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Cardiovascular effects of detomidine, a new α 2 ‐adrenoceptor agonist, in the conscious pony
Author(s) -
SARAZAN R. D.,
STARKE W. A.,
KRAUSE G. F.,
GARNER H. E.
Publication year - 1989
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1989.tb00688.x
Subject(s) - detomidine , xylazine , heart rate , medicine , cardiology , blood pressure , anesthesia , inotrope , ketamine
The cardiovascular effects of detomidine and xylazine were compared in six chronically instrumented, conscious ponies. Ponies were instrumented with a micromanometer in the left ventricular chamber, a Doppler flow probe on a coronary artery and sonomicrometer crystals in the left ventricular free wall. Heart rate, ventricular systolic pressure, stroke work, d P /d t max , minute work and coronary blood flow were measured for 4 h following intravenous injection of detomidine at several doses or xylazine at 1.1 mg/kg. Both drugs caused a profound hypertensive response at 15 s post‐injection. The magnitude of the pressure change did not increase with detomidine doses greater than 20 μg/kg. There was a dose‐dependent effect on the duration of the hypertension. Bradycardia and A‐V blockade of similar magnitude followed the hypertension at all drug doses. Both drugs caused a negative inotropic effect on the heart at all doses. Minute work, a mechanical index of myocardial O 2 demand, and coronary flow decreased to a similar extent following all drug treatments. With the exception of a greater hypertensive response, detomidine at the dosages studied, produced cardiovascular effects that were very similar to those of the recommended dosage of xylazine.