High-concentration buprenorphine exceeds target plasma concentrations for extended periods following subcutaneous administration in American flamingos (Phoenicopterus ruber).

OBJECTIVE: To determine the pharmacokinetic parameters of a high-concentration buprenorphine formulation after a single SC dose in American flamingos (Phoenicopterus ruber). ANIMALS: 6 healthy adult American flamingos (3 males and 3 females). METHODS: A single dose of high-concentration buprenorphine (1.8 mg/kg) was administered SC to all birds. Blood samples were collected at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, and 96 hours after drug administration between October 14 and October 18, 2022. Plasma buprenorphine concentrations were determined by liquid chromatography-tandem mass spectrometry and a noncompartmental analysis was used to determine pharmacokinetic parameters. RESULTS: Mean ± SD peak plasma drug concentration (Cmax) was 195.1 ± 187.4 ng/mL, the mean time to peak plasma concentration (Tmax) was 0.32 ± 0.31 hours, the mean area under the concentration-vs-time curve from time 0 to the last measured concentration (AUC0-last) was 881.4 ± 205.4 ng/mL, and mean terminal half-life (t1/2) was 12.6 ± 3.86 hours. Mean plasma buprenorphine concentrations were >1 ng/mL for at least 48 hours after drug administration. No clinically significant adverse effects were observed. CLINICAL RELEVANCE: High-concentration buprenorphine dosed at 1.8 mg/kg SC in American flamingos rapidly exceeded plasma drug concentrations reported to have analgesic effects in other avian species and maintained these levels for extended periods. Sedative effects were similar to those reported for other species. Additional studies are needed to evaluate the clinical efficacy of high-concentration buprenorphine at this dose in American flamingos.

Measurement of Cyclooxygenase Products in Plasma as Markers for Inhibition of Cyclooxygenase Isoforms by Oral Meloxicam in New Zealand White Rabbits (Oryctolagus cuniculus ).

Pain management in rabbits is a challenging task that is complicated by the rabbit's ability to hide signs of distress and the limited pharmacologic data available for this species. Pharmacokinetic data has shown that in rabbits, meloxicam, a nonsteroidal anti-inflammatory NSAID, reaches plasma concentrations that are known to provide analgesia in dogs and cats; these concentrations could theoretically alleviate pain in rabbits. However, the inhibitory effects of meloxicam on cyclooxygenase (COX) isoforms have not been studied in rabbits. In this study, we measured the products of COX-1 and COX-2 after the oral administration of a single 1 mg/kg dose of meloxicam to New Zealand White rabbits (n = 6). Blood samples were collected before drug administration (T0) and then at predetermined time points over 48 h. Plasma prostaglandin E2 (PGE2 ) and thromboxane (TxB2) concentrations were measured as surrogate markers for COX-1 and COX-2, respectively, by using commercial ELISA kits. After meloxicam administration, both TxB2 and PGE2 plasma concentrations fell significantly below baseline, with maximal mean reductions to 80% and 60% of baseline at 8 h, respectively. The reduction in PGE2 concentrations was followed by a significant increase that moved its mean plasma concentrations toward baseline between 8 and 24 h. Adverse effects such as lethargy, inappetence, or changes in fecal production were not observed in any rabbits. In conclusion, meloxicam appeared to significantly inhibit both COX-1 and COX-2 with a time course similar to previously reported meloxicam plasma concentration-time profiles in rabbits. Our data suggest that a dosage of 1 mg/kg given orally could provide analgesia to rabbits, but a more frequent dosing interval than the currently recommended daily dosing may be required to maintain clinical efficacy.

A three-portal laparoscopic hysterectomy in a chimpanzee (Pan troglodytes) with a uterine manipulator and vessel sealing device.

OBJECTIVE: To report the treatment and outcome of a a captive chimpanzee (Pan troglodytes) undergoing 3-portal laparoscopic hysterectomy. Additionally, the technique used for successful urinary catheterization is described. ANIMALS: A 29-year-old female intact chimpanzee with uterine bleeding. STUDY DESIGN: Clinical case report. METHODS: Uterine changes consistent with adenomyosis and/or endometriosis were noted on abdominal ultrasonographic and computed tomographic examinations. A urinary catheter was placed before a 3-portal laparoscopic hysterectomy with a uterine manipulator (VCare) and a vessel sealer (Ligasure). The uterus was submitted for histopathology. RESULTS: Preoperative urinary catheterization was achieved with several modifications and prevented bladder protrusion into the surgical field. Laparoscopy provided excellent visualization of the pelvic structures and VCare effectively maneuvered the uterus for a safe and efficient dissection. The use of the vessel sealer was effective, and bleeding was minimal. Anesthesia and surgery lasted 240 and 150 minutes, respectively. No complications were encountered. Histopathological changes of the uterus were consistent with adenomyosis and myometrial hyperplasia. The chimpanzee recovered uneventfully and returned to normal behavior with no recurrence of uterine bleeding 5 months after surgery. CONCLUSION: The 3-portal laparoscopic technique reported here allowed hysterectomy without complication in this chimpanzee. Urinary catheterization was technically challenging but successful.