In order to ensure appropriate use of Tribromoethanol (Avertin), the University of Connecticut's Institutional Animal Care and Use Committee has implemented a policy on the use of this drug. The Institutional Animal Care and Use Committee encourages the use of ketamine/xylazine and isoflurane rather than Tribromoethanol.

Background

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 amputation for Southern Blot analysis. Avertin is not a pharmaceutical grade drug. 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 Institutional Animal Care and Use Committee in the research proposal.

Action

Preparation

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 distilled water, stirring continuously, up to a final volume of 200 ml.
• Filter sterilizing through a 0.5 micron filter.
• Aliquot the final solution into 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

Storage

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

Use

Tribromoethanol may be approved for use after scientific and/or medical justification has been provided in the animal care and use protocol and after the Institutional Animal Care and Use Committee 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.

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References

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

Zeller, WM et al. Adverse Effects of Tribromoethanol as Used in the Production of Transgenic Mice. Laboratory Animal Science, 1998. October, 32(4): 407-413.

Kohn, DF et al. Anesthesia and Analgesia in Laboratory Animals, 1997.

Lieggi et al. An evaluation of preparation methods and storage conditions of tribromoethanol. Contemp. Top. Lab. Anim. Sci. 44(1):11-16. 2005.

A review of tribromoethanol anesthesia for production of genetically engineered mice and rats. Lab Anim. (NY). 34(10):47-52. 2005.