Effect of xylazine and detomidine on urine production in horses deprived of food and water.

This research focuses on the study of the effects of two drugs—fentanyl and buprenorphine—on cats, with fentanyl’s antinociceptive activity and buprenorphine’s systemic uptake after buccal administration being under scrutiny.

Fentanyl Study

• The study aimed to evaluate the onset and duration of fentanyl’s antinociceptive effect in cats, using a ramped thermal stimulus. It involved six young adult cats, with a mean weight of approximately 4.7 kg.
• Each feline was prepared a day before the study by having a cephalic catheter placed and its thorax hair clipped. A probe was attached to a band around the shaved area, which served as the thermal stimulus.
• The cats were administered fentanyl intravenously and were observed for signs of reaction to the stimulus, such as distinct skin twitch, jump, or turning to look at the probe. Observations were made at 5-minute intervals post-treatment for a duration of 3 hours.
• The results demonstrated that fentanyl causes pupil dilation and mild euphoria in cats with a rapid onset. The antinociceptive effect was significant for 110 minutes post-injection.

Buprenorphine Study

• The aim of this part of the research was to compare the pharmacokinetics of buprenorphine after buccal administration with that of intravenous and intramuscular injection, previously conducted on the same group of cats.
• 24 hours before each experiment, jugular catheters were inserted under a general anesthetic on six adult female cats, which weighed between 2.9 to 4.5 kg.
• The cats were then administered buprenorphine through their mouths, and blood samples were taken at intervals within 24 hours for pharmacokinetic profiling.
• The results showed that buccal administration was well received with a high percentage of bioavailability. Clearance was slower and volume of distribution smaller after buccal administration compared to other methods. It was thus inferred that buccal absorption of buprenorphine in cats is greater than in humans.

The research thus demonstrates the effects of the drugs fentanyl and buprenorphine on cats when administered through different routes.