Which combination is a commonly used injectable anesthesia for mice?

• A. Isoflurane
• B. Ketamine/xylazine
• C. Ether
• D. Propofol

Answer: (B)

Combining ketamine with xylazine is a well-established injectable anesthesia in mice because the two drugs complement each other to produce reliable anesthesia with analgesia and smooth muscle relaxation. Ketamine acts as a dissociative anesthetic, providing analgesia and a loss of response to painful stimuli, while xylazine adds sedation, muscle relaxation, and extra analgesia through alpha-2 adrenergic effects. Together they create a dependable surgical plane when given by intraperitoneal injection, with rapid onset and a manageable duration for many procedures. This practical balance of efficacy, cost, and ease of use makes it a go-to injectable option in many labs.

Inhalant options like isoflurane are not injectable, and ether is outdated and unsafe. Propofol can be used in some settings, but it is less common for routine mouse anesthesia due to the need for careful dose titration and monitoring, and its higher risk of apnea.