Comparative pharmacology of the optical isomers of ketamine in mice

Eur J Pharmacol. 1978 May 1;49(1):15-23. doi: 10.1016/0014-2999(78)90217-0.


Relative pharmacological potencies of the optical isomers of ketamine have been estimated in ICR mice. The (+)-isomer was 3X more potent than (-)-ketamine as an analgesic using the phenylquinone writhing test, only 1.5X more potent in terms of hypnotic activity and 1.8X more potent in causing locomotor stimulation. At equianalgesic doses (+)-ketamine caused less stimulation of locomotor activity than the (-)-isomer. These potency differences did not appear to be due to differences in biodisposition although stereoselective metabolism was demonstrated in vivo. Analgesia induced by ketamine was reversed by 10 mg/kg of naloxone.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Analgesics
  • Animals
  • Biotransformation
  • Brain / metabolism
  • Hypnotics and Sedatives
  • Ketamine / antagonists & inhibitors
  • Ketamine / metabolism
  • Ketamine / pharmacology*
  • Male
  • Mice
  • Mice, Inbred ICR
  • Motor Activity / drug effects
  • Naloxone / pharmacology
  • Stereoisomerism
  • Time Factors


  • Analgesics
  • Hypnotics and Sedatives
  • Naloxone
  • Ketamine