Abstract: The present invention is directed to pharmaceutical compositions of effective amounts of NMDA receptor antagonists and preservative for the administration to a patient in need of effective analgesia and anesthesia. The compositions of the invention advantageously do not cause any significant neurotoxicity. The preferred NMDA receptor antagonist is ketamine. The preferred preservative is benzalkonium chloride.

Abstract: The present invention is directed to pharmaceutical compositions of effective amounts of NMDA receptor antagonists and non-neurotoxic compounds having preservative activity for the administration to a patient in need of effective analgesia and anesthesia. The compositions of the invention advantageously do not cause any significant neurotoxicity. The preferred NMDA receptor antagonist is ketamine. The non-neurotoxic compound is selected from one of the following groups including organic acids, esters thereof, and salts thereof; alcohols, polyols, and phenols; alkyl parabens; cresols; benzalkonium chloride quaternary ammonium salts; chlorhexidine, imidurea, alpha tocopherol, and EDTA. Preferably, the nonneurotoxic compound is benzalkonium chloride, benzyl alcohol or phenol.

Abstract: The present invention is directed to pharmaceutical compositions of effective amounts of NMDA receptor antagonists and preservative for the administration to a patient in need of effective analgesia and anesthesia. The compositions of the invention advantageously do not cause any significant neurotoxicity. The preferred NMDA receptor antagonist is ketamine. The preferred preservative is benzalkonium chloride.