Objective—To evaluate effects of injection with a nonsteroidal anti-inflammatory drug (NSAID) followed by oral administration of an NSAID on the gastrointestinal tract (GIT) of healthy dogs.
Animals—6 healthy Walker Hounds.
Procedures—In a randomized, crossover design, dogs were administered 4 treatments consisting of an SC injection of an NSAID or control solution (day 0), followed by oral administration of an NSAID or inert substance for 4 days (days 1 through 4). Treatment regimens included carprofen (4 mg/kg) followed by inert substance; saline (0.9% NaCl) solution followed by deracoxib (4 mg/kg); carprofen (4 mg/kg) followed by carprofen (4 mg/kg); and carprofen (4 mg/kg) followed by deracoxib (4 mg/kg). Hematologic, serum biochemical, and fecal evaluations were conducted weekly, and clinical scores were obtained daily. Endoscopy of the GIT was performed before and on days 1, 2, and 5 for each treatment. Lesions were scored by use of a 6-point scale.
Results—No significant differences existed for clinical data, clinicopathologic data, or lesion scores in the esophagus, cardia, or duodenum. For the gastric fundus, antrum, and lesser curvature, an effect of time was observed for all treatments, with lesions worsening from before to day 2 of treatments but improving by day 5.
Conclusions and Clinical Relevance—Sequential administration of NSAIDs in this experiment did not result in clinically important gastroduodenal ulcers. A larger study to investigate the effect of sequential administration of NSAIDs for longer durations and in dogs with signs of acute and chronic pain is essential to substantiate these findings.
Objective—To evaluate perioperative administration of gabapentin as an adjunct for analgesia in dogs undergoing amputation of a forelimb.
Design—Randomized, controlled trial.
Animals—30 client-owned dogs.
Procedures—On the day before surgery, a baseline pain evaluation was performed in each dog by use of multiple pain assessment methods. Dogs then received gabapentin (10 mg/kg [4.5 mg/lb], PO, once, followed by 5 mg/kg [2.3 mg/lb], PO, q 12 h for 3 additional days) or a placebo. On the day of surgery, dogs were anesthetized and forelimb amputation was performed. Fentanyl was infused after surgery for 18 to 24 hours; use of other analgesics was allowed. In-hospital pain evaluations were repeated at intervals for 18 hours after surgery, and owners were asked to evaluate daily their dog's activity, appetite, and wound soreness for the first 3 days after discharge from the hospital. Results were analyzed by use of a repeated-measures ANOVA.
Results—Pain evaluation scores did not differ significantly between gabapentin and placebo groups in the hospital or at home after discharge.
Conclusions and Clinical Relevance—As an adjunct to other analgesics and anesthetics, gabapentin, at the dose and frequency used in this study, did not provide a significant benefit for the management of acute perioperative pain in dogs undergoing forelimb amputation. The small sample size and number of other confounding factors, such as aggressive use of other analgesics, limited the likelihood of detecting a benefit of gabapentin. Other gabapentin doses or dosing regimens warrant further study.
Objective—To assess the pharmacokinetics and pharmacodynamics of morphine in llamas.
Animals—6 healthy adult llamas.
Procedures—Llamas received morphine sulfate in a randomized crossover design. In phase 1, they received IV or IM administration of morphine at 0.05 or 0.5 mg/kg, respectively; in phase 2, they received IV administration of morphine at 0.05, 0.25, or 0.5 mg/kg. Plasma morphine and morphine-6-glucuronide concentrations were determined by validated methods. Body temperature, heart rate, respiratory rate, sedation, and analgesia were assessed and compared with plasma concentrations by regression analysis.
Results—Total body clearance was similar between IV administration of morphine sulfate at 0.25 and 0.5 mg/kg (mean ± SD, 25.3 ± 6.9 mL/min/kg and 27.3 ± 5.9 mL/min/kg, respectively), and linearity was demonstrated between these doses. Bioavailability of morphine following IM administration at 0.5 mg/kg was 120 ± 30%. Body temperature and sedation increased as the dose of morphine administered increased. Heart rate was unaffected by varying doses. Respiratory rate decreased as dose increased. Analgesia was difficult to assess as a result of high individual variability. Intravenous administration of morphine at 0.25 mg/kg provided the most consistent increase in tolerance to electric stimulation. Pharmacodynamic modeling revealed a sigmoidal relationship between plasma concentration and sedation score.
Conclusions and Clinical Relevance—Morphine was characterized by a large apparent volume of distribution and high systemic clearance in llamas. A prolonged half-life was observed with IM injection. Intravenous administration of morphine sulfate at 0.25 mg/kg every 4 hours is suggested for further study.