Guidelines for Anesthesia and Analgesia of Laboratory Animals (Material adapted from the University of Iowa Animal Care Unit and Stanford University)

Anesthesia and Analgesia of Mice:
Anesthesia and Analgesia of Rats:
Anesthesia and Analgesia of Rabbits:
Anesthesia and Analgesia of Guinea Pigs:
Anesthesia and Analgesia of Fish and Amphibians:

Alternatives to the use of Methoxyflurane in Rodents:

 

Anesthesia and Analgesia of Mice

Parenteral Anesthesia:

Anticholinergics

  • Atropine, 0.04 mg/kg; IM,SQ; (1)

Tranquilizers 

  • Diazepam, 5 mg/kg; IP; (2)

Neuroleptanalgesics

  • Droperidol and fentanyl; (0.002 or 0.005 ml/gm of a 10% solution); IM;(1)

Dissociative Anesthetics

  • Ketamine, 100-200 mg/kg; IM; IP;(7) 
  • Ketamine, 80 mg/kg; IP + Xylazine, 10-16 mg/kg; IP;(3) 
  • Ketamine, 100 mg/kg + Acepromazine, 2.5 mg/kg; IM;(12) 
  • Ketamine, 22-44 mg/kg + Xylazine, 2.5 mg/kg + Acepromazine, 0.75 mg/kg; IM;(1) 

Barbiturates 

  • Pentobarbital, 5 mg/kg (newborn animals); IP;(1) 
  • Pentobarbital, 35-70 mg/kg; IV;(1)
  • Pentobarbital, 40-90 mg/kg; IP;(1)
  • Thiopental or Thiamylal, 25-50 mg/kg; IV;(1)(7)

Examples:

Agent Dose Duration of surgical anesthesia
Pentobarbital 50 mg/kg IP 20-40 minutes
Ketamine, xylazine 80-100 mg/kg + 10 mg/kg IP29 20-30 minutes

Analgesics: 

  • Acetaminophen, 300 mg/kg, q 4 hr.; PO;(4) 
  • Meperidine, 20-40 mg/kg; IP;(1)
  • Meperidine, 10-20 mg/kg, q 2-3 hr.; SQ, IM;(4) 
  • Ketoprofen, 2-5 mg/kg, q 8-12 hour; SQ,IM;
  • Buprenorphine, 0.05-0.1 mg/kg, q 6-12 hr.; SQ;(4) 
  • Butorphanol, 1-5 mg/kg, q 4 -8hr, SQ;(4) 
  • Codeine, 60-90 mg/kg, q 4 hr.; PO;(4) 
  • Codeine, 20 mg/kg; SQ;(4) 
  • Morphine, 2-5 mg/kg, q hourly; SQ;(4) 
  • Morphine, 5-10 mg/kg; IP;(1)

Anesthesia and Analgesia of Rats:

Parenteral Anesthesia:

Anticholinergics

  • Atropine, 0.05 mg/kg; SQ (12)
  • Glycopyrrolate, 0.5 mg/kg; IM; (16) 

Tranquilizers 

  • Acepromazine, 1 mg/kg; IM; (12)
  • Diazepam, 2-4 mg/kg; IM; (2)
  • Chlorpromazine, 1-2 mg/kg; IM; (1)

Neuroleptanalgesics

  • Droperidol and fentanyl, 0.13 ml/kg (sedation); IM; (11) 
  • Droperidol and fentanyl, 0.33 ml/kg; IM, IP; (surgical plane); (9) 

Dissociatives

  • Ketamine, 50 mg/kg; IM; (sedative) (3) 
  • Ketamine, 75-90 mg/kg; IV; ( anesthetic) (13)
  • Ketamine, 22-44 mg/kg + Xylazine 2.5-10mg/kg + Acepromazine 0.75mg/kg; IM; (1) 
  • Ketamine, 75 mg/kg + Acepromazine, 25 mg/kg: IM; (12) 

Barbiturates

  • Pentobarbital, 35-45 mg/kg (use diluted solution); IP; (1) 
  • Thiopental/Thiamylal, 20 mg/kg; IV; (1)

Examples:

Agent Dose Onset Duration
Pentobarbital 30 mg/kg IP 19 5 90 minutes
Pentobarbital 40 mg/kg IP 19 5 120 minutes
Ketamine, xylazine 40 mg/kg; 5 mg/kg IP19 5 80 minutes
Ketamine, xylazine 60 mg/kg; 7.5 mg/kg19 2 115 minutes
Ketamine, medetomidine 75 mg/kg; 0.5 mg/kg29   20-30 minutes

Analgesics:

  • Ketoprofen, 2-5 mg/kg, q 8-12 hour; SQ,IM;
  • Buprenorphine, 0.01-0.05 mg/kg, q 6-12 hr.; SQ, IV; (4) 
  • Buprenorphine, 0.1-0.25 mg/kg, q 6-12 hr.; PO; (29) 
  • Butorphanol, 1.0-2.0 mg/kg, q 4 hr; SQ; (14)
  • Codeine, 60-90 mg/kg, q 4hr; SQ; (4)  
  • Meperdine, 10-20 mg/kg, q 2-3 hr.; SQ, IM; (4) 
  • Morphine, 2-5 mg/kg, q hr.; SQ; (4) 

Anesthesia and Analgesia of Rabbits:

Parenteral Anesthesia:

Anticholinergics

  • Atropine, 0.05-0.5 mg/kg; SQ (1). Approximately 60% of all rabbits have an atropinesterase that can inactivate atropine.
  • Glycopyrrolate, 0.1 mg/kg; IM; (16) 

Tranquilizers 

  • Acepromazine, 1-10 mg/kg; IM; (1)
  • Diazepam, 5-10 mg/kg; IM; (2)
  • Xylazine, 3-9 mg/kg; IV; (1)
  • Xylazine, 5 mg/kg; IM; (7)

Neuroleptanalgesics

  • Droperidol and fentanyl, 0.125ml/kg (sedation); IM; (2) 
  • Droperidol and fentanyl, 0.062 ml/kg; SQ; (sedation); (14) 
  • Droperidol and fentanyl, 0.22 ml/kg (anesthesia); IM; (9) 

Dissociatives

  • Ketamine, 44 mg/kg; IM; (1)(7) 
  • Ketamine, 15-20 mg/kg; IV; (7)
  • Ketamine, 35 mg/kg + Xylazine 5 mg/kg; IM; (1) 
  • Ketamine, 30 mg/kg + Diazepam, 5 mg/kg (sedation, poor analgesia); IM; (3) 

Barbiturates

  • Methohexital, 4-10 mg/kg (use diluted solution); IV; (2) 
  • Pentobarbital, 25-40 mg/kg (use diluted solution); IV; (7) 
  • Thiamylal, 31 mg/kg (mean dose; use 1% solution); IV; (9)
  • Thiopental, 30 mg/kg; IV; (12)

Examples:

Agent Dose (mg/kg) Duration
Ketamine,
xylazine13 		35 mg/kg IM,
5 mg/kg IM 		25-4029 minutes
Ketamine,
xylazine29		 10 mg/kg IV,
3 mg/kg IV		 20-30 minutes
Ketamine,
xylazine,
acepromazine13 		35 mg/kg IM,
5 mg/kg IM,
0.75 mg/kg IM 		100 minutes
Ketamine,
xylazine,
butorphanol29		 35 mg/kg IM,
5 mg/kg IM,
0.1 mg/kg IM		 60-90 minutes
Pentobarbital:14 Induce with 10 mg/ml IV and administer increments of 2-10 mg until a satisfactory level of anesthesia is reached 20-30 minutes

Inhalation Anesthesia:

Several gaseous anesthetics such as halothane or isoflurane have been used successfully in the rabbit. These anesthetics require the use of a precision vaporizer to deliver the appropriate amount of anesthetic and appropriate scavenging systems to prevent personnel exposure to the anesthetic. Since induction will require "masking the rabbit" or placement of an endotracheal tube it is standard practice to use a preanesthetic.

Analgesics

  • Buprenorphine, 0.01-0.05 mg/kg, q 6-12 hr.; SQ, IV; (4) 
  • Butorphanol, 0.1-0.5 mg/kg, q 4 hr.; IV (4) 0.5-1.0 mg/kg, q 2-3 hr;SQ,IM; (14) 
  • Meperdine, 10 mg/kg, q 2-3 hr.; SQ, IM; (4) 
  • Morphine, 2-5 mg/kg, q 2-4 hr.; SQ, IM; (4) 
  • Nalbuphine, 1-2 mg/kg, q 4-5 hr.; IV; (4) 
  • Pentazocine, 5 mg/kg, q 2-4 hr.; IV; (4) 

 

Anesthesia and Analgesia of Guinea pigs:

Parenteral Anesthesia:

Examples:

Agent Dose (mg/kg) Duration
Ketamine-xylazine*1 30; 5 IM 30-45 minutes
Ketamine-xylazine 3 44; 5 IM 74 minutes
Pentobarbital
fentanyl-droperdiol!1		 15 mg/kg IP +
0.4ml/kg IM 		60 minutes
Pentobarbital29 37 mg/kg IP 60-90 minutes

* Note: Not suitable for procedures requiring deep anesthesia.

Note: High doses of fentanyl-droperdiol (0.88 ml/kg has been associated with muscle and nerve damage)

Inhalation Anesthesia:

Several gaseous anesthetics such as methoxyflurane or isoflurane have been used successfully in the guinea pig. Isoflurane requires the use of a precision vaporizer to deliver the appropriate amount of anesthetic and both require appropriate scavenging systems to prevent personnel exposure to the anesthetic. Induction will require "masking the guinea pig" or the use of an induction chamber. An endotracheal tube should be utilized to maintain anesthesia. Halothane in guinea pigs has been associated with hepatotoxicity 8.

Analgesia:

Agent Dose (mg/kg)
Morphine sulphate12 2-5 mg/kg SC every 4 hours
Buprenorphine 4 0.05 mg/kg SQ TID to BID
Indomethacin12 2.5-8.8 mg/kg PO

 

Anesthesia and Analgesia of Fish and Amphibians

Immersion Anesthetics

  • Tricaine methane sulfonate (MS222), 300-500 mg/L (larva); 500-2000 mg/L (adults) (buffer with 10-25 m Eq/L sodium bicarbonate) ( 17, 19 )
  • Benzocaine, 10-50 mg/L (larva); 300 mg/L (adults) ( 17, 19 )

Injectable Anesthetics

  • Tricaine methane sulfonate, 100 mg/kg; SQ; IP; SQ ( 17, 19 )
  • Tricaine methane sulfonate, 50-150 mg/kg; SQ; IM ( 19 )
  • Ketamine, 50-150 mg/kg; IM ( 17 )

 

Alternatives to Methoxyflurane

There are four alternatives to methoxyflurane.

1.    Several parenteral anesthetics are available for use.   However, they all have prolonged recovery times when compared to gaseous anesthetics. 

2.    Other gaseous anesthetics typically require the use of a precision vaporizer for use.   If you would like assistance in setting up your own anesthetic system ACU will provide assistance.  Note: you still have to insure that anesthetic gases are scavenged properly.

Halothane and Isoflurane can be utilized in an anesthetic chamber (drop jar) if the volume of the anesthetic is known and the volume of liquid anesthetic needed to produce the desired concentration is calculated.  The table provides the number of milliliters of liquid anesthetic needed to produce various anesthetic concentrations.   This technique would be only be appropriate for procedures that only require short term anesthesia since the animal will begin to recover once it is removed from the anesthetic chamber.

Internal volume of anesthetic chamber (ml)

Concentration of anesthetic 1000 ml 2000 ml 3000 ml 4000 ml 5000 ml
Halothane          
1% 0.04* 0.09 0.13 0.18 0.22
2% 0.09 0.18 0.26 0.35 0.44
3% 0.13 0.26 0.40 0.53 0.66
4% 0.18 0.35 0.53 0.71 0.88
5% 0.22 0.44 0.66 0.88 1.10
Isoflurane          
1% 0.05 0.10 0.15 0.20 0.26
2% 0.10 0.20 0.31 0.41 0.51
3% 0.15 0.31 0.46 0.61 0.77
4% 0.20 0.41 0.61 0.82 1.02
5% 0.26 0.51 0.77 1.02 1.28

* Volume given in milliliters
Calculations at 20C and 760mmHg
Anesthesia and Analgesia in Laboratory Animals. 1997. Academic Press p32.

3.    Halothane/Oil mixture:  To overcome the high concentration that occurs when halothane is utilized in a drop jar or in a nose cone dilute the halothane in light paraffin oil or USP grade mineral oil . Use the diluted halothane/oil mix in a nose cone or drop jar (chamber) at a  concentration of 10% and 5% (v/v) respectively  (10 ml of diluted mixture in a 4 L chamber). The vapor pressure of the halothane is diminished to less than 15% of its original value.  Diluted halothane is unstable and needs to be made fresh for each use. Also  to recharge the chamber it is better to remove the residual oil/halothane mixture and utilize a new cotton pledget soaked with the appropriate amount.  If you add additional mixture to the original pledget, residual oil in the pledget can further dilute the mixture to a point where it has no efficacy.  Isoflurane can not be utilized in this manner.

4.    We do not recommend the use of ether.  It is not allowed in the Vivarium and is an explosion hazard.  Ether cannot be used as an anesthetic.

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