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- Author or Editor: Miranda J. Sadar x
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Abstract
OBJECTIVE
To determine the pharmacokinetics of hydromorphone hydrochloride after IV and IM administration in guinea pigs (Cavia porcellus).
ANIMALS
8 healthy adult guinea pigs (4 sexually intact females and 4 sexually intact males).
PROCEDURES
In a crossover study, hydromorphone (0.3 mg/kg) was administered once IM (epaxial musculature) or IV (cephalic catheter) to each guinea pig at a 1-week interval (2 treatments/guinea pig). Blood samples were collected before and at predetermined intervals after drug administration via a vascular access port. Plasma hydromorphone concentrations were determined by liquid chromatography–tandem mass spectrometry. Noncompartmental analysis of data was used to calculate pharmacokinetic parameters.
RESULTS
Mean ± SD clearance and volume of distribution for hydromorphone administered IV were 52.8 ± 13.5 mL/min/kg and 2.39 ± 0.479 L/kg, respectively. Mean residence time determined for the IV and IM administration routes was 0.77 ± 0.14 hours and 0.99 ± 0.34 hours, respectively. The maximum observed plasma concentration following IM administration of hydromorphone was 171.9 ± 29.4 ng/mL. No sedative effects were observed after drug administration by either route.
CONCLUSIONS AND CLINICAL RELEVANCE
Pharmacokinetic data indicated that hydromorphone at a dose of 0.3 mg/kg may be administered IV every 2 to 3 hours or IM every 4 to 5 hours to maintain a target plasma concentration between 2 and 4 ng/mL in guinea pigs. Hydromorphone had high bioavailability after IM administration. Further research is necessary to evaluate the effects of other doses and administration routes and the analgesic effects of hydromorphone in guinea pigs.
Abstract
OBJECTIVE To determine pharmacokinetics and sedative effects of buprenorphine after IV and oral transmucosal (OTM) administration in guinea pigs.
ANIMALS 14 male guinea pigs (6 adults for preliminary experiment; eight 8 to 11-week-old animals for primary study).
PROCEDURES A preliminary experiment was conducted to determine an appropriate buprenorphine dose. In the primary study, buprenorphine (0.2 mg/kg) was administered IV or OTM, and blood samples were obtained. The pH of the oral cavity was measured before OTM administration. Sedation was scored for 6 hours on a scale of 0 to 3 (0 = no sedation and 3 = heavy sedation). After a 7-day washout period, procedures were repeated in a crossover manner. Plasma buprenorphine concentration was quantified, and data were analyzed with a noncompartmental pharmacokinetic approach.
RESULTS Mean peak plasma buprenorphine concentrations were 46.7 and 2.4 ng/mL after IV and OTM administration, respectively. Mean time to maximum plasma buprenorphine concentration was 1.5 and 71.2 minutes, and mean terminal half-life was 184.9 and 173.0 minutes for IV and OTM administration, respectively. There was a range of sedation effects (0 to 2) for both routes of administration, which resolved within the 6-hour time frame.
CONCLUSIONS AND CLINICAL RELEVANCE On the basis of pharmacokinetic parameters for this study, buprenorphine at 0.2 mg/kg may be administered IV every 7 hours or OTM every 4 hours to maintain a target plasma concentration of 1 ng/mL. Further studies are needed to evaluate administration of multiple doses and sedative effects in guinea pigs with signs of pain.
Abstract
OBJECTIVE To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis).
ANIMALS 7 adult nonreleasable healthy red-tailed hawks.
PROCEDURES In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed.
RESULTS Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 μg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 μg/mL and target plasma ceftiofur concentration of 4 μg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.
Abstract
CASE DESCRIPTION A 4-year-old sexually intact male pet guinea pig (Cavia porcellus) was evaluated for a routine wellness examination.
CLINICAL FINDINGS During physical examination, a small mass was palpated in the cranial aspect of the abdomen. Abdominal radiographic and ultrasonographic findings were suggestive of a gastric mass. Cytologic evaluation of a fine-needle aspirate of the mass was indicative of spindle cell proliferation most consistent with a sarcoma.
TREATMENT AND OUTCOME The patient was anesthetized, and an exploratory laparotomy and partial gastrectomy were performed to resect the gastric mass. Histologic and immunohistochemical examinations of the mass revealed that it was a gastric leiomyoma. The patient recovered from surgery without complications. No evidence of mass recurrence was observed during an abdominal ultrasonographic examination performed approximately 19 months after surgery.
CLINICAL RELEVANCE To our knowledge, this was the first report of the clinical diagnosis and successful surgical treatment of a gastric neoplasm in a guinea pig. Gastric leiomyomas are not uncommon in guinea pigs, and although benign, they can cause clinical signs if they become large enough to impair gastric function. Gastrointestinal surgery should be considered as a treatment option for guinea pigs with similar gastric neoplasms.
Abstract
In collaboration with the American College of Veterinary Pathologists
Abstract
OBJECTIVE
To retrospectively evaluate the prevalence and clinical progression of wobbly hedgehog syndrome (WHS) and concurrent incidence of neoplasia in a cohort of African pygmy hedgehogs (Atelerix albiventris).
ANIMALS
49 hedgehogs.
CLINICAL PRESENTATION AND PROCEDURES
Medical records of hedgehogs from 7 institutions across the US over a 20-year period (2000 to 2020) were retrospectively reviewed. Inclusion criteria were hedgehogs of any sex or age with postmortem CNS histopathology consistent with WHS. Collected data included sex, age at onset and euthanasia, major histopathologic findings, reported neurologic clinical signs, and treatments administered.
RESULTS
24 males and 25 females were included. Fifteen of 49 (31%) individuals had subclinical WHS with no reported antemortem neurologic clinical signs. In neurologically affected (clinical) hedgehogs (n = 34), the mean ± SD age at onset was 3.3 ± 1.5 years with a median (range) time from onset to euthanasia of 51 days (1 to 319 days). In neurologically affected hedgehogs, the most commonly reported clinical signs were ataxia (n = 21) and pelvic limb paresis (16) and the most commonly administered treatment was meloxicam (13). Overall, 31 of 49 (63%) hedgehogs had a concurrent histopathologic diagnosis of neoplasia outside of the CNS.
CLINICAL RELEVANCE
The prognosis for hedgehogs with WHS is poor. No treatment had a significant effect on survival time, and neoplasia was a common comorbidity in the current cohort. A small but clinically relevant subset of neurologically normal hedgehogs had a histopathologic diagnosis of WHS.
