The following list includes only the commonly used anesthetic agents in cats. A list of other anesthetics suitable for specific procedures and additional information about the effects, mode of action, metabolism, and side effects of these agents are available in the CMU office, extension 6555. 

For both injectable and inhalant procedures, cats should be medicated with an anticholinergic such as atropine (0.02-0.04 mg/kg intramuscularly or subcutaneously) or glycopyrrolate (0.02 mg/kg intramuscularly or subcutaneously) to reduce salivation and maintain heart rate.

INJECTABLE AGENTS:

Ketamine - 10-11 mg/kg by intramuscular injection for restraint; 22-33 mg/kg for diagnostic or MINOR surgical procedures.  COMMENTS: Poor muscle relaxation and analgesia; when used alone it is not suitable for anything more than minor surgical procedures.

Ketamine + xylazine - 2.2 mg/kg of xylazine followed in ten minutes by 11-17.6 mg/kg of ketamine, both by intramuscular injection.  COMMENTS:  Xylazine will induce emesis in cats; adequate muscle relaxation and analgesia for short duration mild to moderate surgical procedures, can have prolonged recovery requiring significant supportive care, inhalant agents are preferred; commonly used to anesthetize cats for training in neonatal intubation.

Pentobarbital - 20-30 mg/kg by intravenous injection, initially give 1/2 the calculated dose as a bolus and an additional amount as needed.  COMMENTS: Best suited for nonsurvival procedures because of respiratory depression, poor analgesia, and prolonged often violent recovery.

Thiopental - 8-12 mg/kg by intravenous injection.  COMMENTS: Suitable for only very brief procedures such as intubation prior to inhalation anesthesia; like pentobarbital it has poor analgesia and shows respiratory depression.

Local anesthesia - see Analgesics.

INHALANT AGENTS:

Note: 1.)  Although inhalant anesthetics can be delivered in cats with a face mask for induction (provided the animal is adequately tranquilized), they must be administered via an endotracheal tube for maintenance. For intubation, cats can be preanesthetized with thiopental (see dose above) or inhalant agents administered via an enclosed chamber or a face mask.  Please contact the CMU for instruction.  2.)  Inhalation anesthesia is augmented by the use of nitrous oxide delivered a proportion of 30-70% of the inspired gases.  It will reduce the amount of inhalant agent required.

Halothane - 3-5% of inspired gas used for induction, 1.0-2.0% of inspired gas for maintenance, delivered through an endotracheal tube and a nonrebreathing apparatus with vaporizer.  COMMENTS: Requires a vaporizer, waste gases should be scavenged for personal safety reasons, rapid induction and recovery.

Isoflurane - 3-5% of inspired gas used for induction, 1-4% of inspired gas for maintenance, delivered through an endotracheal tube and a nonrebreathing apparatus with vaporizer.  COMMENTS: Requires a vaporizer, waste gases should be scavenged for personal safety reasons, rapid induction and recovery; preferred for survival procedures.