Use of Avertin


In order to ensure appropriate use of Tribromoethanol (Avertin), UConn Health’s Institutional Animal Care and Use Committee (IACUC) has implemented a policy on the use of this drug. The IACUC encourages the use of pharmaceutical grade compounds such as ketamine/xylazine and isoflurane rather than Tribromoethanol.


Tribromoethanol (Avertin) is an anesthetic that provides rapid induction and recovery for single use, short duration (approximately 15-20 minutes) surgical procedures in rodents. Tribromoethanol has been commonly used in the production of transgenic animals to facilitate procedures such as embryo transfer, vasectomy, or distal tail snip for DNA analysis. Tribromoethanol is not commercially available and investigators who wish to use it as an anesthetic must make their own solutions. Improper preparation, storage, or use of Tribromoethanol can result in high mortality losses. In particular, Tribromoethanol degrades in the presence of heat and light, producing toxic by-products that are potent gastrointestinal irritants. Adverse effects are common in mice following any second exposure to Tribromoethanol regardless of the dosing interval; therefore, this anesthetic is approved for one administration only as a survival anesthetic in mice.

Any proposed deviation from these guidelines must be fully explained and justified to the IACUC in the research proposal.



Tribromoethanol must be prepared as follows:

  • Dissolve 2.5 grams of 2,2,2-tribromoethanol in 5 ml of tert-amyl alcohol.  This requires heating to approximately 40°C and stirring vigorously.
  • Add sterile PBS, stirring continuously, up to a final volume of 200 ml
  • Filter sterilize through a 0.5 micron filter
  • Aliquot the final solution into sterile light protected containers.  Containers must be labeled:
    • Tribromoethanol
    • 12.5 mg solution
    • Date of preparation
    • Date of expiration (two weeks from reconstitution)
    • Initials of person who prepared the solution


Tribromoethanol must be stored at 2-8°C in light protected containers.


Tribromoethanol may be approved for use after scientific and/or medical justification has been provided has been provided in the animal care and use protocol and after IACUC review for a single, survival administration to adult mice. If a second administration of tribromoethanol is given, the animals must be euthanized prior to awakening from the anesthetic. The anesthetic should be administered at a dose of 250 mg/kg given IP.

Dispose of any solution that is past the two-week expiration date, has crystals, or has changed from a clear solution to a yellow solution.


1. Papaioannou, VE and Gox, JG. Efficacy of Tribromoethanol Anesthesia in Mice. Laboratory Animal Science, 1993. April, 43(2): 189-192.

2. Zeller, WM; Burki, G; and Panoussis, B. Adverse Effects of Tribromoethanol as Used in the Production of Transgenic Mice. Laboratory Animal Science, 1998. October, 32(4): 407-413.

3. Kohn, DF; Wixson, SK; White, WJ; and Benson, GJ. Anesthesia and Analgesia in Laboratory Animals, 1997.

4. Efficacy and Safety of Stored and Newly Prepared Tribromoethanol in ICR Mice. Contem Top Lab Animal Sci, 2005. 44(1): 17-22.

5. An Evaluation of Preparation Methods and Storage Conditions of Tribromoethanol. Contem Top Lab Animal Sci, 2005. 44(1): 11-16.

Effective Dates:  June 17, 2021 through June 30, 2024