chronic pain that arises with damage to the somatosensory system. Pharmacologic treatment recommendations for alleviation of neuropathic pain are often multimodal, and the few reports communicating treatment of suspected neuropathic pain in avian patients describe the use of gabapentin as part of the therapeutic regimen. To determine the pharmacokinetics of gabapentin in Hispaniolan Amazon parrots ( Amazona ventralis ), compounded gabapentin suspensions were administered at 30 mg/kg IV to 2 birds, 10 mg/kg PO to 3 birds, and 30 mg/kg PO to 3 birds. Blood samples were collected immediately before and at 9 different time points after drug administration. Plasma samples were analyzed for gabapentin concentration, and pharmacokinetic parameters were calculated with both a nonlinear mixed-effect approach and a noncompartmental analysis. The best compartmental, oral model was used to simulate the concentration-time profiles resulting from different dosing scenarios. Mild sedation was observed in both study birds after intravenous injection. Computer simulation of different dosing scenarios with the mean parameter estimates showed that 15 mg/kg every 8 hours would be a starting point for oral dosing in Hispaniolan Amazon parrots based on effective plasma concentrations reported for human patients; however, additional studies need to be performed to establish a therapeutic dose.

Thromboelastography Values in Hispaniolan Amazon Parrots ( Amazona ventralis ): A Pilot Study.

Thromboelastography (TEG) provides a global assessment of coagulation, including the rate of clot initiation, clot kinetics, achievement of maximum clot strength, and fibrinolysis. Thromboelastography (TEG) is used with increasing frequency in the field of veterinary medicine, although its usefulness in avian species has not been adequately explored. The purpose of this preliminary study was to assess the applicability of TEG in psittacine birds. Kaolin-activated TEG was used to analyze citrated whole blood collected routinely from 8 healthy adult Hispaniolan Amazon parrots ( Amazona ventralis ). The minimum and maximum TEG values obtained included time to clot initiation (2.6-15 minutes), clot formation time (4.3-20.8 minutes), α angle (12.7°-47.9°), maximum amplitude of clot strength (26.3-46.2 mm), and percentage of lysis 30 minutes after achievement of maximum amplitude (0%-5.3%). The TEG values demonstrated comparative hypocoagulability relative to published values in canine and feline species. Differences may be explained by either the in vitro temperature at which TEG is standardly performed or the method of activation used in this study. Although TEG may have significant advantages over traditional coagulation tests, including lack of need for species-specific reagents, further evaluation is required in a variety of avian species and while exploring various TEG methodologies before this technology can be recommended for use in clinical cases.

Plasma Drug Concentrations of Orally Administered Rosuvastatin in Hispaniolan Amazon Parrots (Amazona ventralis).

Atherosclerotic diseases are common in pet psittacine birds, in particular Amazon parrots. While hypercholesterolemia and dyslipidemia have not definitely been associated with increased susceptibility to atherosclerosis in parrots, these are important and well-known risk factors in humans. Therefore statin drugs such as rosuvastatin constitute the mainstay of human treatment of dyslipidemia and the prevention of atherosclerosis. No pharmacologic studies have been performed in psittacine birds despite the high prevalence of atherosclerosis in captivity. Thirteen Hispaniolan Amazon parrots were used to test a single oral dose of 10 mg/kg of rosuvastatin with blood sampling performed according to a balanced incomplete block design over 36 hours. Because low plasma concentrations were produced in the first study, a subsequent pilot study using a dose of 25 mg/kg in 2 Amazon parrots was performed. Most plasma samples for the 10 mg/kg dose and all samples for the 25 mg/kg dose had rosuvastatin concentration below the limits of quantitation. For the 10 mg/kg study, the median peak plasma concentration and time to peak plasma concentration were 0.032 µg/mL and 2 hours, respectively. Our results indicate that rosuvastatin does not appear suitable in Amazon parrots as compounded and used at the dose in this study. Pharmacodynamic studies investigating lipid-lowering effects of statins rather than pharmacokinetic studies may be more practical and cost effective in future studies to screen for a statin with more ideal properties for potential use in psittacine dyslipidemia and atherosclerotic diseases.

Pharmacokinetics of Levetiracetam in Healthy Hispaniolan Amazon Parrots ( Amazona ventralis ) After Oral Administration of a Single Dose.

Long-term anticonvulsive treatments have been poorly described in birds, and few pharmacokinetic studies have been performed, with mixed results. Levetiracetam, a new anticonvulsive drug, has shown good efficacy for monotherapy or adjunctive treatment of seizures in both human and veterinary medicine. To determine pharmacokinetics of levetiracetam in Hispaniolan Amazon parrots ( Amazona ventralis ), 20 healthy birds were randomly divided into 2 groups and administered either a 50 mg/kg (n = 10) or a 100 mg/kg (n = 10) oral dose of levetiracetam with no observable adverse effects. Blood samples were collected at baseline and at 12 time intervals (6 per group) for 16 hours. The concentration-time profiles resembled characteristic absorption, with maximum plasma concentrations of 61.0 µg/mL and 95.1 µg/mL at 60 minutes; terminal half-lives at 2.38 and 2.37 hours; volumes of distribution of 0.807 and 0.773 L/kg, with an area under the curve at 14 100 and 28 820 mg × min/L; and clearance rates of 3.65 and 3.60 mL/min per kg, respectively. Plasma concentrations were greater than 5.5 mg/L for up to 9.4 and 12 hours, suggesting an 8- and 12-hour oral dosing at 50 and 100 mg/kg, respectively, would be sufficient to maintain targeted values. Clinically, doses and frequencies may need escalation based on differences in species and individuals, and drug levels should be monitored.

Measuring the Level of Agreement Between Cloacal Gram's Stains and Bacterial Cultures in Hispaniolan Amazon Parrots ( Amazona ventralis ).

Cloacal or fecal Gram's stains and bacterial cultures are routinely performed during avian physical examinations to assess the microbial flora of the gastrointestinal tract. Although cloacal or fecal Gram's stains and bacterial cultures are considered routine diagnostic procedures, the level of agreement between the individual tests has not been determined. To investigate the level of agreement between results from Gram's stain and bacterial culture when used to assess cloacal or fecal samples from psittacine birds, samples were taken from 21 clinically healthy Hispaniolan Amazon parrots ( Amazona ventralis ) and tested by Gram's stain cytology and bacterial culture. Most bacteria (97.2%) identified by Gram's stain were gram positive. However, gram-negative organisms were identified in 7 of 21 (33.3%; 95% confidence interval: 13.3%-53.3%) birds. Escherichia coli was the only gram-negative organism identified on culture. Agreement between results of Gram's stain and culture was fair (weighted κ = 0.27). The results of this study suggest that Gram's stains and bacterial culture may need to be performed with a parallel testing strategy to limit the likelihood of misclassifying the microbial flora of psittacine patients.