Cardiovascular effects of romifidine in dogs.
OBJECTIVE
To characterize the cardiovascular effects of romifidine at doses ranging from 5 to 100 microg/kg of body weight, IV.


METHODS
25 clinically normal male Beagles.


METHODS
Romifidine was administered IV at a dose of 5, 10, 25, 50, or 100 microg/kg (n = 5/group). Heart rate, arterial pressure, central venous pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, body temperature, cardiac output, and PCV were measured immediately prior to and at selected times after romifidine administration. Cardiac index, stroke index, rate-pressure product, systemic and pulmonary vascular resistance indices, and left and right ventricular stroke work indices were calculated. Degree of sedation was assessed by an observer who was blinded to the dose administered.


RESULTS
Romifidine induced a decrease in heart rate, pulmonary arterial pressure, rate-pressure product, cardiac index, and right ventricular stroke work index and an increase in central venous pressure, pulmonary capillary wedge pressure, and systemic vascular resistance index. In dogs given romifidine at a dose of 25, 50, or 100 microg/kg, an initial increase followed by a prolonged decrease in arterial pressure was observed. Arterial pressure immediately decreased in dogs given romifidine at a dose of 5 or 10 microg/kg.


CONCLUSIONS
Results suggest that IV administration of romifidine induces dose-dependent cardiovascular changes in dogs. However, the 2 lowest doses (5 and 10 microg/kg) induced less cardiovascular depression, and doses > or = 25 microg/kg induced similar cardiovascular changes, suggesting that there may be a ceiling on the cardiovascular effects of romifidine.
Pypendop
B H
BH
Department of Small Animal Clinical Sciences, School of Veterinary Medicine, University of Liege, Belgium.
Verstegen
J P
JP
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D011897:Random Allocation; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D000777:Anesthetics; D007093:Imidazoles; C076257:romifidine