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  • Author or Editor: Alexander Livingston x
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in Journal of the American Veterinary Medical Association


Objective—To determine whether administration of ketoprofen would have analgesic effects in spontaneously breathing ducks anesthetized with isoflurane.

Animals—13 healthy adult wild-strain Mallard ducks.

Procedure—Each duck was anesthetized twice in a crossover study design with 6 days between randomized treatments. Ducks were given ketoprofen (5 mg/kg, IM) or saline (0.9% NaCl) solution after a constant plane of anesthesia was established. Analgesia was assessed by measuring heart and respiratory rates and duration of application of a noxious stimulus. The noxious stimulus was applied 30, 50, and 70 minutes after drug administration and was maintained until gross purposeful movements were seen or for a maximum of 5 seconds.

Results—At all 3 evaluation times, heart rate increases in response to the noxious stimulus were greater when ducks were given saline solution than when they were given ketoprofen. The increase in respiratory rate in response to the noxious stimulus was greater when ducks were given saline solution than when they were given ketoprofen only 70 minutes after drug administration. When ducks were given ketoprofen, duration of the noxious stimulus was significantly longer 50 and 70 minutes, but not 30 minutes, after drug administration.

Conclusion and Clinical Relevance—Ketoprofen reduced the increases in heart and respiratory rates associated with application of a noxious stimulus in spontaneously breathing adult Mallard ducks anesthetized with isoflurane delivered at approximately 2.9%, suggesting that ketoprofen had analgesic effects in these ducks. The onset of analgesic effects may be longer than 30 minutes in some ducks. (Am J Vet Res 2002;63:821–826)

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in American Journal of Veterinary Research


Objective—To evaluate the pharmacokinetics and thermal and mechanical antinociceptive effects of a fentanyl constant rate infusion (CRI) in conscious cats.

Animals—8 healthy adult cats.

Procedures—At a ≥ 14-day interval, 7 cats received a loading dose (LD) of fentanyl (5 μg/kg, IV [administered at 0 hours]) followed by fentanyl infusion (5 μg/kg/h, IV) for 2 hours or similar administrations of equivalent volumes of 0.9% saline (NaCl) solution. One cat received only the fentanyl treatment. For both treatments, sedation and adverse events were evaluated and mechanical threshold (MT) and thermal threshold (TT) testing was performed prior to (baseline) and at predetermined times up to 26 hours after LD administration; plasma fentanyl concentrations were determined at similar times when the cats received fentanyl.

Results—Fentanyl induced mild sedation during the infusion. The only adverse effect associated with fentanyl LD administration was profuse salivation (1 cat). Saline solution administration did not significantly change MT or TT over time. For the duration of the CRI, MT and TT differed significantly between treatments, except for TT 1 hour after LD administration. For the fentanyl treatment, MT and TT were significantly higher than baseline at 0.25 to 0.75 hours and at 0.25 to 1 hour, respectively. During the fentanyl CRI, mean ± SD plasma fentanyl concentration decreased from 4.41 ± 1.86 ng/mL to 2.99 ± 1.28 ng/mL and was correlated with antinociception; plasma concentrations < 1.33 ± 0.30 ng/mL were not associated with antinociception.

Conclusions and Clinical Relevance—Fentanyl CRI (5 μg/kg/h) induced mechanical and thermal antinociception in cats.

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in American Journal of Veterinary Research