Dextromethorphan: a review of N-methyl-d-aspartate receptor antagonist in the management of pain.

Dextromethorphan (DM) is a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, which is widely used as an antitussive agent. DM also prevents neuronal damage and modulates pain sensation via noncompetitive antagonism of excitatory amino acids (EAAs). DM has been found to be useful in the treatment of pain in cancer patients and in the treatment of methotrexate-induced neurotoxicity. Clinical studies with DM in cancer patients are reviewed in this article.