Pharmacokinetics of intravenous ketorolac in cats undergoing gonadectomy

Pharmacokinetics of ketorolac in juvenile loggerhead sea turtles (Caretta caretta) after a single intramuscular injection

Ketorolac is a non-steroidal anti-inflammatory drug administered as an analgesic in humans. It has analgesic effects comparable to opioids but without adverse effects such as respiratory depression or restrictions because of controlled drug status. We designed this study to examine the potential of ketorolac as an analgesic for sea turtle rehabilitative medicine. Our objective was to determine the pharmacokinetics of a single 0.25 mg/kg intramuscular dose of ketorolac in a population of 16 captive-raised juvenile loggerhead sea turtles (Caretta caretta). A sparse sampling protocol was utilized, and blood samples were collected for 12 hours after administration of ketorolac. Samples were analyzed with high-pressure liquid chromatography (HPLC), and a nonlinear mixed effects model (NLME) was used to determine parameters for the population. With these methods, we identified a long elimination half-life (βT_1/2  = 11.867 hr) but a low maximum concentration (C_MAX  = 0.508 µg/mL) and concentrations were below the level proposed to be therapeutic in humans (EC₅₀  = 0.1-0.3 μg/mL) for most of the collection period. We conclude that ketorolac may not be an appropriate long-term analgesic for use in loggerhead sea turtles at this dose; however, it may have some benefit as a short-term analgesic.

The effect of surgery (Ovariohysterectomy) on the plasma disposition of meloxicam following intravenous administration in dogs

Background

Meloxicam (MLX) is a nonsteroidal anti-inflammatory drug used in the relief of postoperative pain for human and veterinary medicine. This study was designed to investigate the effect of surgery on the plasma disposition of MLX in dogs undergoing ovariohysterectomy following a single intravenous injection at a dose of 0.2 mg/kg bodyweight. Eight crossbred bitches were used in the study. A two-phase experimental design with a 10-day washout period was used. Pre-operative MLX was administered intravenously to 8 bitches about 10 days before surgery (Phase I, control) at a dose of 0.2 mg/kg bodyweight and peri-operative MLX was administered intravenously after anaesthesia and 15 min before the start of surgery (Phase II). Blood samples were collected from all animals at various times between 1 and 96 h after the drug administrations in both phases. The drug concentrations were analysed using high performance liquid chromatography.

Results

The volume of plasma MLX distribution at steady-state (Vd_ss) of the control group (Vd_ss: 263.0 ml/kg) was significantly greater (P < 0.05) compared to that of the surgery group (Vd_ss: 149.3 ml/kg). The AUC values were higher (29.5 vs. 23.0 μg.h²/ml) and the CL values were lower (7.7 vs. 10.5 ml.h/kg) in the surgery group compared to the control group, respectively, but differences were not significant.

Conclusions

The results of the present study indicated that surgery could alter the plasma disposition of MLX and thus the drug efficacy and side effects such as gastrointestinal ulceration, unusual bleeding and loss of kidney function/failure when repeated doses are used.