Effects of a Single Opioid Dose on Gastrointestinal Motility in Rabbits (Oryctolagus cuniculus): Comparisons among Morphine, Butorphanol, and Tramadol

Abstract

The aim of this study was to evaluate and compare the effects of single doses of butorphanol, morphine, and tramadol on gastrointestinal motility in rabbits (Oryctolagus cuniculus) using non-invasive imaging methods, such as radiographic barium follow through and ultrasonographic contraction counts. Time-lapse radiographic and ultrasound examinations were performed before and after a single intramuscular dose of 5 mg kg−1 butorphanol, 10 mg kg−1 morphine, or 10 mg kg−1 tramadol. Pyloric and duodenal contraction counts by ultrasonography and radiographic repletion scores for the stomach and caecum were analysed using a mixed linear model. No significant effect was noted on ultrasound examinations of pyloric and duodenal contractions after administration of an opioid treatment. Morphine had a significant effect on the stomach and the caecum repletion scores, whereas butorphanol had a significant effect only on the caecum repletion score. Tramadol had no significant effect on the stomach or caecum repletion scores. The present findings suggest that a single dose of 5 mg kg−1 butorphanol or 10 mg kg−1 morphine temporarily slows gastrointestinal transit in healthy rabbits, preventing physiological progression of the alimentary bolus without the induction of ileus. In contrast, a single dose of 10 mg kg−1 tramadol has no such effects.

Comparison between Carprofen and Meloxicam for Post-Neutering Pain Management in Pet Rabbits

“…This molecule is commonly deemed safe when applied in rabbit anesthesia, with few adverse effects [ 13 , 20 ]. One study reported a temporary reduction in gastric motility following the administration of 10 mg kg −1 of butorphanol intramuscularly [ 37 ]. However, this dose is 20 times higher than that used in this study (0.2 mg kg −1 ); hence, the results may not be directly comparable to those of the cited study.…”

Lateral ear canal resection and bulla osteotomy with marsupialization to treat otitis media in rabbits: forty‐eight procedures

“…Morphine temporarily slows gastrointestinal transit in rabbits, but whether buprenorphine does is controversial. [33][34][35] Fluid therapy and syringe feeding are essential while the rabbit recovers until it eats and drinks adequately on its own. 36 Limitations of this study include the retrospective nature of data analysis, short follow-up length, and not performing CT scans later (3 or 6 months) to assess otitis media.…”

“…It is critical to provide ongoing analgesia for several days, while reducing narcotic requirements in postoperative care. Morphine temporarily slows gastrointestinal transit in rabbits, but whether buprenorphine does is controversial 33–35 . Fluid therapy and syringe feeding are essential while the rabbit recovers until it eats and drinks adequately on its own 36 …”