UT Southwestern IACUC Policy IACUC # 101
Approval Date:__3/1/06____ Page 1 of 1
Policy on the Use of Tribromoethanol (Avertin)
Rationale:
Tribromoethanol is appropriate for short term procedures in mice, especially surgical procedures. It is best used in situations where it will be given only on a single occasion. However, adverse reports about the efficacy and safety of Tribromoethanol, (TBE) combined with the availability of effective pharmaceutical grade alternatives, have made the continued routine use of TBE for rodent anesthesia controversial.
Advantages:
• Tribromoethanol induces anesthesia rapidly and provides good surgical analgesia for approximately one hour. Since it is given by injection, one is spared of the occupational health risks and technical difficulties associated with volatile anesthetics. If used appropriately, TBE has a good margin of safety.
Disadvantages:
• TBE is an irritant, especially at high doses, high concentrations, or with repeated use. Adhesions are sometimes seen in the abdominal cavity after IP injections.
• TBE degrades in the presence of heat or light to produce toxic byproducts. Degraded solutions can be both nephrotoxic and hepatotoxic. Administration of degraded TBE solutions has been associated with death, often 24 hours after surgery.
• TBE can cause intestinal ileus (stopping of the gut motility and subsequent death of the animal) several weeks after injection. This is more common with TBE stored in the presence of light or heat, stored at higher than recommended doses, or given at higher than recommended concentrations.
• The effects of TBE are also somewhat unpredictable in mice younger than 16 days, or in animals with altered carbohydrate metabolism, such as various mouse strains used for diabetes or obesity models.
Policy:
Investigators may use non-pharmaceutical grade TBE if approved by the IACUC in an animal protocol. TBE must be stored and disposed of as described below.
Instructions:
Storage:
Refrigerate the aliquots and protect them from light. The material degrades rapidly in the presence of heat or light. The stock solution must be dated and stored in an amber bottle or wrapped in foil at 4°C. Even refrigerated and wrapped in foil, the material is stable for only two months. If the material degrades it becomes toxic.
Disposal:
TBE must be disposed of as normal organic waste after four months. For proper disposal of TBE, go to the EH&S website at:
http://www8.utsouthwestern.edu/utsw/cda/dept145569/files/179494.html
Contact Information:
For any additional questions concerning this policy, please contact the IACUC Manager at 5-6420.
Recommended Preparation of TBE:
It is recommended that TBE be prepared as described below.
Ingredients:
• 2.5 grams 2,2,2 Tribromoethanol
• 5 ml 2-methyl-2-butanol (amylene hydrate, tertiary amyl alcohol)
• 200 ml distilled water – neutral pH (sterile)
Preparation:
• Dissolve 2.5 grams Tribromoethanol in 5 ml amylene hydrate. This requires heating to 40°C and stirring vigorously. Be careful not to exceed 40°C.
• Add distilled water, stirring continuously, up to a final volume of 200 ml.
• Filter sterilize through a Millipore filter (0.5 micron)
• As prepared above, the solution contains 12.5 mg Tribromoethanol per ml. Do not attempt to make a more concentrated solution. The material is irritating at higher solutions.
Dosage:
• Mix solution by stirring or swirling prior to administration. The solution is given by IP injection at a dose of 250 mg/kg/BW. This amounts to 0.5 ml of the above solution to a 25 gram mouse. Induction requires only 1-2 minutes and the righting reflex returns in approximately 40 to 90 minutes.
Precautions:
• Do not administer non-sterile solutions, outdated solutions, more concentrated solutions, or higher doses than recommended above. Store the solution under refrigeration and in the dark. Containers must be wrapped in foil or stored in amber bottles.
