Rat Formulary

DRUG NAME DOSE (mg/kg) & ROUTE FREQUENCY NOTES
Anticholinergics – Prevents bradycardia and cardiac arrhythmias . Not commonly used in rats.
Atropine 0.02-0.05 IM or SC Once at induction
  • Recommended: Glycopyrrolate
0.01- 0.02 IM or SC Once at induction
Inhalation anesthetics – Best administered using a precision vaporizer but may also be administered via nose cone containing small amount of anesthetic. Survival surgery requires concurrent pre-emptive analgesia.
  • Recommended: Isoflurane or Sevoflurane
1-3% inhalant to effect (up to 5% for induction). Up to 8% for Sevoflurane Whenever general anesthesia is required Survival surgery requires concurrent pre-emptive analgesia.
Carbon dioxide To effect (cannot determine percentage) Once, at time of euthanasia May be used for fast terminal procedure such as cardiac blood collection followed by euthanasia
Ketamine combinations – These dose combinations vary depending upon the type of procedure and the age/strain of the animal. Higher ketamine dose with lower xylazine dose are used for less invasive procedures and for very young/very old or critical patients. In general, higher doses of xylazine with concomitant lowering of the ketamine dose are used for more invasive procedures. See cocktail recipe at the end of table.
Ketamine-Medetomidine 40 – 80 + ~0.5-1 IP (in same syringe) As needed May not produce surgical-plane anesthesia for major procedures. If redosing, use ¼ dose of cocktail.
  • Recommended: Ketamine-Xylazine

40 – 80

+ 5-10 IP (in same syringe)

As needed May not produce surgical-plane anesthesia for major procedures, though more reliable than in mice. If redosing, use1/4 dose of cocktail. May be partially reversed with Atipamezole or Yohimbine
Ketamine-Xylazine-Acepromazine

40-80

+ 5-10

+ 1 (in same syringe)

Once, to induce anesthesia. Repeat ¼ dose as needed May not produce surgical-plane anesthesia for major procedures. If redosing, use1/4 dose of cocktail. May be partially reversed with Atipamezole or Yohimbine
Ketamine-Midazolam

75-100

+ 4-5 IP (in same syringe)

As needed May not produce surgical-plane anesthesia for major procedures, but may be useful for restraint.
Rat cocktails

1) Ketamine/xylazine                                  Dosing /100 g IP

0.2 ml 0.3 ml 0.4 ml
Ketamine (100 mg/ml)    6.0 ml                     40 mg/kg       60 mg/kg       80 mg/kg
Xylazine (20 mg/ml)      3.75 ml                     5 mg/kg        7.5 mg/kg       10 mg/kg
Sterile water or saline  20.25 ml
————————————–
Cocktail                    = 30.0 ml

The lower dose provides light anesthesia for short non-painful or minimally painful procedures.
The middle dose provides anesthesia for 30-45 minutes of surgery.
The upper dose provides deep anesthesia for terminal procedures, for example perfusion.

2. Ketamine/xylazine/acepromazine Dosing/100 g IP

0.3 ml
Ketamine (100 mg/ml)         6.0 ml                  60 mg/kg
Xylazine (20 mg/ml)           3.75 ml                7.5 mg/kg
Acepromazine (10 mg/ml)    1.0 ml                1.0 mg/kg
Sterile water or saline       19.25 ml
————————————–
Cocktail                             30.0 ml

This cocktail is useful for longer more invasive surgical procedures. It provides anesthesia for 45 -60 minutes.

Reversal agents – Atipamezole is more specific for medetomidine than for xylazine (as a general rule, Atipamezole is dosed at the same volume as Medetomidine, though they are manufactured at different concentrations)
Atipamezole 0.1 – 1.0 SC, IP Once. Repeat as needed. Any time medetomidine or xylazine has been used
Yohimbine 1.0 – 2.0 SC or IP Once. Repeat as needed. For reversal of xylazine effects
Other injectable anesthetics
Sodium pentobarbital (Nembutal) 30 – 50 IP Recommended for terminal/acute procedures only, with booster doses as needed. May be appropriate for some survival procedures such as intracranial surgery 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.
Propofol 12-26 IV As needed Only useful IV, so therefore limited usefulness in rats. Respiratory depression upon induction is possible.
Opioid analgesia
  • Recommended: Buprenorphine
0.025 – 0.075 SC, IP, IV Used pre-operatively for preemptive analgesia and post-operatively every 6-12 hour For major procedures, require more frequent dosing than 12 hour intervals. Consider multi-modal analgesia with a NSAID. High doses of buprenorphine may lead to pica behavior in rats.
Butorphanol 0.05 – 2.0 SC Every 4-6 hours Useful for short, minor procedures.
Morphine 2 –5 IP, SQ Every 2 -4 hours As pre-emptive analgesia and post-procedural analgesic for very painful procedures
Reversal agents for opioids
Naloxone 0.01 -0.1 IV, IM Once as needed to reverse respiratory depression Note that reversal will also remove the analgesic effect of the opioid
Non-steroidal anti-inflammatory analgesia (NSAID) Note that prolonged use may cause renal, gastrointestinal, or other problems
  • Recommended: Carprofen
4-5 SC Used pre-operatively for preemptive analgesia and post-operatively every 12-24 hour Depending on the procedure, may be used as sole analgesic, or as multi-modal analgesia with buprenorphine.
  • Recommended: Meloxicam Metacam®
0.3 – 1.0 IM, IP, SC, PO Used pre-operatively for preemptive analgesia and post-operatively every 12-24 hour Depending on the procedure, may be used as sole analgesic, or as multi-modal analgesia with buprenorphine. Drinking water dose: 10.89ug/ml (1.0 mg/kg/day). Use injectable form of meloxicam to prepare drinking water: Meloxicam suspension does not dissolve well in water.
  • Recommended: Ketoprofen
2 – 5 SC Used pre-operatively for preemptive analgesia and post-operatively every 12-24 hour Depending on the procedure, may be used as sole analgesic, or as multi-modal analgesia with buprenorphine.

Ketorolac

Toridol®

3 – 5 PO Used pre-operatively for preemptive analgesia and post-operatively every 12-24 hour Depending on the procedure, may be used as sole analgesic, or as multi-modal analgesia with buprenorphine.
Flunixin meglubin Banamine® 1.0 – 2.0 SC, IM For supplemental postop analgesia Every 24 hours for no more than 3 days Useful for treating hyperthermia
Local anesthetic/analgesics (lidocaine and bupivacaine may be combined in one syringe for rapid onset and long duration analgesia)
Lidocaine hydrochloride Dilute to 0.5%, do not exceed 7 mg/kg total dose, SC or intra-incisional Use locally before making surgical incision Faster onset than bupivacaine but short (<1 hour) duration of action
Bupivacaine Dilute to 0.25%, do not exceed 8 mg/kg total dose, SC or intra-incisional Use locally before making surgical incision Slower onset than lidocaine but longer (~ 4-8 hour) duration of action
BU IACUC Approved October 2008