Metomidate, etomidate and fentanyl as injectable anaesthetic agents in mice

Area of Science:

• Veterinary pharmacology
• Anesthesiology
• Rodent models

Background:

• Injectable anesthetics are crucial for rodent research.
• Evaluating novel anesthetic combinations is essential for improving preclinical study conditions.

Purpose of the Study:

• To compare the efficacy of metomidate and etomidate as injectable anesthetics in mice.
• To assess the effectiveness of a metomidate-fentanyl mixture for prolonged surgical anesthesia.

Main Methods:

• Mice were administered metomidate (50 mg/kg) or etomidate (30 mg/kg) via intraperitoneal injection for light anesthesia.
• A metomidate-fentanyl mixture (60 mg/kg: 0.06 mg/kg) was administered subcutaneously for full surgical anesthesia.
• Anesthetic durations and efficacy were compared between agents and administration routes.

Main Results:

• Metomidate and etomidate produced light surgical anesthesia lasting 12-15 minutes via intraperitoneal injection.
• Subcutaneous administration of the metomidate-fentanyl mixture resulted in approximately 160 minutes of full surgical anesthesia.
• The metomidate-fentanyl combination demonstrated superior anesthetic duration and efficacy compared to etomidate-fentanyl and other tested anesthetics.

Conclusions:

• Metomidate-fentanyl is a highly effective injectable anesthetic for mice, providing prolonged surgical anesthesia.
• The metomidate-fentanyl combination is superior to pentobarbitone and tribromoethanol for injectable anesthesia in mice.