Mouse Formulary The maximum recommended volume of a drug given depends on the route of administration (Formulary for Laboratory Animals, 3 rd ed.): Intraperitoneal (IP) doses should not exceed 80 ml/kg Intravenous (IP) bolus dose should not exceed 5 ml/kg Drugs administered by mouth (PO) should not exceed 50 ml/kg Subcutaneous (SC) doses should not exceed 40 ml/kg Dilution of injected drugs allows more precise dosing, but may shorten the shelf life of the compound. Aseptic technique must be observed as mixtures (cocktails) are prepared; this includes using sterile vials, syringes and needles, wiping the cover of each vial or bottle with 70% ethanol or isopropanol, diluting with Sterile Water for Injection or sterile PBS (phosphate buffered saline) and not reusing needles used for dilution or administration. As with undiluted drugs, only new, sterile needles must be used for withdrawing aliquots from the cocktail and for administering injections. Diluted drugs must be labeled and dated, then discarded after 6 months, or at the expiration date of any of the components, whichever comes first. Inhalation anesthetics Best administered using a precision vaporizer but may also be administered via nose cone containing small amount of anesthetic. Without a vaporizer the dose of isoflurane is very high, and cannot be titrated. Diluting the isoflurane in mineral oil is recommended to lessen the dose of isoflurane the animal will receive when a vaporizer is not used. For further information, please refer to the Guidelines for the use of Isoflurane anesthesia without a vaporizer for rodents. Survival surgery requires concurrent pre- emptive analgesia. Isoflurane or Sevoflurane Carbon dioxide 1-3% inhalant to effect (up to 5% for induction). Inhalant to effect (cannot determine Whenever general anesthesia is required Once, at time of euthanasia Induction is commonly performed in an induction box/chamber. Survival surgery requires concurrent pre- emptive analgesia. May be used for fast terminal procedure such as cardiac blood collection
percentage) followed by euthanasia. Injectable anesthetics- Ketamine combinations These dose combinations vary depending upon the type of procedure and the age/strain of the animal. A higher ketamine dose with lower xylazine dose is often used for very young/very old or critical patients. See cocktail recipe at the end of table. Ketamine- Xylazine Ketamine- Xylazine- Acepromazine Ketamine- Dexmedetomidine (K) 90-120 (X) 5-10 mg/kg (K) 50 100 (X) 2.5-10 (A) 2-3 mg/kg (K) 50-75 mg/kg + (D) 500 ug/kg Mouse cocktail example: First injection will last 20-30 minutes with supplemental boosters of First injection will last 30-40 minutes with supplemental boosters of Expected anesthesia of first injection is 20-30 minutes. Supplemental boosters of Ketamine/Xylazine/Acepromazine, IP administration: Ketamine 65 mg/kg Xylazine 13 mg/kg Acepromazine 2.0 mg/kg To prepare cocktail: Ketamine (100 mg/ml) 1.0 ml Xylazine (20 mg/ml) 1.0 ml Provides surgical level anesthesia. If re- dosing, Provides surgical level anesthesia. Acepromazine extends the anesthesia time for long surgical procedures. If re- dosing, May not produce surgical- plane anesthesia for major procedures. If re- dosing,
Acepromazine (10 mg/ml) Sterile water or saline 0.3 ml 7.7 ml Cocktail total volume: 10.0 ml Dose anesthetic cocktail based upon individual mouse body weight: Mouse body weight Volume cocktail 20 g 0.13 ml 25 g 0.16 ml 30 g 0.20 ml 35 g 0.23 ml This cocktail is useful for longer more invasive surgical procedures in mice. It provides anesthesia for 45-60 minutes. If the acepromazine is eliminated, the anesthesia will be shorter and the recovery faster. Reversal of alpha- 2 agents- Atipamezole is more specific for dexmedetomidine than for xylazine. Atipamezole is a more complete alpha- 2 reversal agent than yohimbine with fewer side effects. Side effects of yohimbine include CNS excitement, muscle tremors, salivation, and increased respiratory rate. Atipamezole Yohimbine 0.1 2.0 mg/kg IP, IV, SC 0.2 mg/kg IV or 1-2.1mg/kg IP Other injectable anesthetics Once. Repeat if needed Once. Repeat if needed. Sodium pentobarbital (Nembutal) 40 90 mg/kg IP Duration of anesthesia expected with first injection is 20-40 minutes. Recommended for terminal/acute procedures only, with booster doses as needed. May be appropriate for some Dose will vary depending on dexmedetomidine or xylazine dose given. For reversal of xylazine effects. Only provides partial reversal of xylazine effects. Consider supplemental analgesia (opioid or NSAID) for invasive procedures, especially when used on a survival basis. Very long acting with a long recovery period. Keep animal warm.
Tribromoethanol (Avertin) 200 240 mg/kg IP Tribromoethanol (Avertin) recipe: survival procedures such as intracranial or cranial surgery May be used for only a single survival procedure. Expect 15-20 minutes anesthesia time. (Booster as necessary during procedure). Use fresh solution (<1 week of age). See recipe below. 100% stock solution: Dissolve 10 g 2, 2, 2- tribromoethanol in 10ml amylene hydrate (tertiary amyl alcohol, 2 methyl- 2- butanol). Make sure fully dissolved, heat up to 50 o C. Solution should be clear. Store wrapped in foil (light sensitive solution, ok to use brown glass bottle), at - 20 o C. Date and label bottle. Stock solution can be kept for up to one year. 1.25% working solution 12.5 mg/ml): Mix 0.5 ml of stock solution with 39.5 ml sterile isotonic saline. Recommended to be used the same day it is prepared, but can be stored at 4 o C or frozen at - 20 O C for up to a week, in a foil wrapped container or brown bottle. Use the frozen aliquots the same day after thawed to 37 o C and shaken; discard frozen aliquots after 1 week. Date and label all bottles. Recheck ph prior to use. If ph <5, the solution becomes discolored or if precipitate is present after shaking, these are indicators that the solution has decomposed. If any of these are noted in the solution, do not use and discard. In keeping with IACUC policy, tribromoethanol must be prepared, sterilized with a 0.2- micron filter, stored and used with aseptic technique. Dosing from working solution: Mouse body weight Volume administered from working solution 200mg/kg 240mg/kg 20 g 0.3 0.4 ml 25 g 0.4 0.5 ml 30 g 0.5 0.6 ml 35 g 0.6 0.7 ml Opioid analgesia Buprenorphine 0.05 0.1 mg/kg SC Used pre- operatively for preemptive analgesia and For major procedures, requires more frequent
post- operatively every 8-12 dosing than 12- hour intervals. Consider multi- modal analgesia with an NSAID Reversal agents for opioids Naloxone 0.01-0.10 mg/kg IV or IP Once as needed to reverse respiratory depression Note that reversal will also remove the analgesic effect of the opioid Non- steroidal anti- inflammatory drugs (NSAID) analgesia- Note that prolonged use may cause renal, gastrointestinal or other problems Carprofen (Rimadyl ) 2-5 mg/kg SC Used pre- operatively for pre- emptive analgesia and post- operatively every 12-24 Depending on the procedure may be used as sole analgesic, or as multi- modal analgesia with buprenorphine. Meloxicam (Metacam ) 1-2 mg/kg SC Used pre- operatively for pre- emptive analgesia and post- operatively every 24 Depending on the procedure, it may be used as sole analgesic, or as multi- modal analgesia with buprenorphine.