Ketamine

Name: Ketamine (ketamine hydrochloride)

Trade Name(s): Ketaset, Ketalean, Rogarsetic, Vetalar

Preparation: Ketamine hydrochloride is supplied as a injectable solution at a concentration of 100 mg/ml.  The solution is slightly acid (pH 3.5‑5.5).  It is supplied in 10 ml and 50 ml bottles.

Description: Ketamine is a rapid acting anesthetic producing an anesthetic state termed "dissociative anesthesia" because it appears to selectively interrupt association of the brain before producing sensory blockade.  It also produces analgaesla.  Pharyngeal ‑ laryngeal reflexes are maintained, as is skeletal muscle tone.

Availability: Ketamine is a prescription drug.

Indications: Useful as a rapid onset, short acting general anesthetic in a wide range of species.  It is best used for short surgical procedures or for chemical restraint for minor procedures.

Dosage: A wide range of doses have been used in a wide range of species.  Consult your laboratory animal veterinarian.

Routes of administration: Ketamine can be administered parenterally by intramuscular, subcutaneous or intraperitoneal injection.

Duration of action: Following injection of recommended doses, most animals become ataxic in about five minutes; anesthesia lasts about 30 minutes.  Recovery is generally smooth if the animal is not stimulated or handled.  Complete recovery usually occurs within four to five hours.

Mechanism of action: Ketamine produces an anaesthetic state termed "dissociative anaesthesia" because it appears to selectively interrupt association of the brain before producing sensory blockade.

Clinical pharmacology: Ketamine hydrochloride is a nonbarbiturate general anaesthetic in the cyclohexylamine group, with the chemical name 2‑(o‑chlorophenyl)‑2‑methylamino cyclohexanone hydrochloride.

Physiological effects:

         Cardiovascular: There is mild cardiac stimulation, blood pressure and heart rate are usually moderately and transiently increased.

         Respiratory: There is respiratory depression; the respiratory rate is usually decreased.

Drug Interactions: Ketamine can be used in effective combinations with a variety of sedatives or tranquilisers.

Notes:  Many protective reflexes are not abolished, and so monitoring the depth of anesthesia is not similar to other general anesthetics.  The eyes remain open with the pupil dilated so lubricating eye ointments should be instilled.

References:

Compendium of Veterinary Products, 6th Ed.  1999.  Canadian Animal Health Institute.  North American Compendiums, Hensall, Ontario

Pain Management in Animals.  2000  Flecknell P and Waterman-Pearson A (eds). WB Saunders, London  184pp

Laboratory Animal Anesthesia.  1996.  Flecknell P.  Academic Press, London.  274 pp.