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Injectable Anesthesia

Anesthetics administered by injection are commonly used in laboratory species. Scroll down for dosage tables and dilution instructions for several drugs and combinations of drugs in a variety of species.

Preparation of Anesthetic Mixtures

While injectable drugs are a convenient way to administer anesthesia to rodents in biomedical research, incorrect use of these drugs can lead to adverse events such as over- or under-dosing and post operative infections. Here are some important guidelines that must be followed to insure animals are appropriately anesthetized and recover uneventfully.

The amount of drug administered to each animal is based on its body weight. Each animal needs to be weighed on the day of anesthesia. Mice and rats, especially young, growing animals, can change weight rapidly. A body weight recorded last week may not be accurate today.

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 variations in anesthetic depth and recovery times. Try a test administration on non-experimental animals prior to using unfamiliar drugs, drug combinations or groups of animals.

Sterile technique must be used in the preparation and administration of injectable drugs. All needles, syringes and containers used to deliver or store drugs must be sterile. The use of non-sterile equipment can result in animal infections and/or illness.

Controlled drugs are regulated by the U.S. Drug Enforcement Administration and must be stored under double lock and key. Appropriate use and disposal records must be maintained.

Injectable Anesthesia for Laboratory Animals

Drug(s)

Mouse

Rat

Rabbit

Ketamine:Xylazine

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)

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

Ketamine:Xylazine: Acepromazine

 

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:Valium - short duration, light anesthesia

 

 

5 mg/kg (K): 0.25 mg/kg (V) IV.

Mix equal volumes of ketamine (100 mg/ml) and valium ( 5 mg/ml). Dosage rate: 1 ml per 20 lbs body weight.

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)

 

Tribromoethanol (Avertin)

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

 

 

Atipamezole (for reversal of Xylazine)

1.0 mg/kg IP

1.0 mg/kg IP

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

Glycopyrrolate (preanesthetic)

 

 

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

For injectable anesthetic guidelines in other species please consult an ARP veterinarian.

Dilutions of Injectable Anesthetic Mixtures for Use in Rodents

Mouse

Ketamine/Xylazine

Dosage:
Ketamine 120 mg/kg
  Xylazine 16.0 mg/kg
     
Dose Rate:
0.1 ml/10 gm body weight IP*  
     
Volumes:
Ketamine 0.60 ml
  Xylazine at 20 mg/ml*** 0.40 ml
  WFI** 4.00 ml
  Total volume 5.0 ml = 50 doses

* IP = intraperitoneal injection ** WFI = water for injection

***Xylazine in this mixture is at a concentration of 20 mg/ml. Xylazine is available in concentrations of 20 mg/ml and 100 mg/ml.

Rat

Ketamine/Xylazine

Dosage:
Ketamine 100 mg/kg
  Xylazine 10 mg/kg
     
Dose Rate:
0.2 ml/100 gm body weight IP*  
     
Volumes:
Ketamine 2.0 ml
  Xylazine at 20 mg/ml 1.0 ml
  WFI** 1.0 ml
  Total volume 4.0 ml = 20 doses

* IP = intraperitoneal injection ** WFI = water for injection

Xylazine in the calculation above is at a concentration of 20mg/ml. Xylazine is also available at a concentration of 100 mg/ml. If using 100 mg/ml the volume of xylazine would be 0.2 ml with a volume of 1.8 ml of WFI. The volume of ketamine would remain the same.

Ketamine/Xylazine/Acepromazine

Dosage:
Ketamine 50 mg/kg
  Xylazine 5 mg/ml
  Acepromazine 1.0 mg/kg
     
Dose Rate:
0.2 ml/100 gm body weight IP*  
     
Volumes:
Ketamine 1.0 ml
  Xylazine at 20 mg/ml 0.5 ml
  Acepromazine 0.2 ml
  WFI** 2.3 ml
  Total volume 4.0 ml = 20 doses

* IP = intraperitoneal injection ** WFI = water for injection

Xylazine in the calculation above is at a concentration of 20mg/ml. Xylazine is also available at a concentration of 100 mg/ml. If using 100 mg/ml the volume of xylazine would be 0.1 ml with a volume of 2.7 ml of WFI. The volume of ketamine would remain the same.