Sedative, analgesic, and cardiovascular effects of levomedetomidine alone and in combination with dexmedetomidine in dogs.
OBJECTIVE
To determine whether a high dose of levomedetomidine had any pharmacologic activity or would antagonize the sedative and analgesic effects of dexmedetomidine in dogs.


METHODS
6 healthy Beagles.


METHODS
Each dog received the following treatments on separate days: a low dose of levomedetomidine (10 microg/kg), IV, as a bolus, followed by continuous infusion at a dose of 25 microg/kg/h; a high dose of levomedetomidine (80 microg/kg), IV, as a bolus, followed by continuous infusion at a dose of 200 microg/kg/h; and a dose of isotonic saline (0.9% NaCl) solution, IV, as a bolus, followed by continuous infusion (control). For all 3 treatments, the infusion was continued for 120 minutes. After 60 minutes, a single dose of dexmedetomidine (10 microg/kg) was administered IV. Sedation and analgesia were scored subjectively, and heart rate, blood pressure, respiratory rate, arterial blood gas partial pressures, and rectal temperatures were monitored.


RESULTS
Administration of levomedetomidine did not cause any behavioral changes. However, administration of the higher dose of levomedetomidine enhanced the bradycardia and reduced the sedative and analgesic effects associated with administration of dexmedetomidine.


CONCLUSIONS
Results suggest that administration of dexmedetomidine alone may have some cardiovascular benefits over administration of medetomidine, which contains both dexmedetomidine and levomedetomidine. Further studies are needed to confirm the clinical importance of the effects of levomedetomidine in dogs.
Kuusela
E
E
Department of Clinical Sciences, University of Helsinki, Finland.
Vainio
O
O
Kaistinen
A
A
Kobylin
S
S
Raekallio
M
M
D000316:Adrenergic alpha-Agonists / Q000097:blood / Q000494:pharmacology*; D000698:Analgesia / Q000662:veterinary; D018712:Analgesics, Non-Narcotic / Q000097:blood / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D020927:Dexmedetomidine / Q000037:antagonists & inhibitors / Q000097:blood / Q000494:pharmacology*; D004285:Dogs / Q000502:physiology*; D004347:Drug Interactions; D004837:Epinephrine / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006993:Hypnotics and Sedatives / Q000097:blood / Q000494:pharmacology; D008297:Male; D020926:Medetomidine / Q000097:blood / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D011897:Random Allocation
D000316:Adrenergic alpha-Agonists; D018712:Analgesics, Non-Narcotic; D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine; D020926:Medetomidine; D009638:Norepinephrine; D004837:Epinephrine