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  • Author or Editor: Richard V. Shawley x
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SUMMARY

To investigate the effect of chloramphenicol, a cytochrome P-450 inhibitor, on the pharmacokinetics of propofol, either chloramphenicol (50 mg/kg of body weight, iv) or saline solution was administered iv to 5 Greyhounds in randomized manner, with at least 2 weeks between trials. Thirty minutes after either chloramphenicol or saline treatment, a bolus dose of propofol (10 mg/kg, iv) was administered, followed by a 2-hour infusion of propofol (0.4 mg/kg/min, iv). Samples for determination of blood propofol concentration were collected sequentially over a 6-hour period during each trial. After termination of propofol infusion, the time to spontaneous head lift, extubation, sternal recumbency, and standing was recorded. Blood propofol concentration was determined by use of high-performance liquid chromatography. Concentration-time data were fitted to a two-compartment open pharmacokinetic model and pharmacokinetic variables were determined, using a microcomputer program for modeling and simulation of concentration-time data. The effect of chloramphenicol on the pharmacokinetics of propofol and recovery time were evaluated, using paired t-tests and Wilcoxon's test for parameters that are not normally distributed (t½(β), Vd(ss), ClB). Significant (P < 0.05) effects of chloramphenicol pretreatment included increased t1/2(β) (by 209%), and decreased ClB (by 45%), and prolonged recovery indices (by 768 to 946%). These results indicate that cytochrome P-450 metabolic pathways have an important role in propofol clearance and propofol anesthetic recovery in Greyhounds.

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To determine whether epidural administration of detomidine hydrochloride to cattle induced analgesia of the perineum and to compare analgesic and systemic effects of epidural versus IM administration of detomidine at a dose of 40 μg/kg in cattle.

Animals

18 healthy adult cows.

Procedure

6 cows were given detomidine by epidural administration, 6 were given detomidine IM, and 6 (control group) were not given detomidine. Analgesia was assessed by determining responses to needle pinpricks in the perineum and flank and by applying electrical stimuli to the perineum and flank and determining the voltage that induced an avoidance response. Degree of sedation and ataxia were scored, and mean arterial pressure, heart rate, respiratory rate, and frequency of ruminal contractions were measured.

Results

Epidural and IM administration of detomidine induced comparable degrees of analgesia of the perineum and flank, accompanied by moderate sedation and ataxia, hypertension, cardiorespiratory depression, and rumen hypomotility.

Conclusions and Clinical Relevance

Epidural and IM administration of detomidine at a dose of 40 µg/kg induced similar analgesic and systemic effects in cattle. Epidural administration of detomidine did not appear to be advantageous over IM administration. (Am J Vet Res 1999;60:1242–1247)

Free access
in American Journal of Veterinary Research