A single injection of high-concentration buprenorphine significantly reduces food and water intake as well as fecal and urine production in New Zealand White rabbits (Oryctolagus cuniculus).

Objective: To evaluate selected gastrointestinal side effects of high-concentration buprenorphine (HCB) in healthy rabbits.

Animals: 10 healthy New Zealand White rabbits ranging in body weight between 3.0 and 3.8 kg.

Methods: Eight, 6-month-old, New Zealand White rabbits received a single injection of HCB SC (0.24 mg/kg). The rabbits were previously randomized to receive SC and oral saline as a control. Two rabbits received saline for the purpose of blinding the outcome assessors. Food and water consumption, fecal and urine production, and fecal pellet number were recorded for all rabbits before HCB administration and the 3 days postinjection.

Results: A clinically and statistically significant decrease in food and water consumption was observed in rabbits receiving an injection of HCB, compared to rabbits receiving saline. In the 24 hours after injection, HCB-treated rabbits consumed a median of 17 g of food (range, 0 to 82 g), while saline-treated rabbits consumed 122 g of food (31 to 181 g). Rabbits receiving HCB injections also produced significantly less feces both in terms of pellet numbers and overall quantity, along with decreased urine production.

Clinical Relevance: A single administration of HCB has a clinically significant impact on multiple physiological functions in healthy rabbits. Administration of this drug could potentially worsen clinical signs of anorexia and decrease defecation in healthy rabbits. The effects of HCB on diseased or painful rabbits are not yet known.