Ketamine enantiomers in the rapid and sustained antidepressant effects.

Recent evidence has suggested that the N-methyl-D-aspartate receptor antagonist ketamine shows significant therapeutic effects in major depression and bipolar disorder. This effect is especially important in treatment-resistant depression and depression with suicidal ideation. In this review we explain the mechanism of action, drug efficacy, and the side effects of ketamine; the antidepressive effects of ketamine; the individual effects of ketamine isomers, R(-) ketamine and S(+) ketamine; the effects of the combination of ketamine with electroconvulsive therapy; and the possible use of ketamine in treating depression.