In July 2013, the US Food and Drug Administration approved levomilnacipran extended release (ER; Fetzima), a serotonin-norepinephrine reuptake inhibitor, for the treatment of adults with major depressive disorder. Levomilnacipran is an active enantiomer of the racemic drug milnacipran that is currently approved in the United States for the treatment of fibromyalgia. This article provides an overview of the mechanism of action, pharmacokinetic properties, clinical efficacy, safety, and tolerability of levomilnacipran ER. Relevant information was identified through a search of databases using the key word levomilnacipran. Additional information was obtained from fda.gov, by a review of the reference lists of identified articles, and from posters and abstracts from scientific meetings. Levomilnacipran ER, dosed once daily, is generally well tolerated and has demonstrated favorable effects compared to placebo in clinical trials of patients with major depressive disorder. The increased potency for norepinephrine reuptake inhibition is a characteristic that may represent a novel contribution for levomilnacipran. Additional studies comparing levomilnacipran ER to other commonly prescribed antidepressants are needed to further evaluate its place in therapy.