Anesthesia in Rodents and Rabbits

Surgical and other procedures that cause pain or discomfort in animals must be performed under general anesthesia. General anesthesia is also useful as a method of restraint for procedures that if performed without anesthesia would cause excessive stress for the animal and/or expose the human handler to potential hazards. In addition, because surgical and other invasive procedures can be expected to cause pain or discomfort beyond the duration of general anesthesia pain relief must be provided postoperatively.

Investigators are responsible for the assessment and management of all types of pain in their research animals and must include a pain management plan in their research protocols. Please contact an ARP veterinarian if you have questions or need additional information than what is provided in this website.

Controlled Drugs

A number of drugs used for anesthesia, analgesia, and euthanasia are regulated by the DEA (Drug Enforcement Administration) because of the potential for abuse. Investigators using these drugs are responsible for complying with applicable regulations including storage in a substantial locked cabinet or safe and maintenance of written records accounting for quantities received and dispensed. Investigators who will be using controlled drugs must apply to the DEA for the appropriate license.

Inhalant Anesthesia

Inhalant anesthetics allow precise control of the depth and duration of anesthesia in research animals and can be used in almost any species.  A variety of inhalant anesthetics are available, but isoflurane is the most commonly used. Isoflurane produces rapid induction and recovery from anesthesia. The depth of anesthesia can be easily and quickly altered. Virtually no metabolism occurs in the body because isoflurane is almost completely eliminated in expired air. Liver microsomal enzymes are minimally affected which results in little interference with drug metabolism or toxicology studies.

The use of isoflurane requires an anesthetic machine fitted with a precision vaporizer to deliver controlled amounts of anesthetic and oxygen. Anesthetic can be delivered to the animal via an anesthetic chamber, facemask or endotracheal tube. Isoflurane anesthetic systems designed for rodents are available in the University Park campus animal facilities. The CBL animal facility is also equipped with a surgical suite with inhalant anesthetic equipment suitable for use in nonrodent species. Please contact the ARP for information on training and use of this equipment.

Injectable Anesthesia

Anesthetics administered by injection are commonly used in laboratory species. Scroll down for dosage tables for several drugs in a variety of species. The following links provide dilution instructions for common anesthetic and analgesic drugs used in research rodents:

 

Preparation and Use of Injectable Anesthetic Drugs

Injectable drugs are a convenient way to administer anesthesia to animals in biomedical research, however, incorrect use of these drugs can lead to adverse events such as over- or under-dosing and post operative infections. In addition, many factors influence how a particular anesthetic drug and dosage will affect an individual animal. Variables such as strain, sex, age, and stress levels can result in significant variations in anesthetic depth and recovery times. Prior to using unfamiliar drugs, drug combinations or groups of animals for the first time, you may want to try a test administration on similar non-experimental animal(s). 

Most injectable anesthetic drugs are purchased as sterile, ready-to-use products from veterinary distributors. More than one drug may be combined to provide better anesthetic results (see below). The amount of drug administered to an animal is based on its body weight. Each animal needs to be weighed on the day of anesthesia. Young, growing animals and small species such as mice and rats, can change weight rapidly. A body weight recorded last week may not be accurate today. In addition, purchased drugs are typically supplied at a concentration that requires dilution with sterile water for ease of use in rodents. Sterile technique must be used in the preparation and administration of all injectable drugs. All needles, syringes and containers used to prepare, deliver or store drugs must be sterile. The use of non-sterile equipment can result in animal infections and/or illness. 

Injectable Anesthesia for Laboratory Animals

Drug(s)

Mouse

Rat

Rabbit

Hamster

Ketamine (K):    Xylazine (X)

80-120 mg/kg (K):10-16 mg/kg (X) IP (20-40 min. of anesthesia)

80-100 mg/kg (K): 5-10mg/kg (X) IP (20-50 min. of anesthesia)

22-50 mg/kg (K):2.5-10 mg/kg (X) IM (25-40 minutes of anesthesia)

50-200 mg/kg (K) + 5-10 mg/kg (X) IP 

Ketamine(K):  Dexmedetomidine (D)

75 mg/kg (K): 0.5 mg/kg (D) IP

75 mg/kg (K): 0.5 mg/kg (D) IP

 

100 mg/kg (K) + 0.125 mg/kg (D) IP

Ketamine (K): Xylazine (X): Acepromazine (A)

 

50 mg/kg (K): 5 mg/kg (X): 1 mg/kg (A) IP (30-45 minutes of anesthesia)

35 mg/kg (K): 5 mg/kg (X): 0.75 mg/kg (A) IM (45-75 min. of anesthesia)

 

Ketamine (K): Diazepam (D) - short duration; not surgical anesthesia

 

 

5 mg/kg (K): 0.25 mg/kg (D) IV. Mix equal volumes of ketamine (100 mg/ml) and diazepam ( 5 mg/ml). Dosage rate: 1 ml per 20 lbs body weight.

70 mg/kg (K) + 2 mg/kg (D) IP (Immobilization; not surgical anesthesia)

Inactin (thiobutabarbital, EMTU)

 

80-100 mg/kg IP (60-240 min. of anesthesia)

 

 

Pentobarbital -variable anesthetic depth; poor analgesia

30-50 mg/kg IP (20-40 min. of anesthesia)

40-50 mg/kg IP (20-60 min. of anesthesia)

 

Not recommended for hamsters due to high mortality

Tribromoethanol (Avertin)

240 mg/kg IP (15-45 min. of anesthesia)

 

 

 

Atipamezole (for reversal of dexmedetomidine & xylazine)

1.0 mg/kg IP or SQ

1.0 mg/kg IP or SQ

0.1-1.0 mg/kg IM, IP, SQ or IV (dose required depends on dose of xylazine administered)

0.1-1 mg/kg SQ or IP

Glycopyrrolate (preanesthetic)

 

 

0.1 mg/kg IM, SQ (decreases respiratory secretions, prevents bradycardia)

 

For information on other anesthetic drugs and dosages please consult an ARP veterinarian.

 


 

The information and drug dosages presented in this website are intended as a resource for Pennsylvania State University research investigators. No guarantee of drug efficacy or safety is made nor must information obtained from this site be substituted for professional veterinary advice.