Advertisement

Comparison of medetomidine and dexmedetomidine as premedicants in dogs undergoing propofol-isoflurane anesthesia

Erja KuuselaDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Erja Kuusela in
Current site
Google Scholar
PubMed
Close
 DVM
,
Marja RaekallioDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Marja Raekallio in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Misse VäisänenDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Misse Väisänen in
Current site
Google Scholar
PubMed
Close
 DVM
,
Katja MykkänenDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Katja Mykkänen in
Current site
Google Scholar
PubMed
Close
 DVM
,
Hannu RopponenDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Hannu Ropponen in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Outi VainioDepartment of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Search for other papers by Outi Vainio in
Current site
Google Scholar
PubMed
Close
 DVM, PhD

Abstract

Objective—To compare 3 dose levels of medetomidine and dexmedetomidine for use as premedicants in dogs undergoing propofol-isoflurane anesthesia.

Animals—6 healthy Beagles.

Procedure—Dogs received medetomidine or dexmedetomidine intravenously at the following dose levels: 0.4 µg of medetomidine or 0.2 µg of dexmedetomidine/kg of body weight (M0.4/D0.2), 4.0 µg of medetomidine or 2.0 µg of dexmedetomidine/ kg (M4/D2), and 40 µg of medetomidine or 20 µg of dexmedetomidine/kg (M40/D20). Sedation and analgesia were scored before induction. Anesthesia was induced with propofol and maintained with isoflurane. End-tidal isoflurane concentration, heart rate, and arterial blood pressures and gases were measured.

Results—Degrees of sedation and analgesia were significantly affected by dose level but not drug. Combined mean end-tidal isoflurane concentration for all dose levels was higher in dogs that received medetomidine, compared with dexmedetomidine. Recovery time was significantly prolonged in dogs treated at the M40/D20 dose level, compared with the other dose levels. After induction, blood pressure decreased below reference range and heart rate increased in dogs treated at the M0.4/D0.2 dose level, whereas blood pressure was preserved in dogs treated at the M40/D20 dose level. However, dogs in these latter groups developed profound bradycardia and mild metabolic acidosis during anesthesia. Treatment at the M4/D2 dose level resulted in more stable cardiovascular effects, compared with the other dose levels. In addition, PaCO2 was similar among dose levels.

Conclusions and Clinical Relevance—Dexmedetomidine is at least as safe and effective as medetomidine for use as a premedicant in dogs undergoing propofol-isoflurane anesthesia. (Am J Vet Res 2001;62:1073–1080)

Abstract

Objective—To compare 3 dose levels of medetomidine and dexmedetomidine for use as premedicants in dogs undergoing propofol-isoflurane anesthesia.

Animals—6 healthy Beagles.

Procedure—Dogs received medetomidine or dexmedetomidine intravenously at the following dose levels: 0.4 µg of medetomidine or 0.2 µg of dexmedetomidine/kg of body weight (M0.4/D0.2), 4.0 µg of medetomidine or 2.0 µg of dexmedetomidine/ kg (M4/D2), and 40 µg of medetomidine or 20 µg of dexmedetomidine/kg (M40/D20). Sedation and analgesia were scored before induction. Anesthesia was induced with propofol and maintained with isoflurane. End-tidal isoflurane concentration, heart rate, and arterial blood pressures and gases were measured.

Results—Degrees of sedation and analgesia were significantly affected by dose level but not drug. Combined mean end-tidal isoflurane concentration for all dose levels was higher in dogs that received medetomidine, compared with dexmedetomidine. Recovery time was significantly prolonged in dogs treated at the M40/D20 dose level, compared with the other dose levels. After induction, blood pressure decreased below reference range and heart rate increased in dogs treated at the M0.4/D0.2 dose level, whereas blood pressure was preserved in dogs treated at the M40/D20 dose level. However, dogs in these latter groups developed profound bradycardia and mild metabolic acidosis during anesthesia. Treatment at the M4/D2 dose level resulted in more stable cardiovascular effects, compared with the other dose levels. In addition, PaCO2 was similar among dose levels.

Conclusions and Clinical Relevance—Dexmedetomidine is at least as safe and effective as medetomidine for use as a premedicant in dogs undergoing propofol-isoflurane anesthesia. (Am J Vet Res 2001;62:1073–1080)