Mechanism of action of dextromethorphan/quinidine:comparison with ketamine.

Reports of rapid-onset but short-duration antidepressant effects in patients with treatment-resistant mood disorders after intravenous administration of ketamine have prompted efforts to find an agent with ketamine's properties that can be administered orally in repeated doses in order to sustain that action. One candidate for this dextromethorphan, and here the pharmacologic mechanism of action is compared and contrasted with that of ketamine.